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Sample records for chain chlorinated aliphatic

  1. Complete detoxification of short chain chlorinated aliphatic compounds: Isolation of halorespiring organisms and biochemical studies of the dehalogenating enzyme systems. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Tiedje, J.M.

    1998-06-01

    'Widespread use and careless handling, storage and disposal practices, have lead to the dissemination of chlorinated short chain aliphatics into groundwater systems. These compounds are toxic and the presence of chlorinated ethenes and chlorinated propanes in the environment is of public concern. Halorespiration is a newly recognized anaerobic process by which certain bacteria use chlorinated compounds as terminal electron acceptors in their energy metabolism. In contrast to co-metabolic dechlorination, which is fortuitous, slow, and without benefit to the organisms, halorespiration, characterized by high dechlorination rates, is a specific metabolic process beneficial to the organism. The goals are to isolate and characterize organisms which use chlorinated ethenes (including tetrachloroethene [PCE], trichloroethene [TCE], cis-dichloroethene [cis-DCE], and vinyl chloride [VC], or 1,2-dichloropropane [1,2-D]) as electron acceptors in their energy metabolism. Better understanding of the physiology and phylogeny of the halorespiring organisms as well as the biochemistry of the dehalogenating enzyme systems, will greatly enhance the authors knowledge of how these organisms can successfully be employed in the bioremediation of contaminated sites. This report summarizes the results of 1.5 years of a 2-year project. Anaerobic microcosms were established using a variety of geographically distinct sediments. In several microcosms complete dechlorination of PCE to ethene (ETH), and 1,2-D to propene was observed. Upon subsequent transfers to anaerobic medium, four sediment-free, methanogenic enrichment cultures were obtained that dechlorinated PCE to ETH, and two cultures that dechlorinated 1,2-D to propene. 2-Bromoethanesulfonate (BES), a well known inhibitor of methanogens, did not inhibit the dechlorination of 1,2-D to propene or the dechlorination of PCE to cis-DCE. However, the complete dechlorination of PCE to VC and ETH was severely inhibited. They could also

  2. Estimates of Gibbs free energies of formation of chlorinated aliphatic compounds

    NARCIS (Netherlands)

    Dolfing, Jan; Janssen, Dick B.

    1994-01-01

    The Gibbs free energy of formation of chlorinated aliphatic compounds was estimated with Mavrovouniotis' group contribution method. The group contribution of chlorine was estimated from the scarce data available on chlorinated aliphatics in the literature, and found to vary somewhat according to the

  3. Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids.

    Science.gov (United States)

    Wang, Zhentao; Zhu, Lin; Yin, Feng; Su, Zhongquan; Li, Zhaodong; Li, Chaozhong

    2012-03-07

    Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)(2)OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.

  4. Complete detoxification of short chain chlorinated aliphatics: Isolation of halorespiring organisms and biochemical studies of the dehalogenating enzyme systems. 1997 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, F.E.; Tiedje, J.M.

    1997-01-01

    'The objectives of the research within this grant are: (1) Isolation and characterization of chlororespiring organisms responsible for the complete dehalogenation of chlorinated ethenes and propanes. (2) Development of conditions that yield high cell densities and induce dechlorinating activity. (3) Development of assay systems to detect the dechlorinating activity in cell-free extracts. (4) Purification and characterization of the dehalogenating enzymes. Anaerobic microcosms were obtained from a variety of geographically different sediment samples. In several microcosms complete dechlorination of tetrachloroethene (PCE) to ethene (ETH), and 1,2-dichloropropane ( 1,2-D) and/or 1,2,3-trichloropropane to propene was observed. Upon subsequent transfers to anaerobic medium, sediment-free, methanogenic enrichment cultures were obtained that dechlorinated PCE to ETH, and 1,2-D to propene, respectively. 2-Bromoethanesulfonate (BES), a well known inhibitor of methanogens, did not inhibit the dechlorination of 1,2-D to propene and the dechlorination of PCE to cis-dichloroethene (cis-DCE). However,-the complete dechlorination of PCE to vinyl chloride (VC) and ETH was severely inhibited. The authors could show that BES inhibited the dechlorination of chloroethenes in cultures not containing methanogens. Previous to this study, BES was believed to be aspecific inhibitor of methanogens and the inhibitory effect of BES on declorination was explained by the involvement of methanogens in the dechlorination process. The non-methanogenic cultures obtained after the BES treatment were subsequently transferred to medium riot containing BES and complete dechlorination of PCE to ETH was observed as was in the original microcosms. Subcultures were further enriched with PCE, cis-DCE, VC, or 1,2-D as the only available electron acceptor and acetate, or acetate plus hydrogen as the only available electron donor(s). To date these cultures have undergone up to 45 transfers. Interestingly

  5. Biodegradation and metabolic pathway of β-chlorinated aliphatic acid in Bacillus sp. CGMCC no. 4196.

    Science.gov (United States)

    Lin, Chunjiao; Yang, Lirong; Xu, Gang; Wu, Jianping

    2011-04-01

    In this study, a bacterial Bacillus sp. CGMCC no. 4196 was isolated from mud. This strain exhibited the ability to degrade high concentration of 3-chloropropionate (3-CPA, 120 mM) or 3-chlorobutyrate (30 mM), but not chloroacetate or 2-chloropropionate (2-CPA). The growing cells, resting cells, and cell-free extracts from this bacterium had the capability of 3-CPA degradation. The results indicated that the optimum biocatalyst for 3-CPA biodegradation was the resting cells. The 3-CPA biodegradation pathway was further studied through the metabolites and critical enzymes analysis by HPLC, LC-MS, and colorimetric method. The results demonstrated that the metabolites of 3-CPA were 3-hydroxypropionic acid (3-HP) and malonic acid semialdehyde, and the critical enzymes were 3-CPA dehalogenase and 3-HP dehydroxygenase. Thus, the mechanism of the dehalogenase-catalyzed reaction was inferred as hydrolytic dehalogenation which was coenzyme A-independent and oxygen-independent. Finally, the pathway of β-chlorinated aliphatic acid biodegradation could be concluded as follows: the β-chlorinated acid is first hydrolytically dehalogenated to the β-hydroxyl aliphatic acid, and the hydroxyl aliphatic acid is oxidized to β-carbonyl aliphatic acid by β-hydroxy aliphatic acid dehydroxygenase. It is the first report that 3-HP was produced from 3-CPA by β-chlorinated aliphatic acid dehalogenase.

  6. The use of DNA technologies in determining the biotreatability of chlorinated aliphatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, A. [HydroQual, Calgary, AB (Canada)

    2008-07-01

    HydroQual Laboratories is a wholly-owned subsidiary of Golder Associates and uses biological testing for measuring the effect of toxins and their impact on various links in the food chain in order to evaluate and improve environmental health. It has expertise in various fields of the natural sciences and is ISO certified. This presentation discussed the use of DNA technologies in determining the biotreatability of chlorinated aliphatic hydrocarbons. The paper presented biotreatability studies run by the company which included bench scale testing on various types of contaminants. The testing involved multiple treatments, determination of dosage, and additional amendments. The strategy may vary based on bench test results and legislation. Trichloroethylene/perchloroethylene remediation strategies were also presented for chemical oxidation; aerobic bioremediation; abiotic remediation; and anaerobic biostimulation and augmentation. Biostimulation was defined as the addition of nutrients to influence the redox potential. The presentation also reviewed anaerobic dehalorespiration; detection methods; DNA isolation; polymerase chain reaction (PCR); and biotreatability case studies. The presentation concluded with some future directions and other uses of PCR. tabs., figs.

  7. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    Science.gov (United States)

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided.

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

    Science.gov (United States)

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

    2016-09-01

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

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

    Science.gov (United States)

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

    2008-05-01

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

  10. Calamistrin E, the First Annonaceous Acetogenin with Double Bond in Aliphatic Chain from Genus Uvaria

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Calamistrin E, the first Annonaceous acetogenin with C=C bond in the aliphatic chain from the genus Uvaria was isolated from U. calamistrata. Its structure including relative and absolute configurations was determined by chemical derivation and spectral analysis.

  11. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots

    Science.gov (United States)

    Powell, C. L.; Goltz, M. N.; Agrawal, A.

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~ 1.9 mg L- 1, and initial aqueous [CAH] ~ 150 μg L- 1; cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12 ± 0.01 and 0.59 ± 0.07 d- 1, respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  12. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots.

    Science.gov (United States)

    Powell, C L; Goltz, M N; Agrawal, A

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~1.9mgL(-1), and initial aqueous [CAH] ~150μgL(-1); cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12±0.01 and 0.59±0.07d(-1), respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  13. Effects of short-chain chlorinated paraffins on soil organisms.

    Science.gov (United States)

    Bezchlebová, Jitka; Cernohlávková, Jitka; Kobeticová, Klára; Lána, Jan; Sochová, Ivana; Hofman, Jakub

    2007-06-01

    Despite the fact that chlorinated paraffins have been produced in relatively large amounts, and high concentrations have been found in sewage sludge applied to soils, there is little information on their concentrations in soils and the effect on soil organisms. The aim of this study was to investigate the toxicity of chlorinated paraffins in soils. The effects of short-chain chlorinated paraffins (64% chlorine content) on invertebrates (Eisenia fetida, Folsomia candida, Enchytraeus albidus, Enchytraeus crypticus, Caenorhabditis elegans) and substrate-induced respiration of indigenous microorganisms were studied. Differences were found in the sensitivity of the tested organisms to short-chain chlorinated paraffins. F. candida was identified as the most sensitive organism with LC(50) and EC(50) values of 5733 and 1230 mg/kg, respectively. Toxicity results were compared with available studies and the predicted no effect concentration (PNEC) of 5.28 mg/kg was estimated for the soil environment, based on our data.

  14. Effects of alkyl side chains on properties of aliphatic amino acids probed using quantum chemical calculations.

    Science.gov (United States)

    Ganesan, Aravindhan; Wang, Feng; Brunger, Michael; Prince, Kevin

    2011-09-01

    Effects of alkyl side chains (R-) on the electronic structural properties of aliphatic amino acids are investigated using quantum mechanical approaches. The carbon (C 1s) binding energy spectra of the aliphatic amino acids are derived from the C 1s spectrum of glycine (the parent spectrum) by the addition of spectral peaks, depending on the alkyl side chains, appearing in the lower energy region IP aliphatic amino acids owing to perturbations depending on the size and structure of the alkyl chains. The pattern of the N 1s and O 1s spectra in glycine is retained in the spectra of the other amino acids with small shifts to lower energy, again depending on the alkyl side chain. The Hirshfeld charge analyses confirm the observations. The alkyl effects on the valence binding energy spectra of the amino acids are concentrated in the middle valence energy region of 12-16 eV, and hence this energy region of 12-16 eV is considered as the `fingerprint' of the alkyl side chains. Selected valence orbitals, either inside or outside of the alkyl fingerprint region, are presented using both density distributions and orbital momentum distributions, in order to understand the chemical bonding of the amino acids. It is also observed that the HOMO-LUMO energy gaps of the aliphatic amino acids are reduced with the growth of the alkyl side chain.

  15. Modification of eucalyptus pulp fiber using silane coupling agents with aliphatic side chains of different length

    Science.gov (United States)

    The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) we...

  16. Physical property determinations of short chain chlorinated paraffins

    Energy Technology Data Exchange (ETDEWEB)

    Drouillard, K.G.D. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Soil Science; Hiebert, T.; Friesen, K.J. [Univ. of Winnipeg, Manitoba (Canada). Dept. of Chemistry; Muir, D.C.G. [Freshwater Inst., Winnipeg, Manitoba (Canada)

    1995-12-31

    Chlorinated paraffins (CP) are chlorinated derivatives of n-alkanes commonly utilized in commercial formulations of flame retardants, plasticizers and high pressure lubricants. Recent reviews on CPs have expressed concern regarding the potential toxicity and carcinogenic properties of these compounds. Of the various classes of CPs, short chain compounds (carbon chain lengths 10 to 13) appear to pose the greatest risk. There is little data available concerning key physical properties of CPs required to assess their environmental behavior and mobility. In this study, water solubilities, dissolved organic matter water partition coefficients (K{sub DOM}) and Henry`s Law constants were determined for short chain chlorinated paraffins by generator column, apparent solubility enhancement and gas-purging techniques. Water solubilities were determined for synthesized, isolated products of polychlorinated decanes, undecanes and dodecanes. Solubilities at 25 C were on the order of 2 to 140 {micro}g/L for tetra- to hexachlorodecane products. The Henry`s Law constants for tetra- and pentachlorodecane were determined to be 6.6 {+-} 0.6 and 3.5 {+-} 0.6 Pa{center_dot}m{sup 3}{center_dot}mol{sup {minus}1} respectively. Relationships between carbon chain length and degree of chlorination on the determined physical properties will be discussed.

  17. In Situ and Laboratory Studies on the Fate of Specific Organic Compounds in an Anerobic Landfill Leachate Plume, 2. Fate of Aromatic and Chlorinated Aliphatic Compounds

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Bjarnadóttir, Helga; Winter, Pia L.;

    1995-01-01

    and laboratory batch microcosm experiments performed focusing on redox conditions, microbiology and the fate of 7 phenolic compounds. In this paper we present the results on the fate of 8 aromatic compounds and 4 chlorinated aliphatic compounds. Nitrobenzene was transformed at all distances from the landfill...

  18. Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

    OpenAIRE

    RAMASAMY ANBARASAN; SEUNG SOON IM; WANDUC LEE

    2008-01-01

    The inter-layer anion of layered double hydroxides (LDH) with a hydrotalcite (HT)-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH ...

  19. Phenolic and short-chained aliphatic organic acid constituents of wild oat (Avena fatua L.) seeds.

    Science.gov (United States)

    Gallagher, R S; Ananth, R; Granger, K; Bradley, B; Anderson, J V; Fuerst, E P

    2010-01-13

    The objective of this research was to identify and quantify the phenolic and short-chained aliphatic organic acids present in the seeds of three wild-type populations of wild oat and compare these results to the chemical composition of seeds from two commonly utilized wild oat isolines (M73 and SH430). Phenolic acids have been shown to serve as germination inhibitors, as well as protection for seeds from biotic and abiotic stress factors in other species, whereas aliphatic organic acids have been linked to germination traits and protection against pathogens. Wild oat populations were grown under a "common garden" environment to remove maternal variation, and the resulting seeds were extracted to remove the readily soluble and chemically bound phenolic and aliphatic organic acid components. Compounds were identified and quantified using gas chromatography-mass spectrometry. Ferulic and p-coumaric acid comprised 99% of the total phenolic acids present in the seeds, of which 91% were contained in the hulls and 98% were in the chemically bound forms. Smaller quantities of OH benzoic and vanillic acid were also detected. Soluble organic acids concentrations were higher in the M73 isoline compared to SH430, suggesting that these chemical constituents could be related to seed dormancy. Malic, succinic, fumaric and azelaic acid were the dominant aliphatic organic acids detected in all seed and chemical fractions.

  20. Fenton process for degradation of selected chlorinated aliphatic hydrocarbons exemplified by trichloroethylene, 1,1-dichloroethylene and chloroform

    Institute of Scientific and Technical Information of China (English)

    Zhimin QIANG; Weiwei BEN; ChinPao HUANG

    2008-01-01

    The degradation of selected chlorinated ali-phatic hydrocarbons (CAHs) exemplified by trichloroethy-lene (TCE), 1,1-dichloroethylene (DCE), and chloroform (CF) was investigated with Fenton oxidation process. The results indicate that the degradation rate was primarily affected by the chemical structures of organic contami-nants. Hydroxyl radicals (·OH) preferred to attack the organic contaminants with an electron-rich structure such as chlorinated alkenes (i.e., TCE and DCE). The dosing mode of Fenton's reagent, particularly of Fe2+, significantly affected the degradation efficiency of studied organic compound. A new "time-squared" kinetic model, C = Coexp(-kobst2), was developed to express the degrada-tion kinetics of selected CAHs. This model was applicable to TCE and DCE, but inapplicable to CF due to their varied reaction rate constants towards ·OH. Chloride release was monitored to examine the degree of dechlorina- tion during the oxidation of selected CAHs. TCE was more easily dechlorinated than DCE and CF. Dichloroacetic acid (DCAA) was identified as the major reaction intermediate in the oxidation of TCE, which could be completely removed as the reaction proceeded. No reaction intermedi- ates or byproducts were identified in the oxidation of DCE and CF. Based on the identified intermediate, the reaction mechanism of TCE with Fenton's reagent was proposed.

  1. Analysis of short-chain chlorinated paraffins: a discussion paper.

    Science.gov (United States)

    Pellizzato, Francesca; Ricci, Marina; Held, Andrea; Emons, Hendrik

    2007-09-01

    Short-chain chlorinated paraffins are a class of organic compounds widely used in many industrial applications, extensively diffused into the environment, persistent, bioaccumulative, and toxic towards aquatic organisms. However, their study and monitoring in the environment are still limited. Because of the enormous number of positional isomers that characterise their mixtures, the analysis of this class of pollutants is very difficult to perform. Beside this, the lack of certified reference materials poses a problem for the assessment of the quality assurance/quality control of any analytical procedure. At present, the scientific community does not agree on any analytical reference method, although the monitoring of short-chain chlorinated paraffins has already started in order to comply with the Water Framework Directive of the European Union on water quality. In this paper the regulatory framework, in which chlorinated paraffins are included, and the status concerning their determination are summarized. The main analytical difficulties still existing are discussed, and the definition of a method-defined parameter as well as the development of a standardised method are suggested as a way to obtain comparable monitoring data.

  2. Formation and detoxification of reactive intermediates in the metabolism of chlorinated ethenes

    NARCIS (Netherlands)

    Vlieg, JETV; Janssen, DB; Hylckama Vlieg, Johan E.T. van

    2001-01-01

    Short-chain halogenated aliphatics, such as chlorinated ethenes, constitute a large group of priority pollutants. This paper gives an overview on the chemical and physical properties of chlorinated aliphatics that are critical in determining their toxicological characteristics and recalcitrance to b

  3. Trapping by amylose of the aliphatic chain grafted onto chlorogenic acid: importance of the graft position.

    Science.gov (United States)

    Le-Bail, P; Lorentz, C; Pencreac'h, G; Soultani-Vigneron, S; Pontoire, B; López Giraldo, L J; Villeneuve, P; Hendrickx, J; Tran, V

    2015-03-06

    5-Caffeoylquinic acid (chlorogenic acid), is classified in acid-phenols family and as polyphenolic compounds it possesses antioxidant activity. The oxydative modification of chlorogenic acid in foods may lead to alteration of their qualities; to counteract these degradation effects, molecular encapsulation was used to protect chlorogenic acid. Amylose can interact strongly with a number of small molecules, including lipids. In order to enable chlorogenic acid complexation by amylose, a C16 aliphatic chain was previously grafted onto the cycle of quinic acid. This work showed that for the two lipophilic derivatives of chlorogenic acid: hexadecyl chlorogenate obtained by alkylation and 3-O-palmitoyl chlorogenic acid obtained by acylation; only the 3-O-palmitoyl chlorogenic acid complexed amylose. The chlorogenic acid derivatives were studied by X-ray diffraction, differential scanning calorimetry and NMR to elucidate the interaction. By comparing the results with previous work on the complexation of amylose by 4-O-palmitoyl chlorogenic acid, the importance of the aliphatic chain position on the cycle of the quinic acid is clearly highlighted. A study in molecular modeling helped to understand the difference in behavior relative to amylose of these three derivatives of chlorogenic acid.

  4. Effect of Functional Group and Carbon Chain Length on the Odor Detection Threshold of Aliphatic Compounds

    Directory of Open Access Journals (Sweden)

    Manuel Zarzo

    2012-03-01

    Full Text Available Odor detection thresholds (ODTs are used for assessing outdoor and indoor air quality. They are obtained experimentally by olfactometry and psychophysical methods, and large compilations are available in the literature. A non-linear regression equation was fitted to describe the ODT variability of 114 aliphatic compounds based on the alkyl chain length for different homologous series (carboxylic acids, aldehydes, 2-ketones, esters, 1-alcohols, amines, thiols, thioethers and hydrocarbons. The resulting equation reveals an effect of the functional group, molecular size and also an interaction between both factors. Although the mechanistic interpretation of results is uncertain, the relatively high goodness-of-fit (R2 = 0.90 suggests that ODT values of aliphatic compounds can be predicted rather accurately, which is not the case for rigid molecules. This equation may serve as a basis for the development of more complex ODT models taking into account diverse structural features of odorants. The variability of power-law exponents was also investigated for the homologous series.

  5. Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

    Directory of Open Access Journals (Sweden)

    RAMASAMY ANBARASAN

    2008-03-01

    Full Text Available The inter-layer anion of layered double hydroxides (LDH with a hydrotalcite (HT-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH showed the highest increase of the basal spacing, which was confirmed by XRD analysis. FTIR results supported the interaction of the surfactants with the LDH. In addition, an increase in the thermal stability of the dodecanedioic acid intercalated HT was evidenced by the TGA method.

  6. Synthesis, characterization and antimicrobial studies of new bispyrazolines linked via 3-aryl ring with aliphatic chains

    Science.gov (United States)

    Yusuf, Mohamad; Jain, Payal

    2012-10-01

    The bispyrazolines 4a(a'-f') and 4b(a'-f') built around the aliphatic chains of varying lengths have been prepared by refluxing bischalcones 3a(a'-f') and 3b(a'-f') with phenyl hydrazine in alcoholic medium. The reactions of chalcones 2a and 2b with suitable 1,ω-dibromoalkanes in the presence of anhydrous K2CO3/dry acetone and Bu4N+I- (PTC) provided 3a(a'-f') and 3b(a'-f'), respectively. The antibacterial and antifungal activities of the synthesized compounds were evaluated against five bacterial and four fungal strains. The compounds 3ba', 3bc', 3bd', 3be', 3af', 4aa' and 4ba' showed better MIC (μg/mL) against the tested microorganisms.

  7. Liquid-phase synthesis of bridged peptides using olefin metathesis of a protected peptide with a long aliphatic chain anchor.

    Science.gov (United States)

    Aihara, Keisuke; Komiya, Chiaki; Shigenaga, Akira; Inokuma, Tsubasa; Takahashi, Daisuke; Otaka, Akira

    2015-02-01

    Bridged peptides including stapled peptides are attractive tools for regulating protein-protein interactions (PPIs). An effective synthetic methodology in a heterogeneous system for the preparation of these peptides using olefin metathesis and hydrogenation of protected peptides with a long aliphatic chain anchor is reported.

  8. "Green" functionalization of pristine multi-walled carbon nanotubes with long-chain aliphatic amines.

    Science.gov (United States)

    Basiuk, Elena V; Ochoa-Olmos, Omar; Contreras-Torres, Flavio F; Meza-Laguna, Víctor; Alvarez-Zauco, Edgar; Puente-Lee, Iván; Basiuk, Vladimir A

    2011-06-01

    Short pristine multi-walled carbon nanotubes (MWNTs) were functionalized with a series of long-chain (including polymeric) aliphatic amines, namely octadecylamine (ODA), 1,8-diaminooctane (DO), polyethylene glycol diamine (PEGDA) and polyethylenimine (PEI), via two "green" approaches: (1) gas-phase functionalization (for volatile ODA and DO) and (2) direct heating in the melt (for polymeric PEGDA and PEI). Both of them consist in one-step reaction between MWNTs and amine without the use of organic solvents. The nanostructures obtained were characterized by using infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. It was observed that both solvent-free methods were efficient in the nanotube functionalization, and the nanostructures of variable solubility and morphology were obtained depending on the amines attached. ODA, PEGDA and PEI-functionalized MWNTs were found to be soluble in propanol, meanwhile the MWNTs-PEGDA and MWNTs-PEI were soluble in water as well. The attachment of 1,8-diaminooctane onto MWNTs resulted in cross-linked stable nanostructure.

  9. Determination of Short-Chain Chlorinated Paraffins by Carbon Skeleton Gas Chromatography

    OpenAIRE

    PELLIZZATO FRANCESCA; RICCI MARINA; HELD ANDREA; EMONS HENDRIK

    2008-01-01

    Short-Chain Chlorinated Paraffins (SCCPs) are highly complex technical mixtures of polychlorinated n-alkanes with a chlorination degree between 50 and 70 % by mass, and a linear carbon chain length from C10 to C13, constituted by thousands of homologues, diastereomers and enantiomers. They have been used in many different applications, such as extreme pressure additives in lubricants and cutting fluids, plasticizers in PVC, and flame retardants in paints, adhesives and sealants. SCCPs are tox...

  10. Industrial metabolism of chlorine: a case study of a chlor-alkali industrial chain.

    Science.gov (United States)

    Han, Feng; Li, Wenfeng; Yu, Fei; Cui, Zhaojie

    2014-05-01

    Substance flow analysis (SFA) is applied to a case study of chlorine metabolism in a chlor-alkali industrial chain. A chain-level SFA model is constructed, and eight indices are proposed to analyze and evaluate the metabolic status of elemental chlorine. The primary objectives of this study are to identify low-efficiency links in production processes and to find ways to improve the operational performance of the industrial chain. Five-year in-depth data collection and analysis revealed that system production efficiency and source efficiency continued increasing since 2008, i.e., when the chain was first formed, at average annual growth rates of 21.01 % and 1.01 %, respectively. In 2011, 64.15 % of the total chlorine input was transformed into final products. That is, as high as 98.50 % of the chlorine inputs were utilized when other by-products were counted. Chlorine loss occurred mostly in the form of chloride ions in wastewater, and the system loss rate was 0.54 %. The metabolic efficiency of chlorine in this case was high, and the chain system had minimal impact on the environment. However, from the perspectives of processing depth and economic output, the case study of a chlor-alkali industrial chain still requires expansion.

  11. Evaluation of solid polymeric organic materials for use in bioreactive sediment capping to stimulate the degradation of chlorinated aliphatic hydrocarbons

    NARCIS (Netherlands)

    Atashgahi, S.; Maphosa, F.; Vrieze, de J.; Haest, P.J.; Boon, N.; Smidt, H.; Springael, D.; Dejonghe, W.

    2014-01-01

    In situ bioreactive capping is a promising technology for mitigation of surface water contamination by discharging polluted groundwater. Organohalide respiration (OHR) of chlorinated ethenes in bioreactive caps can be stimulated through incorporation of solid polymeric organic materials (SPOMs) that

  12. A novel high-performance thin layer chromatography method for quantification of long chain aliphatic hydrocarbons from Cissus quadrangularis

    Directory of Open Access Journals (Sweden)

    Vandana Jain

    2016-08-01

    Full Text Available Context: A high-performance thin layer chromatography (HPTLC is an analytical technique, which can be used for the determination of constituents or marker components in various parts of the plants. Earlier studies have estimated phytoconstituents from the stem and other aerial plant parts of Cissus quadrangularis Linn. Estimation of hydrocarbons can also be successfully done using HPTLC technique using suitable derivatization. Aims: To develop and validate a simple and rapid method for the estimation of long chain aliphatic hydrocarbons from the leaves of C. quadrangularis using HPTLC technique. Methods: Precoated silica gel 60 F254 plates were used as stationary phase. The mobile phase used was hexane (100 %. The detection of spots was carried out using berberine sulphate as detecting reagent. Results: The method was validated in terms of linearity, sensitivity, accuracy, and precision. Linearity range was found to be 2-10 µg/mL, limit of detection 0.127 µg/mL, and limit of quantification 0.384 µg/mL. Conclusions: A novel, simple, accurate, precise and sensitive HPTLC method has been developed and validated for the estimation of long chain aliphatic hydrocarbons obtained from the leaves of C. quadrangularis Linn.

  13. Chlorine

    Science.gov (United States)

    ... but it is also used to make pesticides (insect killers), rubber, and solvents. Chlorine is used in ... the following signs and symptoms may develop: Blurred vision Burning pain, redness, and blisters on the skin ...

  14. Advances in longer-chain aliphatic olefins metathesis%长碳链烯烃歧化研究进展

    Institute of Scientific and Technical Information of China (English)

    郑敏; 陈胜利; 袁桂梅; 王雪莲; 桑磊; 尤菊; 张军辉

    2012-01-01

    The research of C4-olefin to produce propylene was the emphasis of aliphatic olefin metathesis technology,but attentions were also paid to longer-chain aliphatic olefins metathesis reaction.The progress of the metathesis reaction of longer-chain aliphatic olefins over rhenium based catalysis,molybdenum based catalysis and tungsten based catalysis were introduced.The study of longer-chain olefin metathesis over tungsten based catalyst,including the optimal operating condition of 1-hexene self-metathesis,1-heptene self-metathesis and 1-octene self-metathesis.The effect of pretreatment on metathesis performance of tungsten based catalyst is primarily introduced.Moreover,the studies of deactivation of metathesis catalyst by oxygenate poisoning and deactivation of tungsten based catalyst by coke formation are also introduced.%目前,虽然直链烯烃歧化研究的重点仍是碳四烯烃歧化制丙烯技术,但是长碳链烯烃歧化研究已开始引起人们的重视。本文介绍了铼基催化剂、钼基催化剂和钨基催化剂催化长碳链烯烃歧化反应的研究进展。重点介绍了钨基催化剂上长碳链歧化研究状况,分别介绍了钨基催化剂上1-己烯自歧化、1-庚烯自歧化、1-辛烯自歧化的最优工艺条件研究以及预处理条件对钨基催化剂歧化性能的影响。同时分别介绍了含氧化合物对歧化催化剂中毒失活的研究以及钨基催化剂上结焦失活的研究状况。

  15. Influence of the sterol aliphatic side chain on membrane properties: a molecular dynamics study.

    Science.gov (United States)

    Robalo, João R; Ramalho, J P Prates; Huster, Daniel; Loura, Luís M S

    2015-09-21

    Following a recent experimental investigation of the effect of the length of the alkyl side chain in a series of cholesterol analogues (Angew. Chem., Int. Ed., 2013, 52, 12848-12851), we report here an atomistic molecular dynamics characterization of the behaviour of methyl-branched side chain sterols (iso series) in POPC bilayers. The studied sterols included androstenol (i-C0-sterol) and cholesterol (i-C8-sterol), as well as four other derivatives (i-C5, i-C10, i-C12 and i-C14-sterol). For each sterol, both subtle local effects and more substantial differential alterations of membrane properties along the iso series were investigated. The location and orientation of the tetracyclic ring system is almost identical in all compounds. Among all the studied sterols, cholesterol is the sterol that presents the best matching with the hydrophobic length of POPC acyl chains, whereas longer-chained sterols interdigitate into the opposing membrane leaflet. In accordance with the experimental observations, a maximal ordering effect is observed for intermediate sterol chain length (i-C5, cholesterol, i-C10). Only for these sterols a preferential interaction with the saturated sn-1 chain of POPC (compared to the unsaturated sn-2 chain) was observed, but not for either shorter or longer-chained derivatives. This work highlights the importance of the sterol alkyl chain in the modulation of membrane properties and lateral organization in biological membranes.

  16. Synthesis and characterization of soluble, blue-fluorescent polyamides and polyimides containing substituted p-terphenyl as well as long aliphatic segments in the main chain

    NARCIS (Netherlands)

    Mikroyannidis, JA; Tsivgoulis, GM

    1999-01-01

    A novel class of semiflexible polyamides and polyimides bearing substituted p-terphenyl as well as long aliphatic segments in the main chain were synthesized through pyrylium salts. Characterization of polymers was accomplished by inherent viscosity, elemental analysis, FT-IR, NMR, UV-vis luminescen

  17. Chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Talmage, Sylvia Smith [ORNL

    2009-01-01

    Following a brief description of the use of chlorine as a chemical warfare agent in World War I, this chapter summarizes physical and chemical data and recent clinical and controlled laboratory studies on the irritant and lethal effects of chlorine. The mechanism of toxicity for both irritation and lethal effects is described. The mathematical relationship between concentration and exposure duration for a set endpoint is given for both an irritancy response and mortality. This information can be used to assist in time-scaling for the set endpoint to other exposure durations. Risk assessment addresses the potential for greater effects in sensitive populations such as asthmatics. A concentration of 0.5 ppm for up to 8 hours is a no-adverse-effect concentration in most sensitive subjects; whereas, a concentration of 1.0 ppm induces some sensory irritation and transient changes in respiratory tract airflow parameters. Treatment and intervention of exposed individuals is dependent upon symptoms

  18. [Contamination characteristics of short-chain chlorinated paraffins in edible fish of Shanghai].

    Science.gov (United States)

    Jiang, Guo; Chen, Lai-guo; He, Qiu-sheng; Meng, Xiang-zhou; Feng, Yong-bin; Huang, Yu-mei; Tang, Cai-ming

    2013-09-01

    According to the local habit of eating fish, in a total of 68 samples, 8 kinds of different trophic levels of edible fish collected in Shanghai were determined in terms of concentration and distribution profile of short chain chlorinated paraffin (SCCPs) in muscles to investigate the pollution status of SCCPs in edible fish from the Yangtze River Delta region. The results indicated that the concentrations (dw) of SCCPs in edible fish were in the range of 36-801 ng x g(-1). With the increase in carbon chain length, the concentration of SCCPs decreased. In addition, lower chlorinated (Cl6-Cl8) and shorter chain (Cl10, C11) congeners were the dominant chlorine and carbon homologues groups, respectively, contributing a total relative abundance of 61.46%-82.50% to the total abundance of SCCPs. The levels of SCCPs in fish of Shanghai were in the medium level worldwide, and the distribution pattern was in line with those of the domestic and foreign studies.

  19. Effect of a long chain aliphatic alkohols on growth. gas exchange and assimilate parlitioning in radish plant

    Directory of Open Access Journals (Sweden)

    Zbyszek K. Blamowski

    2013-12-01

    Full Text Available In pot experiments the influence of long chain aliphatic alcohols (hexacosanol - HEXA, octacosanol - OCTA and triacontanol - TRIA, which were used in concentration O.00l mg·dm3 , on growth, assimilate partitioning and gas exchange of radish plants cv. "Krakowianka" and "Sopel lodu" were studied. The received results showed that triacontanol was characterized by higher physiological activity than remaining alcohols. TRIA significantly increased yield of mass, as well as it changed the pattern of distribution of assimilates in plants. Under its influence the rate of mass of leaves to mass of storage organs decreased as well as the share of mass of leaves in the total mass of both plant cultivars. TRIA stimulated the rate of net photosynthesis (Pn, howewer, it did not influence the other detennined gas exchange parameters: substomatal concentration of CO2 (ci, stomatal conductance for water vapour (gs and rate of transpiration (Tr. Remaining alcohols (HEXA and OCFA did not any influence on growth of plants and their gas exchange but only on distribution of biomass.

  20. New bispyrazoline derivatives built around aliphatic chains: Synthesis, characterization and antimicrobial studies

    Indian Academy of Sciences (India)

    Mohamad Yusuf; Payal Jain

    2013-01-01

    The bispyrazolines 3a-3h built around the alkyl chains of varying lengths have been synthesized from the cyclization reactions of bischalcones with phenyl hydrazine. The bischalcones 2a-2h were obtained from the Claisen-Schmidt reactions of acetophenone with various bisaldehydes 1a-1h. The intermediate bischalcones and final bisheterocyclic compounds have been characterized by means of IR, 1H-NMR, 13C-NMR, Mass (ESI) and elemental analysis. The antibacterial and antifungal activities of the synthesized compounds were also evaluated against the Klubsellia pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillius subtilis and Aspergillius janus, Aspergillus niger and Pencillium glabrum, respectively. The antimicrobial behaviour of the bispyrazolines 3a-3h is found to be dependent on the length of internal spacer unit.

  1. Synthesis, characterisation and drug release properties of microspheres of polystyrene with aliphatic polyester side-chains.

    Science.gov (United States)

    Kukut, Manolya; Karal-Yilmaz, Oksan; Yagci, Yusuf

    2014-01-01

    A series of graft copolymers consisting of polystyrene backbone with biocompatible side chains based on (co)polymers of l-lactic acid and glycolic acid were synthesised by combination two controlled polymerisations, namely, nitroxide mediated radical polymerisation (NMRP) and ring opening polymerisation (ROP) with "Click" chemistry. The main goal of this work was to design new biodegradable microspheres using obtained graft copolymers for long-term sustained release of imatinib mesylate (IMM) as a model drug. The IMM loaded microspheres of the graft copolymers, polystyrene-g-poly(lactide-co-glycolide) (PS-g-PLLGA), polystyrene-g-poly(lactic acid) (PS-g-PLLA) and poly(lactic-coglycolic acid) (PLLGA) were then prepared by a modified water-in-oil-in-water (w1/o/w2) double emulsion/solvent evaporation technique. The optimised microspheres were characterised by particle size, encapsulation efficiency, and surface morphology also; their degradation and release properties were studied in vitro. The degradation studies of three different types of microspheres showed that the PS backbone of the graft copolymers slows down the degradation rate compared to PLLGA.

  2. Synthesis of novel lanthanide acylpyrazolonato ligands with long aliphatic chains and immobilization of the Tb complex on the surface of silica pre-modified via hydrophobic interactions.

    Science.gov (United States)

    Pettinari, C; Marchetti, F; Pettinari, R; Belousov, Y A; Taydakov, I V; Krasnobrov, V D; Petukhov, D I; Drozdov, A A

    2015-09-01

    Five new complexes Ln(Q(C17))3(H2O)(Solv) (Ln = Y, Solv = H2O, Ln = Tb, Dy, Sm or Eu, Solv = EtOH) were synthesized with the acylpyrazolonato ligand Q(C17) bearing a long aliphatic C17H35 chain in the acyl moiety, and the crystal structure of Y(Q(C17))3(H2O)2 shows the three aliphatic chains from the coordinated ligands positioned in the same direction, affording plane layers built by Y(Q(C17))3(H2O)2 molecules connected through H-bonding interactions. The layers are stitched to each other like in "hook & loop" tapes. Luminescence of complexes was determined and the complex Tb(Q(C17))3(H2O)(EtOH) was immobilized on the surface of silica preprocessed using a C17H35CONH(CH2)3Si(OEt)3 reagent via hydrophobic interactions of long aliphatic chains. Luminescent properties and micromorphology of the obtained hybrid particles and hybrid films were investigated. Intensive green emission of the complex retains after grafting onto the silica surface. Inclusion of the complex on the surface of silica materials occurs as separate molecules, after the disruption of the H-bonding network present in the crystalline phase of the pure terbium sample.

  3. Study on biodegradable aromatic/aliphatic copolyesters

    Energy Technology Data Exchange (ETDEWEB)

    Yiwang Chen; Licheng Tan; Lie Chen; Yan, Yang; Xiaofeng Wang [Nanchang University, Nanchang (China). School of Materials Science and Engineering. Inst. of Polymer Materials]. E-mail: ywchen@ncu.edu.cn

    2008-04-15

    Progress on biodegradable aromatic/aliphatic copolyesters based on aliphatic and aromatic diacids, diols and ester monomers was reviewed. The aromatic/aliphatic copolyesters combined excellent mechanical properties with biodegradability. Physical properties and biodegradability of copolyesters varied with chain length of the aliphatic polyester segment and atacticity of copolyesters. The process ability of copolyesters could be improved significantly after incorporating a stiff chain segment through copolymerization of aliphatic polyesters with an aromatic liquid crystal element. The aromatic/aliphatic copolyesters as a new type of biodegradable materials could replace some general plastics in certain applications, namely biomedical and environmental friendly fields. (author)

  4. Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

    OpenAIRE

    Marijanović-Rajčić, M.; Senta, A.

    2008-01-01

    The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1). The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašna...

  5. Toxicokinetics of short-chain chlorinated paraffins in Sprague-Dawley rats following single oral administration.

    Science.gov (United States)

    Geng, Ningbo; Zhang, Haijun; Xing, Liguo; Gao, Yuan; Zhang, Baoqin; Wang, Feidi; Ren, Xiaoqian; Chen, Jiping

    2016-02-01

    Short-chain chlorinated paraffins (SCCPs) have attracted considerable attention for their characteristic of persistent organic pollutants. However, very limited information is available for their toxicokinetic characteristics, limiting the evaluation of their health risks. In this study, we performed a toxicokinetics study to explore the absorption and excretion processes of SCCPs (a mixture of C10-, C11-, C12- and C13-CPs) after a single oral administration to the Sprague-Dawley rats. The toxicokinetic results showed that peak blood concentration of total SCCPs was attained at 2.8 day with Cmax value of 2.3 mg L(-1). The half-lives of total SCCPs in blood for the absorption t1/2 (ka), distribution t1/2 (α) and elimination phases t1/2 (β) were calculated to be 1.0, 1.7 and 6.6 days, respectively. During the 28 days post-dosing, about 27.9% and 3.5% of orally administrated SCCPs were excreted through feces and urine without metabolism, respectively. Congener group abundance profiles indicate a relative increase of Cl5-SCCPs in blood and urine in the elimination stage, and a higher accumulation of Cl8-10-SCCPs in feces. The distribution discrepancies of SCCPs congener groups in blood and excreta were more dependent on chlorine contents than on carbon chain lengths.

  6. The difluoromethylene (CF2) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF2 groups.

    Science.gov (United States)

    Wang, Yi; Callejo, Ricardo; Slawin, Alexandra M Z; O'Hagan, David

    2014-01-06

    The syntheses of palmitic acids and a nonadecane are reported with CF2 groups located 1,3 or 1,4 to each other along the aliphatic chain. Specifically 8,8,10,10- and 8,8,11,11-tetrafluorohexadecanoic acids (6b and 6c) are prepared as well as the singly modified analogue 8,8-difluorohexadecanoic acid (6a). Also 8,8,11,11-tetrafluorononadecane (27) is prepared as a pure hydrocarbon containing a 1,4-di-CF2 motif. The modified palmitic acids are characterized by differential scanning calorimetry (DSC) to determine melting points and phase behaviour relative to palmitic acid (62.5 °C). It emerges that 6c, with the CF2 groups placed 1,4- to each other, has a significantly higher melting point (89.9 °C) when compared to the other analogues and palmitic acid itself. It is a crystalline compound and the structure reveals an extended anti-zig-zag chain. Similarly 8,8,11,11-tetrafluorononadecane (27) adopts an extended anti-zig-zag structure. This is rationalized by dipolar relaxation between the two CF2 groups placed 1,4 to each other in the extended anti-zig-zag chain and suggests a design modification for long chain aliphatics which can introduce conformational stability.

  7. THE EFFECT OF SULPHURIC ACID CONCENTRATION ON SOLVENT EXTRACTION OF ReO4 - BY THE LONG-CHAIN ALIPHATIC TERTIARY AMINES AND ALCOHOLS

    Directory of Open Access Journals (Sweden)

    Aleksander G. Kasikov

    2010-06-01

    Full Text Available The effect of sulphuric acid concentration on solvent extraction of ReO4- by the long-chain aliphatic tertiary amines and alcohols in a wide range of H2SO4 concentrations in initial solutions is discussed. It has been established that the influence of the sulphuric acid concentration on rhenium solvent extraction is largely due to the extraction process mechanism. In the case of the anion-exchange mechanism, ReO4- is best extracted from weakly acidic solutions, whereas when the hydrate-solvate mechanism takes place – from solutions containing 4-7 mole/l H2SO4.

  8. Emission inventory and provincial distribution of short-chain chlorinated paraffins in China.

    Science.gov (United States)

    Zhang, Boya; Zhao, Bu; Xu, Chun; Zhang, Jianbo

    2017-03-01

    Chlorinated paraffins (CPs) are used as flame retardants, plasticizers, and metalworking fluids, which have varying contents of toxic short-chain chlorinated paraffins (SCCPs). Based on the study of several relevant production and consumption sectors, this paper classifies the consumption of CPs among sectors and provides an emission inventory and the provincial emission distribution of SCCPs in China in 2010-2014 based on the consumption patterns and emission factors of each sector. The total emissions of SCCPs in China in 2014 were 3083.88tons, with emissions to the atmosphere and water accounting for 894.81tons and 2189.07tons, respectively. The largest emission source was from metalworking fluids, with total emissions of 2459.12tons, of which 756.65tons went to the atmosphere and 1702.47tons to water. Our results show that SCCP emissions were mainly concentrated in the eastern, more developed regions and that Jiangsu Province was the biggest producer in China, with total emissions of 1853.06tons, of which 562.61tons were to the atmosphere and 1290.46tons to water.

  9. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 72, Revision 1 (FGE.72Rev1): Consideration of aliphatic, branched-chain saturated and unsaturated alcohols, aldehydes, acids, and related esters, evaluated by the JECFA (61st meeting) structurally related to branched- and straight-chain unsaturated carboxylic acids, esters of these and straight-chain aliphatic saturated alcohols evaluated by EFSA in FGE.05Rev2

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz;

    evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of 23 aliphatic branched-chain saturated and unsaturated alcohols, aldehydes, acids and related esters, evaluated by the JECFA at their 61st meeting. This revision is made due...

  10. Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

    Directory of Open Access Journals (Sweden)

    Marijanović-Rajčić, M.

    2008-01-01

    Full Text Available The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1. The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašnak spring that is contaminated with volatile chlorinated short-chain hydrocarbons.Drinking water samples were taken from 3 private wells and 1 public water-supply system situated in 3 Zagreb suburbs - Pešćenica, Trnje, and Trešnjevka. The sampling was carried out during 2003 and was undertaken on a seasonal basis. Short-chain chlorinated hydrocarbons - 1,1,1-trichloroethane, carbon tetrachloride, 1,1,2-trichloroethene and 1,1,2,2-tetrachloroethene - were determined by gas chromatography, following "liquid-liquid extraction" in pentane. For that purpose, we applied the gas chromatograph equipped with an electron-capture detector, thermo-programmable operations, and a suitable capillary column. The technique applied was that of split-injection.The groundwater of the City of Zagreb was found to be contaminated with volatile chlorinated hydrocarbons. The concentration level of 1,1,1-trichloroethane, determined in most of the samples, was found to be low (Fig. 2. On the other hand, 1,1,2-trichloroethene was present in all samples in concentrations of about 1 µg l-1- (Fig. 3. Only the drinking water samples taken from private wells in the suburb of Trnje contained somewhat higher mass concentrations of 1,1,1-trichloroethane, with the peak value of 19.03 µg l-1, measured in the winter season. In the samples taken from private wells in Trnje, the mass concentrations of 1,1,2,2-tetrachloroethene rangedfrom 15.30 µg l-1 to 18.65 µg l-1, as measured in autumn

  11. Novel platinum(II) complexes of long chain aliphatic diamine ligands with oxalato as the leaving group: Comparative cytotoxic activity relative to chloride precursors

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Heveline; Barra, Carolina V.; Rocha, Fillipe V.; Fontes, Ana Paula S. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Quimica; Lopes, Miriam T.P. [Universidade Federal deMinas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Farmacologia; Frezard, Frederic, E-mail: frezard@icb.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisiologia e Biofisica

    2010-07-01

    Platinum complexes play an important role in the development of anticancer drugs. Their cytotoxicity can be influenced by the nature of the leaving ligands, due to the hydrolysis reaction that occurs prior to the binding of the platinum complex to DNA. Also, non-leaving groups such as lipophilic diamines may affect cellular uptake. In this work, we describe the synthesis of platinum(II) complexes having oxalato and long chain aliphatic N-alkyl ethylenediamines as ligands. The products were characterized by elemental analyses, infrared spectroscopy and {sup 1}H, {sup 13}C and {sup 195}Pt NMR spectroscopy. Biological activity was assessed against tumor cell lines (A{sub 549}, B16-F1, B16-F10, MDA-MB-231) and non-tumor cell lines (BHK-21 and CHO). The length of the carbon chain affects the cytotoxicity and the oxalato complexes were less cytotoxic than the respective chloride-containing analogues. (author)

  12. Medium-chain chlorinated paraffins (MCCPs): a review of bioaccumulation potential in the aquatic environment.

    Science.gov (United States)

    Thompson, Roy; Vaughan, Martin

    2014-01-01

    Chlorinated paraffins (CPs) are high molecular weight organochlorine compounds that have been used in a variety of industrial applications for many years. Medium-chain chlorinated paraffins (MCCPs) (CAS 85535-85-9; Alkanes, C14-17 , chloro) are currently under investigation as potential persistent bioaccumulative toxic (PBT) compounds. In this article, the bioaccumulation potential of MCCPs is assessed using a tiered framework proposed after a recent Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop in 2008. The framework proposes the use of physicochemical properties and modeling assessment, bioconcentration/bioaccumulation (BCF/BAF) assessment, biomagnification (BMF) assessment, and trophic magnification factor (TMF) assessment. It is hoped that use of this framework could harmonize and improve the efficiency and effectiveness of the chemical substance evaluation screening process for PBT properties. When applied to MCCPs, the following conclusions were made: empirical physiochemical data is available negating the use of models; laboratory BCFs range from 1000 to 15 000 (growth-corrected lipid normalized values) for 2 MCCP structures; field BAFs were an order of magnitude higher than the trigger criterion for "B status possible"; although results may not meet acceptance criteria for field studies, laboratory-derived BMFs for a number of C14-17 chlorinated alkanes were less than the trigger value of 1 (based on whole-body concentrations) whereas field-derived BMFs were less than 1 (based on lipid corrected values [generally used for field data] excluding one measure for sculpin, [Cottus cognatus]-Diporeia that was based on only one detectable sample); and finally, TMFs were less than the trigger criterion value of 1, which are considered the most convincing evidence for bioaccumulative properties of a compound and the "Gold Standard" measure of bioaccumulation. This article also discusses the uncertainties surrounding the published data

  13. Global production, use, and emission volumes of short-chain chlorinated paraffins - A minimum scenario.

    Science.gov (United States)

    Glüge, Juliane; Wang, Zhanyun; Bogdal, Christian; Scheringer, Martin; Hungerbühler, Konrad

    2016-12-15

    Short-chain chlorinated paraffins (SCCPs) show high persistence, bioaccumulation potential, and toxicity (PBT properties). Consequently, restrictions on production and use have been enforced in several countries/regions. The Stockholm Convention on Persistent Organic Pollutants recognized the PBT properties and long-range transport potential of SCCPs in 2015 and is now evaluating a possible global phase-out or restrictions. In this context, it is relevant to know which countries are producing/using SCCPs and in which amounts, and which applications contribute most to their environmental emissions. To provide a first comprehensive overview, we review and integrate all publicly available data on the global production and use of both chlorinated paraffins (CPs) as a whole and specifically SCCPs. Considerable amount of data on production/use of CPs and SCCPs are missing. Based on the available data and reported emission factors, we estimate the past and current worldwide SCCP emissions from individual applications. Using the available data as a minimum scenario, we conclude: (i) SCCP production and use is increasing, with the current worldwide production volume being 165,000t/year at least, whereas the global production of total CPs exceeds 1milliont/year. (ii) The worldwide release of SCCPs from their production and use to air, surface water, and soil between 1935 and 2012 has been in the range of 1690-41,400t, 1660-105,000t, and 9460-81,000t, respectively. (iii) The SCCP manufacture and use in PVC, the use in metal working applications and sealants/adhesives, and the use in plastics and rubber contribute most to the emissions to air, surface water, and soil. Thus, the decrease in the environmental emissions of SCCPs requires reduction of SCCP use in (almost) all applications. (iv) Emissions due to the disposal of waste SCCPs cannot be accurately estimated, because relevant information is missing. Instead, we conduct a scenario analysis to provide some insights into

  14. Solid-phase microextraction for the analysis of short-chain chlorinated paraffins in water samples.

    Science.gov (United States)

    Castells, P; Santos, F J; Galceran, M T

    2003-01-10

    A novel solid-phase microextraction (SPME) method coupled to gas chromatography with electron capture detection (GC-ECD) was developed as an alternative to liquid-liquid and solid-phase extraction for the analysis of short-chain chlorinated paraffins (SCCPs) in water samples. The extraction efficiency of five different commercially available fibres was evaluated and the 100-microm polydimethylsiloxane coating was the most suitable for the absorption of the SCCPs. Optimisation of several SPME parameters, such as extraction time and temperature, ionic strength and desorption time, was performed. Quality parameters were established using Milli-Q, tap water and river water. Linearity ranged between 0.06 and 6 microg l(-1) for spiked Milli-Q water and between 0.6 and 6 microg l(-1) for natural waters. The precision of the SPME-GC-ECD method for the three aqueous matrices was similar and gave relative standard deviations (RSD) between 12 and 14%. The limit of detection (LOD) was 0.02 microg l(-1) for Milli-Q water and 0.3 microg l(-1) for both tap water and river water. The optimised SPME-GC-ECD method was successfully applied to the determination of SCCPs in river water samples.

  15. Endosulfan, pentachlorobenzene and short-chain chlorinated paraffins in background soils from Western Europe.

    Science.gov (United States)

    Halse, Anne Karine; Schlabach, Martin; Schuster, Jasmin K; Jones, Kevin C; Steinnes, Eiliv; Breivik, Knut

    2015-01-01

    Soils are major reservoirs for many persistent organic pollutants (POPs). In this study, "newly" regulated POPs i.e. Σendosulfans (α-endosulfan, β-endosulfan, endosulfan sulfate), pentachlorobenzene (PeCB), and short-chain chlorinated paraffins (SCCPs) were determined in background samples from woodland (WL) and grassland (GL) surface soil, collected along an existing latitudinal UK-Norway transect. Statistical analysis, complemented with plots showing the predicted equilibrium distribution and mobility potential, was then explored to discuss factors controlling their spatial distribution. SCCPs were detected with the highest average concentrations (35 ± 100 ng/g soil organic matter (SOM)), followed by Σendosulfans (3 ± 3 ng/g SOM) and PeCB (1 ± 1 ng/g SOM). PeCB and Σendosulfans share many similarities in their distribution in these background soils as well as with several legacy POPs. A steep decline in concentrations of SCCPs with increasing latitude indicates that their occurrence is dictated by proximity to source regions, while concentrations of Σendosulfans peaked in regions experiencing elevated precipitation rates.

  16. Short-Chain Chlorinated Paraffins in Zurich, Switzerland--Atmospheric Concentrations and Emissions.

    Science.gov (United States)

    Diefenbacher, Pascal S; Bogdal, Christian; Gerecke, Andreas C; Glüge, Juliane; Schmid, Peter; Scheringer, Martin; Hungerbühler, Konrad

    2015-08-18

    Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m(-3) (spring 2011) and 1.1 to 42 ng·m(-3) (spring 2013) with medians of 4.3 and 2.7 ng·m(-3), respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218-321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries.

  17. Stir bar sorptive extraction for the analysis of short-chain chlorinated paraffins in water.

    Science.gov (United States)

    Llorca-Porcel, Julio; Martínez-Soriano, Esther; Valor, Ignacio

    2009-05-01

    An optimised method using stir bar sorptive extraction (SBSE) and a thermal desorption-GC-electron capture detector (GC-ECD) for the determination of short-chain chlorinated paraffins from water samples was developed. Recoveries near to 100% were obtained by using 20 mm x 0.5 mm (length x film thickness) PDMS commercial stir bars from 200 mL spiked water samples and 20% methanol addition with an extraction period of 24 h. Method sensitivity, linearity and precision were evaluated for surface water and wastewater spiked samples. A LOD of 0.03 and 0.04 microg/L was calculated for surface and wastewater, respectively. The precision of the method given as an RSD was below 20% for both matrices. The developed method was applied for the analysis of two real samples from a contaminated river and a wastewater treatment plant. Results were in accordance with those obtained using a previously developed method based on solid phase microextraction (SPME).

  18. Gridded emission inventory of short-chain chlorinated paraffins and its validation in China.

    Science.gov (United States)

    Jiang, Wanyanhan; Huang, Tao; Mao, Xiaoxuan; Wang, Li; Zhao, Yuan; Jia, Chenhui; Wang, Yanan; Gao, Hong; Ma, Jianmin

    2017-01-01

    China produces approximately 20%-30% of the total global chlorinated paraffins (CPs). The establishment of a short-chain CP (SCCP) emission inventory is a significant step toward risk assessment and regulation of SCCPs in China and throughout the globe. This study developed a gridded SCCPs emission inventory with a 1/4° longitude by 1/4° latitude resolution from 2008 to 2012 for China, which was based on the total annual CPs emissions for the nation. The total national SCCPs emission during this 5-year period was 5651.5 tons. An additive in metal cutting fluids was a major emission source in China, contributing 2680.2 tons to the total atmospheric emissions of SCCPs from 2008 to 2012, followed by the production of CPs (2281.8 tons), plasticizers (514.3 tons), flame retardants (108.6 tons), and net import (66.6 tons). Most of these emission sources are located along the eastern seaboard of China and southern China. A coupled atmospheric transport model was employed to simulate environmental contamination by SCCPs using the gridded emission inventory of SCCPs from 2008 to 2012 as the model initial conditions. Simulated atmospheric and soil concentrations were compared with field monitoring data to validate the emission inventory. The results showed good consistency between modeled and field sampling data, supporting the reliability and credibility of the gridded SCCPs emission inventory that was developed in the present study.

  19. Short-chain chlorinated paraffins (SCCPs) in surface soil from a background area in China: occurrence, distribution, and congener profiles.

    Science.gov (United States)

    Wang, Xue-Tong; Zhang, Yuan; Miao, Yi; Ma, Ling-Ling; Li, Yuan-Cheng; Chang, Yue-Ya; Wu, Ming-Hong

    2013-07-01

    Short-chain chlorinated paraffins (SCCPs) are extremely complex technical mixtures of polychlorinated n-alkanes with carbon chain lengths from C10 to C13 and chlorine content between 49 and 70%. SCCPs are under consideration for inclusion in the Stockholm Convention on persistent organic pollutants. SCCPs have been used extensively in industrial production, but little is known about the pollution level in soil environment in China. In this study, levels and distribution of SCCPs in soil samples from Chongming Island were analyzed. Concentrations of total SCCPs in soil samples ranged from 0.42 to 420 ng g(-1), with a median of 9.6 ng g(-1). The ubiquitous occurrence of SCCPs in Chongming Island implied that long-range atmospheric transport and soil-air exchange may be the most important pathways for SCCP contamination in the background area. The localized SCCP contamination could be derived from an unidentified source. Hierarchical cluster analysis indicated that C13- and C11-congeners were predominant in most soils and C10- and C12-congeners dominated in the remaining soils. Cl7- and Cl8-congeners were on the average the most dominant chlorine congeners in nearly all soils. Principal component analysis suggested that the separation of even and odd carbon chain congeners occurred during long-range atmospheric transport and aging in soil in the study area.

  20. Relative developmental toxicity of short-chain chlorinated paraffins in Zebrafish (Danio rerio) embryos.

    Science.gov (United States)

    Liu, Lihua; Li, Yifan; Coelhan, Mehmet; Chan, Hing Man; Ma, Wanli; Liu, Liyan

    2016-12-01

    Short-chain chlorinated paraffins (SCCPs) are ubiquitous in the environment and might cause adverse environmental and human health effects. Little is known about the relative toxicity of different SCCP compounds especially during development. The objective of this study was to characterize and compare effects of seven SCCP groups at environmentally relevant levels, using a zebrafish (Danio rerio) model. Observations on malformation, survival rates at 96 h post fertilization (hpf), and hatching rates at 72 hpf indicated that the C10- groups (C10H18Cl4, 1,2,5,6,9,10-C10H16Cl6 and C10H15Cl7) were more toxic than the C12- groups (C12H22Cl4, C12H19Cl7 and 1,1,1,3,10,12,12,12-C12H18Cl8) and Cereclor 63L. The C10- groups were also more potent than C12- groups and Cereclor 63L in decreasing thyroid hormone levels. Among the three compounds within the C10- group, the compounds with less chlorine content had stronger effects on sub-lethal malformations but less effects on triiodothyronine (T3) and tetraiodothyronine (T4). Only C10H18Cl4 significantly decreased the mRNA expression of tyr, ttr, dio2 and dio3 at a dose-dependent manner suggesting that the specific mode of actions differ with different congeners. The mechanisms of disruption of thyroid status by different SCCPs could be different. C10H18Cl4 might inhibit T3 production through the inhibition effect on dio2. These results indicate that SCCP exposure could alter gene expression in the hypothalamic-pituitary-thyroid (HPT) axis and thyroid hormone levels. The mechanisms of disruption of thyroid status by different SCCPs could be different. Our results on the relative developmental toxicities of SCCPs will be useful to reach a better understanding of SCCP toxicity supporting environmental risk evaluation and regulation and used as a guidance for environmental monitoring of SCCPs in the future.

  1. Short-chain chlorinated paraffins in cooking oil and related products from China.

    Science.gov (United States)

    Cao, Yang; Harada, Kouji H; Liu, Wanyang; Yan, Junxia; Zhao, Can; Niisoe, Tamon; Adachi, Ayumu; Fujii, Yukiko; Nouda, Chihiro; Takasuga, Takumi; Koizumi, Akio

    2015-11-01

    Short-chain chlorinated paraffins (SCCPs) are emerging persistent organic pollutants. It has been found that dietary intakes of SCCPs in China have recently increased and are now higher than in Japan and Korea. The contribution of cooking oil to dietary exposure to SCCPs in China was evaluated by analyzing SCCPs in cooking oil, raw seeds used to produce cooking oil, and fried confectionery products collected in China in 2010 and 2012. Detectable amounts of SCCP homologs were found in 48 out of the 49 cooking oil samples analyzed, and the SCCP concentrations varied widely, from <9 to 7500 ng g(-1). Estimated dietary intakes of total SCCPs in cooking oil ranged from <0.78 to 38 μg d(-1). The estimated dietary intake of SCCPs was relatively high (mean 14.8 μg d(-1)) for residents of Beijing. Fried confectionery was found to contain SCCP concentrations of 11-1000 ng g(-1). Cooking oil might therefore be one of the sources of SCCPs to Chinese diets. SCCPs were also detected in raw seeds used to produce cooking oil, but the concentrations varied widely. The SCCP homolog patterns in the raw seed and cooking oil samples were different, implying that the seeds used to produce the oil (and therefore the soil on which the seeds were produced) were unlikely to be the sources of SCCPs in cooking oil. Further investigations are needed to determine the routes through which cooking oil becomes contaminated with SCCPs during the production and processing of the oil.

  2. Lactational exposure to short-chain chlorinated paraffins in China, Korea, and Japan.

    Science.gov (United States)

    Cao, Yang; Harada, Kouji H; Hitomi, Toshiaki; Niisoe, Tamon; Wang, Peiyu; Shi, Yuhui; Yang, Hye-Ran; Takasuga, Takumi; Koizumi, Akio

    2017-04-01

    To investigate short-chain chlorinated paraffin (SCCP) levels in human breast milk, pooled breast milk samples (BMSs) collected between 2007 and 2010 from Chinese (Beijing, n = 17), Korean (Seoul, Busan, n = 16), and Japanese (Kyoto, Sendai, n = 44) women were analyzed. SCCPs found in air samples in Beijing (n = 4, in 2008) were also analyzed and compared with BMSs to estimate the possible source of contamination in Beijing. The electron-capture negative ionization method demonstrated the different sensitivities for SCCPs, and pentachlorinated alkanes had the highest method detection limit (MDL) among congeners. In Beijing, SCCPs were detected in 8 of 17 pooled BMSs at concentrations more than the highest MDL of each homolog. The total SCCP concentration ranged from below the MDL to 54 ng g(-1) lipid weight. Among the SCCP homologs, polychlorinated tridecanes were most frequently detected in Beijing. In Korea and Japan, no samples contained detectable total SCCP concentrations at more than the highest MDL. In Seoul, only two samples showed trace levels of polychlorinated undecanes. In Kyoto and Sendai, congeners of polychlorinated dodecanes were most frequently detected. C10 components were the major contributors to the SCCPs in the atmosphere of Beijing. Congener profiles in breast milk in Beijing provided a clear contrast to the profiles found in food and air. The unique congener profiles necessitate the monitoring of breast milk for exposure of infants to SCCPs. The calculated mean exposure of SCCPs in 1-year-olds in China was 337 ng (kg body weight)(-1) d(-1). These results demonstrate the body burden of SCCPs in the study areas and potential lactational exposure to SCCPs in Asian countries.

  3. Molecular structure stability of short-chain chlorinated paraffins (SCCPs): Evidence from lattice compatibility and Simha-Somcynsky theories

    Science.gov (United States)

    Yumak, A.; Boubaker, K.; Petkova, P.; Yahsi, U.

    2015-10-01

    In is known that short-chain chlorinated paraffins (SCCPs) are highly complex technical mixtures of polychlorinated n-alkanes with single chlorine content. Due to their physical properties (viscosity, flame resistance) they are used in many different applications, such as lubricant additives, metal processing, leather fat-liquoring, plastics softening, PVC plasticizing and flame retardants in paints, adhesives and sealants. SCCPs are studied here in terms of processing-linked molecular structure stability, under Simha and Somcynsky-EOS theory calculations and elements from Simha-Somcynsky-related Lattice Compatibility Theory. Analyses were carried out on 1-chloropropane, 2-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chloro 2-methylane, and 2-chloro 2-methylane as (SCCPs) universal representatives. This paper gives evidence to this stability and reviews the current state of knowledge and highlights the need for further research in order to improve future (SCCPs) monitoring efforts.

  4. Comparison of the Photovoltaic Characteristics and Nanostructure of Fullerenes Blended with Conjugated Polymers with Siloxane-Terminated and Branched Aliphatic Side Chains

    KAUST Repository

    Kim, Do Hwan

    2013-02-12

    All-organic bulk heterojunction solar cells based on blends of conjugated polymers with fullerenes have recently surpassed the 8% efficiency mark and are well on their way to the industrially relevant ∼15% threshold. Using a low band-gap conjugated polymer, we have recently shown that polymer side chain engineering can lead to dramatic improvement in the in-plane charge carrier mobility. In this article, we investigate the effectiveness of siloxy side chain derivatization in controlling the photovoltaic performance of polymer:[6,6]-phenyl-C[71]-butyric acid methyl ester (PC71BM) blends and hence its influence on charge transport in the out-of-plane direction relevant for organic solar cells. We find that, in neat blends, the photocurrent of the polymer with siloxy side chains (PII2T-Si) is 4 times greater than that in blends using the polymer with branched aliphatic side chains (PII2T-ref). This difference is due to a larger out-of-plane hole mobility for PII2T-Si brought about by a largely face-on crystallite orientation as well as more optimal nanoscale polymer:PC71BM mixing. However, upon incorporating a common processing additive, 1,8-diiodooctane (DIO), into the spin-casting blend solution and following optimization, the PII2T-ref:PC71BM OPV device performance undergoes a large improvement and becomes the better-performing device, almost independent of DIO concentration (>1%). We find that the precise amount of DIO plays a larger role in determining the efficiency of PII2T-Si:PC71BM, and even at its maximum, the device performance lags behind optimized PII2T-ref:PC71BM blends. Using a combination of atomic force microscopy and small- and wide-angle X-ray scattering, we are able to elucidate the morphological modifications associated with the DIO-induced changes in both the nanoscale morphology and the molecular packing in blend films. © 2012 American Chemical Society.

  5. Vortex-assisted liquid-liquid microextraction for the rapid screening of short-chain chlorinated paraffins in water.

    Science.gov (United States)

    Chang, Chia-Yu; Chung, Wu-Hsun; Ding, Wang-Hsien

    2016-01-01

    The rapid screening of trace levels of short-chain chlorinated paraffins in various aqueous samples was performed by a simple and reliable procedure based on vortex-assisted liquid-liquid microextraction combined with gas chromatography and electron capture negative ionization mass spectrometry. The optimal vortex-assisted liquid-liquid microextraction conditions for 20 mL water sample were as follows: extractant 400 μL of dichloromethane; vortex extraction time of 1 min at 2500 × g; centrifugation of 3 min at 5000 × g; and no ionic strength adjustment. Under the optimum conditions, the limit of quantitation was 0.05 μg/L. Precision, as indicated by relative standard deviations, was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was above 91%. The vortex-assisted liquid-liquid microextraction with gas chromatography and electron capture negative ionization mass spectrometry method was successfully applied to quantitatively extract short-chain chlorinated paraffins from samples of river water and the effluent of a wastewater treatment plant, and the concentrations ranged from 0.8 to 1.6 μg/L.

  6. Microwave-assisted extraction versus Soxhlet extraction for the analysis of short-chain chlorinated alkanes in sediments.

    Science.gov (United States)

    Parera, J; Santos, F J; Galceran, M T

    2004-08-13

    Microwave-assisted extraction (MAE) was evaluated as a possible alternative to Soxhlet extraction for analysing short-chain chlorinated alkanes (commonly called short-chain chlorinated paraffins, SCCPs) in river sediment samples, using gas chromatography coupled to negative chemical ionisation mass spectrometry. For MAE optimisation, several extraction parameters such as solvent extraction mixture, extraction time and extraction temperature were studied. Maximum extraction efficiencies for SCCPs (90%) and for 12 polychlorinated biphenyl (PCB) congeners (91-95%) were achieved using 5 g of sediment sample, 30 ml of n-hexane-acetone (1:1, v/v) as solvent extraction, and 15 min and 115 degrees C of extraction time and temperature, respectively. Activated Florisil was used to clean-up the extracts, allowing highly selective separation of SCCPs from other organic contaminants such as PCBs. MAE was compared with a conventional extraction technique such as Soxhlet and good agreement in the results was obtained. Quality parameters of the optimised MAE method such as run-to-run (R.S.D. 7%) and day-to-day precision (R.S.D. 9%) were determined using spiked river sediment samples, with LODs of 1.5 ng g(-1). This method was successfully applied to the analysis of SCCPs in river sediment samples at concentrations below the ng g(-1) level. O 2004 Elsevier B.V. All rights reserved.

  7. Long-chain aliphatic wax esters isolated from the sponge Chalinula saudensis (Demospongia along the Jeddah coast of the Red Sea

    Directory of Open Access Journals (Sweden)

    Abdulmohsin Al-Sofyani

    2011-03-01

    Full Text Available The sponge Chalinula saudensis, which occurs along the Jeddah coast, has only recently been isolated and identified. In this study, the total crude organic matter of the sponge was extracted by solvents. The total crude extract was further separated by partitioning it with hexane and water, then with water and chloroform, and finally with water and t-butanol. The chloroform layer was subjected to separation by preparative layer chromatography on silica. One fraction contained four long-chain fatty acid esters, C28H56O2, C30H60O2, C32H62O2 and C36H70 O2. The second ester, C30H60O2, has been identified in the fire corals Millepora dichotoma and Millepora platyphylla. The others have not previously been reported from marine organisms; however similar long-chain esters with different long aliphatic chains and with different molecular weights have been identified from other marine organisms. These compounds are normally waxy and their presence in Chalinula saudensis plays a vital role in the biosynthetic pathways. They also act as insulators against seasonal variations.A esponja Chalinula saudensis ocorre ao longo da costa de Jeddah, Arabia Saudita, mas apenas recentemente foi isolada e identificada. No presente estudo a matéria orgânica total da esponja foi extraída por solventes e o extrato foi separado por partição sucessiva através do emprego de hexano e água, clorofórmio e água e finalmente t-butanol e água. A camada contendo clorofórmio foi então separada por cromatografia em sílica. Os resultados mostraram a presença de ésteres de quatro ácidos graxos de cadeira longa (C28H56O2, C30H60O2, C32H62O2 e C36H70O2, sendo que o segundo deles foi também identificado nos corais Millepora dichotoma e Millepora platyphylla. Não se tem evidência da presença dos demais compostos em outros organismos marinhos, embora haja relatos para ésteres semelhantes de cadeia longa, mas contendo diferentes cadeias alifáticas e diferentes pesos

  8. High-Throughput Determination and Characterization of Short-, Medium-, and Long- Chain Chlorinated Paraffins in Human Blood.

    Science.gov (United States)

    Li, Tong; Wan, Yi; Gao, Shixiong; Wang, Beili; Hu, Jianying

    2017-02-22

    The industrial chlorinated paraffins (CPs) are comprised of short-chain (SCCPs), medium chain (MCCPs), and long chain (LCCPs) CPs. Although SCCPs and MCCPs are environmentally ubiquitous, little is known about CPs in humans. This study established a method for simultaneous determination of 261 SCCP, MCCP, and LCCP congener groups in one injection by reversed ultra-high-pressure liquid chromatography coupled with chlorine-enhanced electron spray ionization-quadrupole time-of-flight mass spectrometry. The method yielded good peak shapes, high sensitivities, and low co-eluted interferences for all examined CPs. LCCPs with carbon numbers of 21 to 27 were detected in their standard technical mixtures, and MCCPs and LCCPs impurities were detected in the LCCP and MCCP standard technical mixtures, respectively, causing quantification deviations when these mixtures were used for calibration. After considering these impurities' contribution to the total concentrations, the quantification accuracies for ∑SCCPs, ∑MCCPs, and ∑LCCPs ranged from 95.1±8.4% to 105.6±9.2% in the eight CP technical mixtures. The method was successfully applied to determine CPs in about 6 g human blood samples from a general population, and estimated ∑SCCP, ∑MCCP, and ∑LCCP concentrations to be 370-35,000, 130-3200, and 22-530 ng/g lipid weight (n=50), respectively. A comparison of blood and soil/air CP profiles from the same areas suggested a relatively higher potential for the accumulation of SCCPs, compared with MCCPs, in humans.

  9. Environmental behaviour of short-chain chlorinated paraffins in aquatic and terrestrial ecosystems of Ny-Ålesund and London Island, Svalbard, in the Arctic.

    Science.gov (United States)

    Li, Huijuan; Fu, Jianjie; Pan, Wenxiao; Wang, Pu; Li, Yingming; Zhang, Qinghua; Wang, Yawei; Zhang, Aiqian; Liang, Yong; Jiang, Guibin

    2017-07-15

    The environmental behaviour of short-chain chlorinated paraffins (SCCPs) was investigated in both aquatic and terrestrial ecosystems in the Arctic. The mean concentrations of SCCPs in the aquatic and terrestrial samples were 178.9ng/g dry weight (dw) and 157.2ng/g dw, respectively. Short carbon chain (C10) and less-chlorinated (Cl6) congener groups were predominant in the Arctic samples, accounting for 48.6% and 34.8% of the total SCCPs, respectively. The enrichment of lighter SCCP congener groups (i.e., fewer chlorine atoms with shorter carbon chain lengths) indicated that the fractionation process occurred during long-range transport. The biomagnification factor (BMF) was 0.46 from gammarid to cod, which indicated that the SCCPs did not biomagnify between these two species. The soil-vegetation bioaccumulation factor (BAF) of SCCPs was 29.9, and C13 and Cl7, 8 congener groups tended to accumulate in the terrestrial vegetation. Regression analysis (BAFs=10.9×#C+5.6×#Cl-125.2, R=0.53, P<0.01) showed that the number of carbon and chlorine atoms influenced the bioaccumulative behaviour of SCCPs and suggested that the number of carbon atoms had a greater influence on the BAFs of SCCPs in the terrestrial ecosystem than did the number of chlorine atoms.

  10. Evaluating the environmental fate of short-chain chlorinated paraffins (SCCPs) in the Nordic environment using a dynamic multimedia model.

    Science.gov (United States)

    Krogseth, Ingjerd S; Breivik, Knut; Arnot, Jon A; Wania, Frank; Borgen, Anders R; Schlabach, Martin

    2013-12-01

    Short chain chlorinated paraffins (SCCPs) raise concerns due to their potential for persistence, bioaccumulation, long-range transport and adverse effects. An understanding of their environmental fate remains limited, partly due to the complexity of the mixture. The purpose of this study was to evaluate whether a mechanistic, integrated, dynamic environmental fate and bioaccumulation multimedia model (CoZMoMAN) can reconcile what is known about environmental emissions and human exposure of SCCPs in the Nordic environment. Realistic SCCP emission scenarios, resolved by formula group, were estimated and used to predict the composition and concentrations of SCCPs in the environment and the human food chain. Emissions at the upper end of the estimated range resulted in predicted total concentrations that were often within a factor of 6 of observations. Similar model performance for a complex group of organic contaminants as for the well-known polychlorinated biphenyls strengthens the confidence in the CoZMoMAN model and implies a relatively good mechanistic understanding of the environmental fate of SCCPs. However, the degree of chlorination predicted for SCCPs in sediments, fish, and humans was higher than observed and poorly established environmental half-lives and biotransformation rate constants contributed to the uncertainties in the predicted composition and ∑SCCP concentrations. Improving prediction of the SCCP composition will also require better constrained estimates of the composition of SCCP emissions. There is, however, also large uncertainty and lack of coherence in the existing observations, and better model-measurement agreement will require improved analytical methods and more strategic sampling. More measurements of SCCP levels and compositions in samples from background regions are particularly important.

  11. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks.

  12. The quantification of short-chain chlorinated paraffins in sediment samples using comprehensive two-dimensional gas chromatography with μECD detection.

    Science.gov (United States)

    Muscalu, Alina M; Morse, Dave; Reiner, Eric J; Górecki, Tadeusz

    2017-03-01

    The analysis of persistent organic pollutants in environmental samples is a challenge due to the very large number of compounds with varying chemical and physical properties. Chlorinated paraffins (CPs) are complex mixtures of chlorinated n-alkanes with varying chain lengths (C10 to C30) and degree of chlorination (30 to 70% by weight). Their physical-chemical properties make these compounds persistent in the environment and able to bioaccumulate in living organisms. Comprehensive two-dimensional gas chromatography (GC × GC) coupled with micro-electron capture detection (μECD) was used to separate and quantify short-chain chlorinated paraffins (SCCP) in sediment samples. Distinct ordered bands were observed in the GC × GC chromatograms pointing to group separation. Using the Classification function of the ChromaTOF software, summary tables were generated to determine total area counts to set up multilevel-calibration curves for different technical mixes. Fortified sediment samples were analyzed by GC × GC-μECD with minimal extraction and cleanup. Recoveries ranged from 120 to 130%. To further validate the proposed method for the analysis of SCCPs, the laboratory participated in interlaboratory studies for the analysis of standards and sediment samples. The results showed recoveries between 75 and 95% and z-score values <2, demonstrating that the method is suitable for the analysis of SCCPs in soil/sediment samples. Graphical abstract Quantification of SCCPs by 2D-GC-μECD.

  13. Guided desaturation of unactivated aliphatics

    Science.gov (United States)

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

    2012-08-01

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

  14. Short-chain chlorinated paraffins in terrestrial bird species inhabiting an e-waste recycling site in South China.

    Science.gov (United States)

    Luo, Xiao-Jun; Sun, Yu-Xin; Wu, Jiang-Ping; Chen, She-Jun; Mai, Bi-Xian

    2015-03-01

    Short-chain chlorinated paraffins (SCCPs) are under review by the Stockholm Convention on Persistent Organic Pollutants. Currently, limited data are available about SCCPs in terrestrial organisms. In the present study, SCCP concentration in the muscles of seven terrestrial bird species (n = 38) inhabiting an e-waste recycling area in South China was determined. This concentration varied from 620 to 17,000 ng/g lipid. Resident birds accumulated significantly higher SCCP concentrations than migratory birds (p < 0.01). Trophic magnification was observed for migratory bird species but not for resident, which was attributed to high heterogeneity of SCCP in e-waste area. Two different homologue group patterns were observed in avian samples. The first pattern was found in five bird species dominated by C10 and C11 congeners, while the second was found in the remains, which show rather equal abundance of homologue groups. This may be caused by two sources of SCCPs (local and e-waste) in the study area.

  15. [Determination of short chain chlorinated paraffins in leather products by solid phase extraction coupled with gas chromatography-mass spectrometry].

    Science.gov (United States)

    Zhang, Weiya; Wan, Xin; Li, Lixia; Wang, Chengyun; Jin, Shupei; Xing, Jun

    2014-10-01

    The short chain chlorinated paraffins (SCCPs) are the additives frequently used in the leather production in China, but they have been put into the list of forbidden chemicals issued by European Union recently. In fact, there is not a commonly recognized method for the determination of the SCCPs in the leather products due to the serious matrix interferences from the leather products and the complex chemical structures of the SCCPs. A method of solid phase extraction coupled with gas chromatography-mass spectrometry (SPE-GC-MS) was established for the determination of the SCCPs in the leather products after the optimization of the SPE conditions. It was found that the interferences from the leather products were thor- oughly separated from the analyte of the SCCPs on a home-made solid phase extraction (SPE) column filled with silica packing while eluted with a mixed solvent of n-hexane-methylene chloride (2:1, v/v). With this method, the recoveries for the SCCPs spiked in the real leather samples varied from 90.47% to 99.00% with the relative standard deviations (RSDs) less than 6.7%, and the limits of detection (LODs) were between 0.069 and 0.110 mg/kg. This method is suitable for qualitative and quantitative analysis of SCCPs in the leather products.

  16. Complete Detoxification of Short Chain Chlorinated Aliphatic Compounds: Isolation of Halorespiring Organisms and Biochemical Studies of the Dehalogenating Enzyme Systems - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Tiedje, J.M.

    1999-10-01

    Work focused on the isolation and characterization of halorespiring populations, and the initial investigation of the dechlorinating enzyme systems. In addition, tools to evaluate the presence/activity to halorespiring populations in the environment were developed. The tools developed in this work (measurements of hydrogen consumption thresholds, molecular probes) are relevant for regulatory agencies in order to facilitate decisions on which bioremediation technology (biostimulation or bioaugmentation) is most promising at a particular site. In addition, a better understanding of the physiology of the halorespiring organisms as well as the biochemistry of the dehalogenating enzyme systems enhances our knowledge of how these organisms can successfully be employed in the bioremediation of contaminated sites.

  17. Medium-Chain Chlorinated Paraffins (CPs) Dominate in Australian Sewage Sludge.

    Science.gov (United States)

    Brandsma, Sicco H; van Mourik, Louise; O'Brien, Jake W; Eaglesham, Geoff; Leonards, Pim E G; de Boer, Jacob; Gallen, Christie; Mueller, Jochen; Gaus, Caroline; Bogdal, Christian

    2017-03-02

    To simultaneously quantify and profile the complex mixture of short-, median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian sewage sludge, we applied and further validated a recently developed novel instrumental technique, using quadrupole time-of-flight high resolution mass spectrometry running in the negative atmospheric pressure chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical column the cleaned extracts were directly injected into the qTOF-HRMS followed by quantification of the CPs by a mathematical algorithm. The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast and promising technique for routinely measuring SCCPs, MCCPs, and LCCPs in sewage sludge. Australian sewage sludge was dominated by MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight (dw). Lower SCCPs concentrations (<57-1421 ng/g dw) were detected in the Australian sewage sludge, which were comparable with the LCCPs concentrations (116-960 ng/g dw). This is the first time that CPs were reported in Australian sewage sludge. The results of this study gives a first impression on the distribution of the SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs).

  18. Occurrence of polychlorinated naphthalenes, polychlorinated biphenyls and short-chain chlorinated paraffins in marine sediments from Barcelona (Spain).

    Science.gov (United States)

    Castells, P; Parera, J; Santos, F J; Galceran, M T

    2008-02-01

    Polychlorinated naphthalenes (PCNs), short-chain chlorinated paraffins (SCCPs) and polychlorinated biphenyls (PCBs) were analysed in marine sediment samples collected from the coastal area of Barcelona (Spain) and near of a submarine emissary coming from a waste water treatment plant located at the mouth of the Besòs River (Barcelona). An integrated sample treatment based on Soxhlet extraction followed by a simple clean-up with Florisil and graphitized carbon cartridge was employed. Gas chromatography coupled to ion-trap tandem mass spectrometry (GC-MS/MS) and gas chromatography-mass spectrometry in electron capture negative ionization mode, were used for PCN and SCCP determinations, respectively, while for PCB analysis gas chromatography with electron capture detection (GC-ECD) was used. The method developed provided low limits of detection (0.001-0.003 ng g(-1) dry weight (dw) for PCNs, 1.8 ng g(-1) for SCCPs and 0.006-0.014 ng g(-1)dw for PCBs) and good run-to-run precisions (lower than RSD 8%) for the analysis of sediment samples. Concentration levels ranging from 0.17 to 3.27 ng g(-1)dw for PCNs, between 0.21 and 1.17 microg g(-1)dw for SCCPs, and from 2.33 to 44.00 ng g(-1) (dw) for PCBs, were found in the coastal sediments, while for samples collected near to the submarine emissary higher levels (from 2.02 to 6.56 ng g(-1)dw for PCNs, between 1.25 and 2.09 microg g(-1)dw for SCCPs and from 22.34 to 37.74 ng g(-1)dw for PCBs) were obtained. The results obtained provide new data about the occurrence of PCN and SCCP in the coastal area of Barcelona.

  19. Assessment of the endocrine-disrupting effects of short-chain chlorinated paraffins in in vitro models.

    Science.gov (United States)

    Zhang, Quan; Wang, Jinghua; Zhu, Jianqiang; Liu, Jing; Zhang, Jianyun; Zhao, Meirong

    2016-09-01

    Short-chain chlorinated paraffins (SCCPs), which are candidate persistent organic pollutants (POPs) according to the Stockholm Convention, are of great concern because of their persistent bioaccumulation, long-range transport and potential adverse health effects. However, data on the endocrine-disrupting effects of SCCPs remain scarce. In this study, we first adopted two in vitro models (reporter gene assays and H295R cell line) to investigate the endocrine-disrupting effects of three SCCPs (C10-40.40%, C10-66.10% and C11-43.20%) via receptor mediated and non-receptor mediated pathway. The dual-luciferase reporter gene assay revealed that all test chemicals significantly induced estrogenic effects, which were mediated by estrogen receptor α (ERα), in the following order: C11-43.20%>C10-66.10%>C10-40.40%. Notably, C10-40.40% and C10-66.10% also demonstrated remarkable anti-estrogenic activities. Only C11-43.20% showed glucocorticoid receptor-mediated (GR) antagonistic activity, with a RIC20 value of 2.6×10(-8)mol/L. None of the SCCPs showed any agonistic or antagonistic activities against thyroid receptor β (TRβ). Meanwhile, all test SCCPs stimulated the secretion of 17β-estradiol (E2). Both C10-66.10% and C11-43.20% increased the production of cortisol at a high level in H295R cell lines. In order to explore the possible mechanism underlying the endocrine-disrupting effects of SCCPs through the non-receptor pathway, the mRNA levels of 9 steroidogenic genes were measured by real-time polymerase chain reaction (RT-PCR). StAR, 17βHSD, CYP11A1, CYP11B1, CYP19 and CYP21 were upregulated in a concentration-dependent manner by all chemicals. The data provided here emphasized that comprehensive assessments of the health and ecological risks of emerging contaminants, such as SCCPs, are of great concern and should be investigated further.

  20. Aliphatic side chains of proteins as potential geomarkers of NOM liberated from the melting permafrost and discharged to the Arctic Ocean by the Kolyma River run off

    Science.gov (United States)

    Dubinenkov, I. V.; Perminova, I.; Kononikhin, A.; Nikolaev, E.; Hertkorn, N.; Bulygina, E. B.; Holmes, R. M.

    2011-12-01

    The Arctic ecosystem is highly sensitive to climate change. Global warming might have considerable effects on regional carbon cycling due to permafrost melting. Permafrost in the Arctic region represents an extremely large organic carbon reservoir mostly stored in the permafrost. Mobilization of just a small portion of carbon stored in Arctic soils will have considerable impacts on the flux of organic carbon from land to the Arctic Ocean, which can affect the Arctic environment. The Kolyma River watershed is one of the Arctic Ocean's largest. It is dominated by continuous permafrost which is underlain with rich organic soils susceptible to increased fluvial transport. The goal of the work was to analyze the structure of isolated natural organic matter from different fresh water environments of the Kolyma river basin. NOM was isolated from the Kolyma River main stream, its tributaries, a thermokarst lake, a floodplain stream and the permafrost. Solid phase extraction technique was used with Bond Elute PPL cartridges. Nuclear magnetic resonance spectroscopy (NMR) and Fourier Transform Ion Cyclotron Resonance Mass Spectroscopy (FTICRMS) was used for structural studies because of unsurpassed molecular level structural information provided by these high resolution magnetic resonance techniques. The NOM samples from the Kolyma River showed high contents of non-substituted aliphatic structures with a low content of aromatics and carbohydrates. Aliphatic nature may indicate a microbial source of NOM in the form of degraded terpenoids and hopanols. It was shown that almost all NOM samples from the rivers had similar molecular composition enriched with aliphatic units. The samples from permafrost mud streams were significantly different and contained sharp peptide signatures. In general, permafrost NOM contained much less degraded peptide residuest as compared to riverine samples. Identification of these residues showed the presence of branched amino acids (valine, alanine

  1. [Analysis of short-chain chlorinated paraffins in sediment samples from the mouth of the Daliao River by HRGC/ECNI-LRMS].

    Science.gov (United States)

    Gao, Yuan; Wang, Cheng; Zhang, Hai-jun; Zou, Li-li; Tian, Yu-zeng; Chen, Ji-ping

    2010-08-01

    An analytical method for quantifying short-chain chlorinated paraffins (SCCPs) by high-resolution gas chromatography/electron capture negative ion low-resolution mass spectrometry (HRGC/ECNI-LRMS) was presented. The cleanup procedure with an acid silica gel column and activated neutral alumina column was optimized to remove the interferences. As illustration of the application of the method to environmental samples, it is found that lower chlorinated C10 and C11 compounds were the main SCCPs compounds in six sediment samples from the mouth of the Daliao River. The concentrations of SCCPs in sediments were determined to be in the range of 64.9-407.0 ng/g and showed a decreasing tendency from the shore to the remote location.

  2. 短链氯化石蜡的研究进展%Research progress of short chain chlorinated paraffins

    Institute of Scientific and Technical Information of China (English)

    朱志保; 周琴; 赵远

    2015-01-01

    短链氯化石蜡(SCCPs)是一类碳原子数为10~13的正构烷烃氯化衍生而成的复杂混合物,具有环境持久性、生物蓄积性和生物毒性,可长距离迁移。作为《关于持久性有机污染物的斯德哥尔摩公约》拟增列持久性有机污染物(persistent organic pollutants,POPs)之一,短链氯化石蜡的生物毒性、环境和人体健康风险及环境污染现状等的研究备受关注。本文概述了SCCPs的物理化学性质;详细比较了国内外对SCCPs的分析方法的优缺点,包括气相色谱-电子捕获检测器(GC-ECD)、气相色谱-电子轰击串联质谱(GC-EI/MS)、气相色谱-低分辨电子捕获负化学离子源质谱(GC-ECNI-LRMS)等;重点综述了SCCPs在全球环境介质(大气、土壤、底泥、水)及生物体中的污染现状;总结了SCCPs现有的污染控制技术,包括生物降解、光降解、吸附等;同时,针对目前存在的问题,对SCCPs今后的研究方向进行了展望,以期为该领域相关的研究工作提供参考。%Short chain chlorinated paraffins (SCCPs),which are chlorinated derivatives of n-alkanes, are a group of complex mixtures that include 10—13 carbon atoms. They have some conmmon properties,such as environmental persistence,biotoxicity,bioaccumulation and long-distance transport. Having been considered as candidates to be added to the list on persistent organic pollutants (POPs) by the Stockholm Convention,SCCPs have been widely paid attention recently. In this paper,the physicochemical properties of SCCPs are described,and various analytical methods of SCCPs are compared,including gas chromatography with electron capture detector (GC-ECD),gas chromatography-electron impact ionization mass spectrometry (GC-EI/MS),and gas chromatography- electron capture negative chemical ion source low resolution mass spectrometry (GC-ECNI-LRMS). Meanwhile,the pollution occurrence of SCCPs in the global

  3. A Mechanism for the induction of renal tumours in male Fischer 344 rats by short-chain chlorinated paraffins.

    Science.gov (United States)

    Warnasuriya, Gayathri D; Elcombe, Barbara M; Foster, John R; Elcombe, Clifford R

    2010-03-01

    Short-chain chlorinated paraffins (SCCPs) cause kidney tumours in male rats, but not in female rats or mice of either sex. Male rat-specific tumours also occur in rats dosed with a range of compounds including 1,4- dichlorobenzene (DCB) and d-limonene (DL). These compounds bind to a male rat-specific hepatic protein, alpha-2-urinary globulin (α2u), and form degradationresistant complexes in the kidney. The resulting accumulation of α2u causes cell death and sustained regenerative cell proliferation, which in turn leads to the formation of renal tumours. To investigate whether the SCCP, Chlorowax 500C (C500C), causes tumours via the accumulation of α2u male rats were orally dosed with either C500C (625 mg/kg of body weight), DCB (300 mg/kg of body weight), or DL (150 mg/kg of body weight) for 28 consecutive days. An increase in renal α2u and cell proliferation was observed in DCB- and DL-treated rats but not in C500C-treated rats. C500C caused peroxisome proliferation and a down-regulation of α2u synthesis in male rat liver. This down-regulation occurred at the transcriptional level. Since less α2u was produced in C500C-treated rats, there was less available for accumulation in the kidney hence a typical α2u nephropathy did not appear. However, the administration of a radiolabelled SCCP, [14C]polychlorotridecane (PCTD), to male rats demonstrated its binding to renal α2u. Thus, it is possible that SCCPs bind to α2u and cause a slow accumulation of the protein in the kidney followed by delayed onset of α2u nephropathy. As a consequence of these findings in the current experiments, while evidence exists implicating α2u-globulin in the molecular mechanism of action of the C500C, the classic profile of a α2u-globulin nephropathy seen with other chemicals such as DCB and DL was not reproduced during this experimental protocol.

  4. Separation and screening of short-chain chlorinated paraffins in environmental samples using comprehensive two-dimensional gas chromatography with micro electron capture detection.

    Science.gov (United States)

    Xia, Dan; Gao, Lirong; Zhu, Shuai; Zheng, Minghui

    2014-11-01

    Short-chain chlorinated paraffins (SCCPs) are highly complex technical mixtures with thousands of isomers and numerous homologs. They are classified as priority candidate persistent organic pollutants under the Stockholm Convention for their persistence, bioaccumulation, and toxicity. Analyzing SCCPs is challenging because of the complexity of the mixtures. Chromatograms of SCCPs acquired using one-dimensional (1D) gas chromatography (GC) contain a large characteristic "peak" with a broad and unresolved profile. Comprehensive two-dimensional GC (GC×GC) shows excellent potential for separating complex mixtures. In this study, GC×GC coupled with micro electron capture detection (μECD) was used to separate and screen SCCPs. The chromatographic parameters, including the GC column types, oven temperature program, and modulation period, were systematically optimized. The SCCP congeners were separated into groups using a DM-1 column connected to a BPX-50 column. The SCCP congeners in technical mixtures were separated according to the number of chlorine substituents for a given carbon chain length and according to the number of carbon atoms plus chlorine atoms for different carbon chain lengths. A fish tissue sample was analyzed to illustrate the feasibility of the GC×GC-μECD method in analyzing biological samples. Over 1,500 compounds were identified in the fish extract, significantly more than were identified using 1D GC. The detection limits for five selected SCCP congeners were between 1 and 5 pg/L using the GC×GC method, and these were significantly lower than those achieved using 1D GC. This method is a good choice for analysis of SCCPs in environmental samples, exhibiting good separation and good sensitivity.

  5. Comparison of quantitative analytical methods of short chain chlorinated paraffins in chlorinated paraffin mixtures%混合氯化石蜡中短链氯化石蜡定量分析方法的比较

    Institute of Scientific and Technical Information of China (English)

    幸苑娜; 冯岸红; 叶淋泉; 林志惠; 陈茜; 陈泽勇

    2016-01-01

    Total response factor correction method and multiple linear regression method were adopted to quantify the sum of short chain chlorinated paraffins( SCCPs)in chlorinated paraffin mixtures. Both methods were based on electron capture negative ionization mass spectrometry. The results showed that high SCCPs quantitative accuracies were obtained by the two methods both with eliminating the potential interferences of mediumchain chlorinated paraffins. However,both two methods were slightly dependent on the ranges of calibration solutions. Dilution of the sample solution was necessary when performing these two methods. Besides, multiple linear regression method was suitable for more wide-quantitative-range of SCCPs than total response factor correction method.%分别采用总体响应因子校正法和多元线性回归法对混合氯化石蜡中短链氯化石蜡进行定量分析,结果表明:两种方法均能较好地排除中链氯化石蜡的干扰,从而提高了短链氯化石蜡的定量准确性;但是两种方法均对标准曲线的浓度范围存在一定的依赖性,在使用这两种方法进行定量分析时,应将样品稀释到标准曲线适用的浓度范围。另外,相对于总体响应因子校正法,多元线性回归法定量范围更广。

  6. Occurrence and gas/particle partitioning of short- and medium-chain chlorinated paraffins in the atmosphere of Fildes Peninsula of Antarctica

    Science.gov (United States)

    Ma, Xindong; Zhang, Haijun; Zhou, Hongqiang; Na, Guangshui; Wang, Zhen; Chen, Chen; Chen, Jingwen; Chen, Jiping

    2014-06-01

    Chlorinated paraffins (CPs) were measured in air samples at a remote air monitoring site established in Georgia King Island, Fildes Peninsula of Antarctica (Great Wall Station, China) to study the long-range atmospheric transport of these anthropogenic pollutants to the Antarctic. Gas- and particle-phase CPs were collected using polyurethane foam plugs (PUF) and glass fiber filters (GFF) respectively during summertime of 2012. The total atmospheric levels of SCCPs and MCCPs ranged from 9.6 to 20.8 pg m-3 (average: 14.9 pg m-3) and 3.7-5.2 pg m-3 (average: 4.5 pg m-3), respectively. C10 and C11 carbon chain homologues with Cl5 and Cl6 chlorine atoms predominated in SCCP formula groups both in gas- and particle-phase. Significant linear correlation was found between gas/particle partition coefficients (KP) and sub-cooled liquid vapor pressures (pL°) (R2 = 0.437, p < 0.01), as well as KP and octanol-air partition coefficients (KOA) (R2 = 0.442, p < 0.01). Absolute slope values of two regression models (0.31 and 0.39) were less than 0.6 indicating that the way of absorption into organic matter of aerosol played a more important role on atmospheric partitioning and transferring of CPs in remote Antarctic area. Both the Junge-Pankow model and the KOA-based model tended to underestimate the sorption of lower chlorinated CPs and overestimate the sorption of highly chlorinated CPs.

  7. Spatial and temporal trends of short- and medium-chain chlorinated paraffins in sediments off the urbanized coastal zones in China and Japan: A comparison study.

    Science.gov (United States)

    Zeng, Lixi; Lam, James C W; Horii, Yuichi; Li, Xiaolin; Chen, Weifang; Qiu, Jian-Wen; Leung, Kenneth M Y; Yamazaki, Eriko; Yamashita, Nobuyoshi; Lam, Paul K S

    2017-05-01

    To examine the impacts of urbanization and industrialization on the coastal environment, and assess the effectiveness of control measures on the contamination by chlorinated paraffins (CPs) in East Asia, surface and core sediments were sampled from the urbanized coastal zones in China and Japan (i.e., Pearl River Delta (PRD), Hong Kong waters and Tokyo Bay) and analyzed for short-chain (SCCPs) and medium-chain CPs (MCCPs). Much higher concentrations of CPs were found in the industrialized PRD than in adjacent Hong Kong waters. Significant correlation between CP concentration and population density in the coastal district of Hong Kong was observed (r(2) = 0.72 for SCCPs and 0.55 for MCCPs, p harbor with Tokyo Bay shows the striking difference in historical deposition of CPs under different regulatory situations in China and Japan. For the first time, the declining CP concentrations in Tokyo Bay, Japan, attest to the effectiveness of emissions controls.

  8. Occurrence, bioaccumulation and long-range transport of short-chain chlorinated paraffins on the Fildes Peninsula at King George Island, Antarctica.

    Science.gov (United States)

    Li, Huijuan; Fu, Jianjie; Zhang, Aiqian; Zhang, Qinghua; Wang, Yawei

    2016-09-01

    As a candidate persistent organic pollutant of the Stockholm Convention, short-chain chlorinated paraffins (SCCPs) have recently received particular attention. In this study, we investigated, for the first time, the concentrations of SCCPs in biota samples collected from the Fildes Peninsula at King George Island and Ardley Island, Antarctica. The concentrations of SCCPs ranged from 3.5 to 256.6ng/g (dry weight, dw), with a mean of 76.6±61.8ng/g dw, which was lower than those detected in mid- and low-latitude regions. The long-range transport behaviour of SCCPs was confirmed by both the detection of SCCPs in Antarctic remote areas and their special congener profiles. Short carbon chain (C10) congeners predominated in the Antarctic samples, which accounted for 56.1% of the total SCCP contamination. Such enrichment of C10 congeners indicated the high potential for the long-range transport of shorter chain congeners. In addition, SCCPs tended to be enriched in the species with high lipid contents. The biomagnification potential of SCCPs was found between Archeogastropoda (Agas) and Neogastropoda (Ngas), and the biomagnification factors of shorter chain congeners of SCCPs were higher than that of the longer chain ones. Considering that the endemic species in polar regions may be sensitive and vulnerable to the adverse effects of environmental contaminants, more attention should be paid on the bioaccumulation and toxicological risks of SCCPs in polar environments.

  9. Changes in thyroid parameters of hatchling American kestrels (Falco sparverius) following embryonic exposure to technical short chain chlorinated paraffins (SCCPs; C10-13, 55.5% CL)

    Science.gov (United States)

    Fernie, Kimberly J; Henry, Paula F.; Letcher, Robert J; Palace, Vince; Peters, Lisa; Rattner, Barnett A.; Sverko, Edward; Karouna, Natalie

    2015-01-01

    Chlorinated paraffins (CPs) are complex mixtures of polychlorinated n-alkanes categorized according to their carbon chain length: short chain (SCCPs, C10 – C13), medium (C14 - C17), and long chain (C>17), chlorinated paraffins. SCCPs are primarily used in metalworking applications, as flame retardants, and in paints, adhesives, sealants, textiles, plastics and rubber (UNEP 2012). In 2012, the United Nations Environment Program (UNEP 2012) reported in the Revised Draft Risk Profile for SCCPs, that CPs were produced in the United States, the European Union (EU), Slovakia, Brazil, India, Japan and China. While annual global consumption of SCCPs is large (>25 tonnes/year), it has sharply declined over the past 20 years. SCCPs are released through wastewater, landfills, and air emissions (UNEP 2012). Concentrations of SCCPs have been reported in fish and marine mammals in North and South America, Europe, Japan, Greenland and the Arctic (UNEP 2012 and references therein). Characterization of SCCP concentrations and exposure in terrestrial wildlife is limited. In 2010, SCCP concentrations were reported in the eggs of yellow-legged gulls (Larus michahellis) (4536 ± 40 pg/g wet weight (ww)) and Audouin’s gulls (Larus audouinii) (6364 ± 20 pg/g ww) in Spain (Morales et al. 2012), and little auks (Alle alle) (5 - 88 ng/g ww) and kittiwakes (Rissa tridactyla) (5 - 44 ng/g ww) in the European Arctic (Reth et al. 2006). In Sweden, muscle of ospreys contained CPs of unspecified chain length (Jansson et al. 1993). Although the toxicity of SCCPs has been demonstrated in aquatic invertebrates, fish, frogs, and laboratory rats, there are limited avian studies and these reported no effects of SCCPs on egg parameters of domestic hens (Gallus gallus domesticus) and ducks (Anas platyrhynchos) (UNEP 2012). Despite reported accumulation of SCCPs in wild birds, to our knowledge, exposure-related toxicities and effects with respect to avian wildlife remain unknown.

  10. 扩链剂对脂肪族水性聚氨酯性能的影响%Effect of Chain Extender on Properties of Aliphatic Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    张红武; 倪忠斌; 陈明清; 刘士荣

    2012-01-01

    A series of waterborne polyurethane dispersions were synthesized from PPG. IPDI. DMPA and EDA by prepolymer dispersion method. The effects of DMPA content and the method of chain extension with EDA on the emulsion stability and particle size, the mechanical properties and the ratio of absorbent water for waterborne polyurethane film were studied. The results show that, good performance of polyurethane emulsion was gained under the conditions of the content of DMPA = 6%, and the method of chain extension of EDA soluble in water.%以异佛尔酮二异氰酸酯(IPDI)和聚酸二醇(PPG:Mn=1000)为原料进行预聚反应,二羟甲基丙酸(DMPA)为亲水扩链剂,按不同配比合成了水性聚氨酯,并就DMPA用量、乙二胺(EDA)扩链方式对水性聚氨酯乳液的稳定性、粒径、及其材料的力学性能、吸水率等的影响进行了研究。结果表明:DMPA用量6%左右,EDA溶于水中进行边扩链、边乳化的方法制得了综合性能较好的水性聚氨酯。

  11. Congener-specific distribution and bioaccumulation of short-chain chlorinated paraffins in sediments and bivalves of the Bohai Sea, China.

    Science.gov (United States)

    Ma, Xindong; Chen, Chen; Zhang, Haijun; Gao, Yuan; Wang, Zhen; Yao, Ziwei; Chen, Jiping; Chen, Jingwen

    2014-02-15

    Short-chain chlorinated paraffins (SCCPs) are a new type of persistent organic pollutants that are of great environmental concern because of their wide distribution. In this study, surface sediments and bivalve samples were collected from the coastal area of the Bohai Sea in China. Total SCCP (ΣSCCP) concentrations in surface sediments and bivalves ranged from 97.4 ng g(-1) dry weight (dw) to 1756.7 ng g(-1) dw and 476.4-3269.5 ng g(-1) dw, respectively. C10-CPs and C11-CPs were the predominant homologue groups in all sediments and bivalves. Specific congener composition analysis and correspondence analysis indicated that the local SCCP source mainly came from CP-42 and CP-52 products, and riverine input had an important function. The biota-sediment accumulation factors of ΣSCCPs for bivalves ranged from 1.08 to 1.61, and a significant correlation indicated that the SCCP congener with higher chlorination degree was more likely to be accumulated in bivalves.

  12. Screening of atmospheric short- and medium-chain chlorinated paraffins in India and Pakistan using polyurethane foam based passive air sampler.

    Science.gov (United States)

    Chaemfa, Chakra; Xu, Yue; Li, Jun; Chakraborty, Paromita; Hussain Syed, Jabir; Naseem Malik, Riffat; Wang, Yan; Tian, Chongguo; Zhang, Gan; Jones, Kevin C

    2014-05-06

    Production and use of chlorinated paraffins (CPs) have been increasing in India. Distribution of CPs in the area and vicinity have become a great concern due to their persistency and toxicity. Polyurethane foam based passive air samplers (PUF-PAS) was deployed in order to screen the presence of short- and medium- chain chlorinated paraffins (SCCPs and MCCPs) in the outdoor atmosphere at many sites in India (in winter 2006) and Pakistan (in winter 2011). Concentrations of SCCPs and MCCPs ranged from not detected (ND) to 47.4 and 0 to 38.2 ng m(-3) with means of 8.11 and 4.83 ng m(-3), respectively. Indian concentrations showed higher average levels of both SCCPs and MCCPs India (10.2 ng m(-3) and 3.62 ng m(-3)than the samples from Pakistan (5.13 ng m(-3) and 4.21 ng m(-3)). Relative abundance patterns of carbon number are C10 > C11 > C12 ∼ C13 for SCCPs and C14 > C15 > C16 C17 for MCCP with similarity to the profiles of samples from China, the biggest CPs producer in the world. Principal Component Analysis suggested that detected SCCPs and MCCPs in this study originated from the same emission source.

  13. Formation of disinfection byproducts upon chlorine dioxide preoxidation followed by chlorination or chloramination of natural organic matter.

    Science.gov (United States)

    Yang, Xin; Guo, Wanhong; Lee, Wontae

    2013-06-01

    Chlorine dioxide (ClO2) is often used as an oxidant to remove taste, odor and color during water treatment. Due to the concerns of the chlorite formation, chlorination or chloramination is often applied after ClO2 preoxidation. We investigated the formation of regulated and emerging disinfection byproducts (DBPs) in sequential ClO2-chlorination and ClO2-chloramination processes. To clarify the relationship between the formation of DBPs and the characteristics of natural organic matter (NOM), changes in the properties of NOM before and after ClO2 oxidation were characterized by fluorescence, Fourier transform infrared spectroscopy (FTIR), and size and resin fractionation techniques. ClO2 preoxidation destroyed the aromatic and conjugated structures of NOM and transformed large aromatic and long aliphatic chain organics to small and hydrophilic organics. Treatment with ClO2 alone did not produce significant amount of trihalomethanes (THMs) and haloacetic acids (HAAs), but produced chlorite. ClO2 preoxidation reduced THMs, HAAs, haloacetonitriles (HANs) and chloral hydrate (CH) during subsequent chlorination, but no reduction of THMs was observed during chloramination. Increasing ClO2 doses enhanced the reduction of most DBPs except halonitromethanes (HNMs) and haloketones (HKs). The presence of bromide increased the formation of total amount of DBPs and also shifted DBPs to more brominated ones. Bromine incorporation was higher in ClO2 treated samples. The results indicated that ClO2 preoxidation prior to chlorination is applicable for control of THM, HAA and HAN in both pristine and polluted waters, but chlorite formation is a concern and HNMs and HKs are not effectively controlled by ClO2 preoxidation.

  14. Distribution and congener profiles of short-chain chlorinated paraffins in indoor/outdoor glass window surface films and their film-air partitioning in Beijing, China.

    Science.gov (United States)

    Gao, Wei; Wu, Jing; Wang, Yawei; Jiang, Guibin

    2016-02-01

    Short-chain chlorinated paraffins (SCCPs) are a group of n-alkanes with carbon chain length of 10-13. In this work, paired indoor/outdoor samples of organic films on window glass surfaces from urban buildings in Beijing, China, were collected to measure the concentrations and congener distributions of SCCPs. The total SCCP levels ranged from 337 ng/m(2) to 114 μg/m(2), with total organic carbon (TOC) normalized concentrations of 365 μg/m(2)-365 mg/m(2). Overall, the concentrations of SCCPs on the interior films were higher than the concentrations on the exterior films, suggesting an important indoor environmental exposure of SCCPs to the general public. A significant linear relationship was found between the SCCP concentrations and TOC, with a correlation coefficient of R = 0.34 (p < 0.01). A film-air partitioning model suggests that the indoor gas-phase SCCPs are related to their corresponding window film levels.

  15. Biofiltration of gasoline and diesel aliphatic hydrocarbons.

    Science.gov (United States)

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

    2015-02-01

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

  16. Short-chain chlorinated paraffins in marine organisms from the Pearl River Estuary in South China: Residue levels and interspecies differences.

    Science.gov (United States)

    Sun, Runxia; Luo, Xiaojun; Tang, Bin; Li, Zongrui; Huang, Liqian; Wang, Tao; Mai, Bixian

    2016-05-15

    There is limited information available on the bioaccumulation of short-chain chlorinated paraffins (SCCPs), a complicated group of persistent organic pollutants (POPs) candidates listed in the Stockholm Convention, in estuarine ecosystem. This study analyzed SCCPs in marine organisms (five fish and six invertebrates) from the Pearl River Estuary in South China. The concentrations of total SCCPs ranged from 210 to 21,000 ng · g(-1) lipid weight, with relatively higher levels in benthic invertebrates (shrimp, crabs and bivalves) than in non-benthic species (pelagic and mesopelagic fish and squid). SCCPs were biomagnified from prey fish (tapertail anchovy, Coilia mystus) to predator fish (Bombay duck, Harpadon nehereus), and the biomagnification factors (BMFs) of SCCP congeners ranged from 1.1 (C10H16Cl6) to 3.4 (C13H18Cl10). Species-specific homologue group patterns were also observed, with significantly lower proportions of C10 congeners in the shrimp, bivalves and Bombay duck than in the other species.

  17. Review on Short-chain Chlorinated Paraffins Pollution in Water%水体中短链氯化石蜡污染研究进展

    Institute of Scientific and Technical Information of China (English)

    周浩郎; 邢永泽; 阎冰

    2016-01-01

    Short-chain chlorinated paraffins (SCCPs),as a candidate of persistent organic pol-lutants in “Stockholm Convention”,have potential hazard to ecological environment and peo-ple health,which becomes a new hotspot in field of environmental science worldwide.The water is an important destination of SCCPs.The distribution of SCCPs in different environ-mental media and the potential threaten of SCCPs to aquatic animals were critically reviewed in this paper.Meanwhile,the research progress and trend of SCCPs were also reviewed.%短链氯化石蜡(SCCPs)拟列入“斯德哥尔摩公约”禁止使用的一类持久性有机污染物,对生态环境和人体健康具有极大的潜在危害,已成为国际环境科学领域的一个研究热点。水体是 SCCPs 重要的“汇”,本文着重综述了水生态系统中沉积物、水、生物体等不同环境介质中 SCCPs 的含量分布及对水生生物的危害,并对SCCPs 的研究重点和前景进行展望。

  18. Short- and medium-chain chlorinated paraffins in air and soil of subtropical terrestrial environment in the pearl river delta, South China: distribution, composition, atmospheric deposition fluxes, and environmental fate.

    Science.gov (United States)

    Wang, Yan; Li, Jun; Cheng, Zhineng; Li, Qilu; Pan, Xiaohui; Zhang, Ruijie; Liu, Di; Luo, Chunling; Liu, Xiang; Katsoyiannis, Athanasios; Zhang, Gan

    2013-03-19

    Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 μg/sampler (17.69 ng/m(3)) and 4.1 μg/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 μg/(m(2)d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C(10-11) C(l6-7) and C(14) C(l6-7), C(10-12) C(l6-7) and C(14) C(l6-8), and C(11-12) C(l6-8) and C(14) C(l7-8) dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.

  19. Kinetics of Bacterial Growth on Chlorinated Aliphatic Compounds

    NARCIS (Netherlands)

    van den Wijngaard, Abraham; Wind, Richele; Janssen, Dick B.

    1993-01-01

    With the pure bacterial cultures Ancylobacter aquaticus AD20 and AD25, Xanthobacter autotrophicus GJ10, and Pseudomonas sp. strain AD1, Monod kinetics was observed during growth in chemostat cultures on 1,2-dichloroethane (AD20, AD25, and GJ10), 2-chloroethanol (AD20 and GJIO), and 1,3-dichloro-2-pr

  20. 皮革中短链氯化石蜡的GC—ECD测定方法探讨%Determination of Short Chain Chlorinated Paraffins in Leather by Gas Chromatography Combined Electron Capture Detector

    Institute of Scientific and Technical Information of China (English)

    马贺伟

    2012-01-01

    Analysis of short - chain chlorinated paraffins (SCCPs) in leather was studied using gas chromatography combined electron capture detector (GC -ECD). The results show the wide co -eluting chromatogram of SCCPs, and the response factors are dependent on the degree of chlorination. Significant interference problems from medium - chain chlorinated paraffins ( MC- CPs) are expected due to the difficult chromatographic separation. GC - ECD could not provide satisfactory results for scanning SCCPs in leather because of the low selectivity and the complex matrix influences.%采用气相色谱-电子捕获检测器(GC—ECD)对皮革中的短链氯化石蜡(SCCPs)进行测定。结果表明:SCCPs的GC—ECD共流出色谱峰保留时间跨度大,仪器响应值表现出对氯含量的依赖;中链氯化石蜡(MCCPs)的存在对SCCPs的分析过程干扰严重;实际皮革基质非常复杂,导致样品中SCCPs的定性困难。

  1. Biodegradation of aliphatic and aromatic polycarbonates.

    Science.gov (United States)

    Artham, Trishul; Doble, Mukesh

    2008-01-01

    Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.

  2. Parameters optimization using experimental design for headspace solid phase micro-extraction analysis of short-chain chlorinated paraffins in waters under the European water framework directive.

    Science.gov (United States)

    Gandolfi, F; Malleret, L; Sergent, M; Doumenq, P

    2015-08-07

    The water framework directives (WFD 2000/60/EC and 2013/39/EU) force European countries to monitor the quality of their aquatic environment. Among the priority hazardous substances targeted by the WFD, short chain chlorinated paraffins C10-C13 (SCCPs), still represent an analytical challenge, because few laboratories are nowadays able to analyze them. Moreover, an annual average quality standards as low as 0.4μgL(-1) was set for SCCPs in surface water. Therefore, to test for compliance, the implementation of sensitive and reliable analysis method of SCCPs in water are required. The aim of this work was to address this issue by evaluating automated solid phase micro-extraction (SPME) combined on line with gas chromatography-electron capture negative ionization mass spectrometry (GC/ECNI-MS). Fiber polymer, extraction mode, ionic strength, extraction temperature and time were the most significant thermodynamic and kinetic parameters studied. To determine the suitable factors working ranges, the study of the extraction conditions was first carried out by using a classical one factor-at-a-time approach. Then a mixed level factorial 3×2(3) design was performed, in order to give rise to the most influent parameters and to estimate potential interactions effects between them. The most influent factors, i.e. extraction temperature and duration, were optimized by using a second experimental design, in order to maximize the chromatographic response. At the close of the study, a method involving headspace SPME (HS-SPME) coupled to GC/ECNI-MS is proposed. The optimum extraction conditions were sample temperature 90°C, extraction time 80min, with the PDMS 100μm fiber and desorption at 250°C during 2min. Linear response from 0.2ngmL(-1) to 10ngmL(-1) with r(2)=0.99 and limits of detection and quantification, respectively of 4pgmL(-1) and 120pgmL(-1) in MilliQ water, were achieved. The method proved to be applicable in different types of waters and show key advantages, such

  3. Chemiluminescence of the peroxomonosulphate-cobalt(II)-aliphatic monocarboxylic acids system.

    Science.gov (United States)

    Wang, Min; Zhao, Lixia; Lin, Jin-Ming

    2007-01-01

    A weak chemiluminescence (CL) emission was observed due to the production of singlet oxygen ((1)O(2)) during the decomposition of peroxomonosulphate (HSO(5)(-)) catalysed by cobalt(II). Low molecular mass aliphatic monocarboxylic acids, such as formic, acetic, propionic, butyric and valeric acids, influenced the CL emission, and the reaction of aliphatic monocarboxylic acids with HSO(5)(-)/Co(2+) solution was further investigated using a flow injection analysis (FIA) CL method. The results indicated that the CL intensities of aliphatic monocarboxylic acids were improved with increase in the carbon chain length in the potassium peroxomonosulphate-cobalt(II) sulphate system. Generation of singlet oxygen was confirmed by the fact that the CL emission of aliphatic monocarboxylic acids with the HSO(5)(-)/Co(2+) solution was quenched by NaN(3), and from the CL spectrum of the reaction system. Additionally, a possible mechanism of aliphatic monocarboxylic acids CL emission enhancement was proposed.

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

    Directory of Open Access Journals (Sweden)

    Jules Beekwilder

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

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

    Science.gov (United States)

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

    2008-04-30

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

  6. Aliphatic hydrocarbons of the fungi.

    Science.gov (United States)

    Weete, J. D.

    1972-01-01

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

  7. Transformation of iopamidol during chlorination.

    Science.gov (United States)

    Wendel, Friedrich M; Lütke Eversloh, Christian; Machek, Edward J; Duirk, Stephen E; Plewa, Michael J; Richardson, Susan D; Ternes, Thomas A

    2014-11-01

    The transformation of the iodinated X-ray contrast media (ICM) iopamidol, iopromide, iohexol, iomeprol, and diatrizoate was examined in purified water over the pH range from 6.5 to 8.5 in the presence of sodium hypochlorite, monochloramine, and chlorine dioxide. In the presence of aqueous chlorine, only iopamidol was transformed. All other ICM did not show significant reactivity, regardless of the oxidant used. Chlorination of iopamidol followed a second order reaction, with an observed rate constant of up to 0.87 M(-1) s(-1) (±0.021 M(-1) s(-1)) at pH 8.5. The hypochlorite anion was identified to be the reactive chlorine species. Iodine was released during the transformation of iopamidol, and was mainly oxidized to iodate. Only a small percentage (less than 2% after 24 h) was transformed to known organic iodinated disinfection byproducts (DBPs) of low molecular weight. Some of the iodine was still present in high-molecular weight DBPs. The chemical structures of these DBPs were elucidated via MSn fragmentation and NMR. Side chain cleavage was observed as well as the exchange of iodine by chlorine. An overall transformation pathway was proposed for the degradation of iopamidol. CHO cell chronic cytotoxicity tests indicate that chlorination of iopamidol generates a toxic mixture of high molecular weight DBPs (LC50 332 ng/μL).

  8. [Determination of short-chain chlorinated paraffins in ambient air using high-volume sampling combined with high resolutimi gas chromatography-electron capture negative ion-low resolution mass spectrometry].

    Science.gov (United States)

    Shi, Loimeng; Gao, Yuan; Hou, Xiaohong; Zhang, Haijun; Zhang, Yichi; Chen, Jiping

    2016-02-01

    An analytical method for quantifying short-chain chlorinated paraffins (SCCPs) in ambient air using high-volume sampling combined with high resolution gas chromatography-electron capture negative ion-low resolution mass spectrometry ( HRGC-ECNI-LRMS) was developed. An acidified silica gel column and a basic alumina column were used to optimize the cleanup procedures. The results showed a good linearity (R2>0. 99) between the total response factors and the degree of chlorination of SCCPs in the content range of 58. 1%-63. 3%. The limits of detection (S/N ≥3) and the limits of quantification (S/N ≥ 10) were 4. 2 and 12 µg, respectively. The method detection limit (MDL) for SCCPs was 0. 34 ng/m3 (n = 7). The recoveries of SCCPs in air samples were in the range of 81. 9% to 94. 2%. It is demonstrated that the method is suitable for the quantitative analysis of SCCPs in air samples.

  9. Aqueous reactions of chlorine dioxide with hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Rav-Acha, C.; Choshen, E.

    1987-11-01

    In contrast to mechanisms proposed earlier in the literature, according to which chlorine dioxide (ClO/sub 2/) reacts with various hydrocarbons in aqueous media by abstracting allylic or benzylic hydrogens, it is shown that ClO/sub 2/ reacts with olefins through initial electron transfer. Hydrocarbons that can undergo facile oxidation, such as polycyclic aromatic hydrocarbons (PAH) and some olefins, react with ClO/sub 2/ quite rapidly, while saturated aliphatic hydrocarbons, some aromatic hydrocarbons, and olefins substituted with electron-withdrawing groups remain unreactive. This was substantiated by comparing the reactivities toward ClO/sub 2/ of a variety of hydrocarbons, including aliphatic and aromatic hydrocarbons, saturated and unsaturated acids, PAH, or cyclic and acyclic olefins. The results were supported by a detailed kinetic and product study of the reaction between ClO/sub 2/ and some model compounds.

  10. Short-chain chlorinated paraffins in soil, paddy seeds (Oryza sativa) and snails (Ampullariidae) in an e-waste dismantling area in China: Homologue group pattern, spatial distribution and risk assessment.

    Science.gov (United States)

    Yuan, Bo; Fu, Jianjie; Wang, Yawei; Jiang, Guibin

    2017-01-01

    Short-chain chlorinated paraffins (SCCPs) in multi-environmental matrices are studied in Taizhou, Zhejiang Province, China, which is a notorious e-waste dismantling area. The investigated matrices consist of paddy field soil, paddy seeds (Oryza sativa, separated into hulls and rice unpolished) and apple snails (Ampullariidae, inhabiting the paddy fields). The sampling area covered a 65-km radius around the contamination center. C10 and C11 are the two predominant homologue groups in the area, accounting for about 35.7% and 33.0% of total SCCPs, respectively. SCCPs in snails and hulls are generally higher than in soil samples (30.4-530 ng/g dw), and SCCPs in hulls are approximate five times higher than in corresponding rice samples (4.90-55.1 ng/g dw). Homologue pattern analysis indicates that paddy seeds (both hull and rice) tend to accumulate relatively high volatile SCCP homologues, especially the ones with shorter carbon chain length, while snails tend to accumulate relatively high lipophilic homologues, especially the ones with more substituted chlorines. SCCPs in both paddy seeds and snails are linearly related to those in the soil. The e-waste dismantling area, which covers a radius of approximate 20 km, shows higher pollution levels for SCCPs according to their spatial distribution in four matrices. The preliminary assessment indicates that SCCP levels in local soils pose no significant ecological risk for soil dwelling organisms, but higher risks from dietary exposure of SCCPs are suspected for people living in e-waste dismantling area.

  11. Oxidation of diclofenac by aqueous chlorine dioxide: identification of major disinfection byproducts and toxicity evaluation.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai

    2014-03-01

    Diclofenac (DCF), a synthetic non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the aquatic environment. In this work, the mechanism and toxicity of DCF degradation by ClO2 under simulated water disinfection conditions were investigated. Experimental results indicate that rapid and significant oxidation of DCF occurred within the first few minutes; however, its mineralization process was longer than its degradation process. UPLC-MS and (1)H NMR spectroscopy were performed to identify major disinfection byproducts that were generated in three tentative degradation routes. The two main routes were based on initial decarboxylation of DCF on the aliphatic chain and hydroxylation of the phenylacetic acid moiety at the C-4 position. Subsequently, the formed aldehyde intermediates were the starting point for further multistep degradation involving decarboxylation, hydroxylation, and oxidation reactions of CN bond cleavage. The third route was based on transient preservation of chlorinated derivatives resulting from electrophilic attack by chlorine on the aromatic ring, which similarly underwent CN bond cleavage. Microtox bioassay was employed to evaluate the cytotoxicity of solutions treated by ClO2. The formation of more toxic mid-byproducts during the ClO2 disinfection process poses a potential risk to consumers.

  12. Attachment of inorganic moieties onto aliphatic polyurethanes

    Directory of Open Access Journals (Sweden)

    Eliane Ayres

    2007-06-01

    Full Text Available Polyurethanes have been used in a series of applications due basically to their versatility in terms of controlling the behavior by altering basically the type of reagents used. However, for more specific and advanced applications, such as in membranes, biomaterials and sensors, well-organized and defined chemical functionalities are necessary. In this work, inorganic functionalities were incorporated into aliphatic polyurethanes (PU having different macromolecular architectures. Polyurethanes were synthesized using a polyether diol and dicyclohexylmethane 4,4' diisocyanate (H12-MDI. Polyurethanes having carboxylic acid groups were also produced by introducing 2,2- bis (hydroxymethyl propionic acid in the polymerization process. Inorganic functionalities were inserted into polyurethanes by reacting isocyanate end capped chains with aminopropyltriethoxysilane followed by tetraethoxysilane. PU having carboxylic acid groups yielded transparent samples after the incorporation of inorganic entities, as an evidence of smaller and better dispersed inorganic entities in the polymer network. FTIR and swelling measurements showed that polyurethanes having carboxylic acid groups had inorganic domains less packed, condensed and cross-linked when compared to polyurethanes with no carboxylic acid groups. Results also suggested that the progressive incorporation of inorganic moieties in both types of polyurethanes occurred in regions previously activated with inorganic functionalities, instead of by the creation of new domains. The temperatures of thermal decomposition and glass transition were also shifted to higher temperatures when inorganic functionalities were incorporated into polyurethanes.

  13. Bacterial isolates degrading aliphatic polycarbonates.

    Science.gov (United States)

    Suyama, T; Hosoya, H; Tokiwa, Y

    1998-04-15

    Bacteria that degrade an aliphatic polycarbonate, poly(hexamethylene carbonate), were isolated from river water in Ibaraki. Prefecture, Japan, after enrichment in liquid medium containing poly(hexamethylene carbonate) suspensions as carbon source, and dilution to single cells. Four of the strains, 35L, WFF52, 61A and 61B2, degraded poly(hexamethylene carbonate) on agar plate containing suspended poly(hexamethylene carbonate). Degradation of poly(hexamethylene carbonate) was confirmed by gel permeation chromatography. Besides poly(hexamethylene carbonate), the strains were found to degrade poly(tetramethylene carbonate). The strains were characterized morphologically, physiologically, and by 16S rDNA sequence analysis. Strains 35L and WFF52 were tentatively identified as Pseudomonas sp. and Variovorax sp., respectively, while strains 61A and 61B2 constitute an unidentified branch within the beta subclass of the Proteobacteria.

  14. On the Aliphatic versus Aromatic Content of the Carriers of the "Unidentified" Infrared Emission Features

    CERN Document Server

    Yang, Xuejuan; Li, Aigen; Zhong, Jianxin

    2016-01-01

    Although it is generally accepted that the so-called "unidentified" infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micrometer are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, the exact nature of their carriers remains unknown: whether they are free-flying, predominantly aromatic gas-phase molecules, or amorphous solids with a mixed aromatic/aliphatic composition are being debated. Recently, the 3.3 and 3.4 micrometer features which are commonly respectively attributed to aromatic and aliphatic C-H stretches have been used to place an upper limit of ~2\\% on the aliphatic fraction of the UIE carriers (i.e. the number of C atoms in aliphatic chains to that in aromatic rings). Here we further explore the aliphatic versus aromatic content of the UIE carriers by examining the ratio of the observed intensity of the 6.2 micrometer aromatic C-C feature (I6.2) to that of the 6.85 micrometer aliphatic C-H deformation feature (I6.85). To derive the intrinsic...

  15. Analysis Methods and Research Progress of Short Chain Chlorinated Paraffins in Soft and Sediment%土壤/沉积物中短链氯化石蜡的分析方法及研究进展

    Institute of Scientific and Technical Information of China (English)

    赵丽芳; 孟祥周; 陈玲; 陈来国

    2012-01-01

    短链氯化石蜡是由碳链长度为10~13个碳原子的正构烷烃氯化而得到的一类物质,主要用于金属切削液添加剂、皮革加脂剂和粘合剂等产品中。该类物质在环境中具有持久性、毒性、生物蓄积性和长距离迁移性,近期受到人们广泛关注。本文综述了该物质的物理化学性质、分析方法及其在全球土壤和沉积物样品中的浓度分布情况,总结了前期研究中存在的问题,为我国开展氯化石蜡的研究工作提供参考。%Short chain chlorinated paraffins (SCCPs) are obtained by chlorination of n-alkane with 10 to 13 carbon atoms, which are mainly used as additives in metal cutting fluids, fat liquoring of leather and adhesive products. They have features such as durability, toxicity, bioaccttmulation in the environment and long-distance migration, which are widely paid attention recently. In this paper the respects such as physicochemieal properties, analysis methods and global distribution in soils and sediments were reviewed. The problems in previous studies were summarized in order to provide references for the future research.

  16. Amount of aliphatic double carbon-carbon bonds in the kerogen of the Baltic shale kuckersite

    Energy Technology Data Exchange (ETDEWEB)

    Cheshko, I.D.; Kutuev, R.Kh.; Yakovlev, V.I.; Sendyurev, M.V.; Proskuryakov, V.A.

    1980-01-01

    In conclusion, among the questions of the chemical structure of the kerogen of combustible shales, one of the most important is that of the presence of multiple carbon-carbon bonds in the organic matter of these combustible minerals. In spite of a series of studies that have been performed this question has long remained open because of the contradictory opinions expressed. In the present paper, in order to evaluate the quantitative content of aliphatic bonds C-C in kerogen the authors analyze the results obtained by previous researchers in the study of the ozonization and chlorination of kuckersite, figures from balance experiments on chlorination, and the results of the use of ESR spectroscopy for these purposes and certain literature information on the halogenation of kuckersite kerogen. The presence in the kerogen of the Baltic combustible shale kuckersite of from 6 to 8 aliphatic double carbon-carbon bonds per 100 C atoms has been shown by the methods of chlorination, ozonization, and ESR spectroscopy, and this agrees with the figures calculated from certain results on the bromination of kuckersite. 18 refs.

  17. Lipase-catalyzed synthesis of oligoesters of 2,5-furandicarboxylic acid with aliphatic diols

    NARCIS (Netherlands)

    Cruz-Izquierdo, Álvaro; Broek, van den Lambertus A.M.; Serra, Juan L.; Llama, María J.; Boeriu, Carmen G.

    2015-01-01

    2,5-Furandicarboxylic acid is a platform chemical for the production of biobased polymers and materials. This study reports the synthesis of furan oligoesters via polytransesterification of dimethyl furan-2,5-dicarboxylate and linear α, ω-aliphatic diols with chain length ranging from C2 to C12,

  18. Al-Zn-Mg/Fe复合粉体降解水体中氯代有机物污染的研究%Dechlorination of Chlorinated Aliphatic Compounds by Micro-scale Al-Zn-Mg/Fe Powders as Advanced Zero-valent Iron

    Institute of Scientific and Technical Information of China (English)

    解淑民; 万平玉; A.J.Feitz; J.Guan; 杨晓波; 刘小光

    2004-01-01

    Micro-scale Al-Zn-Mg/Fe composite powders (MAF) with high reactivity and good storage properties were prepared by reducing iron onto the surface of Al-Zn-Mg alloy powders. Experimental results show that MAF as advanced zero-valent iron are highly effective for degradation of chlorinated organic compounds. The efficiency of degradation for carbon tetrachloride and perchloroethylene is higher than 99% within a period of 2 h. The efficiency of degradation for trichloroethylene by MAF after storing for one month is equivalent to that by freshly prepared nano-size zero-valent iron particles.

  19. GC Determination of Short-Chain Chlorinated Paraffin in Rubber Products%气相色谱法测定橡胶制品中短链氯化石蜡含量

    Institute of Scientific and Technical Information of China (English)

    袁丽凤; 邬蓓蕾; 罗川; 徐善浩; 华正江; 王豪

    2012-01-01

    The contents of short-chain chlorinated paraffin (C10--C13 ) in rubber products were determined by CA2 with electron capture detector. The sample was extracted ultrasonically with a mixture of n-hexane and acetone (lq-1) and separated on HP-5 quartz capillary column (30 m × 0. 35 mm, 0. 25 μm). Linear relationship between values of peak area and mass concentration of short-chain chlorinated paraffin was obtained in the range within 100 mg· L-1 , with lower limits of determination of 20 mg · kg-1 Values of recovery found were in range of 92.4%-100. 4%, and values of RSD's (n=6) found were in range of 1.8%-4. 5%.%提出了气相色谱法测定橡胶制品中短链氯化石蜡(C10~C13)含量的方法。样品经正己烷一丙酮(1+1)混合溶液超声提取,采用HP-5石英毛细管色谱柱(30m×0.35mm,0.25μm)分离,电子捕获检测器检测。短链氯化石蜡的质量浓度在100mg·L-1以内与其峰面积呈线性关系,测定下限为20mg·kg-1。方法的回收率在92.4%~100.4%之间,相对标准偏差(n=6)在1.89/5~4.5%之间。

  20. 短链氯化石蜡毒性效应及检测技术研究进展%Research advances on toxic effect and detection technology of short chain chlorinated paraffins

    Institute of Scientific and Technical Information of China (English)

    杨立新; 刘印平; 王丽英; 路杨; 张永茂

    2015-01-01

    链氯化石蜡(short chain chlorinated paraffins, SCPPs)是一类结构复杂的混合物,在工业生产中用途广泛,主要用作金属加工润滑剂、PVC 增塑剂、高分子材料阻燃剂、油漆、密封剂、粘合剂等。本文对短链氯化石蜡的毒性效应和环境污染现状进行了综述。研究了SCCPs对于哺乳动物、鱼类和两栖类、鸟类的毒理学效应,指出了毒理学领域存在的问题及研究需求。文章还对SCCPs作为持久性有机污染物的特性(持久性、生物蓄积性及长距离迁移性)以及SCCPs在环境介质(水、土壤和底泥、大气、食品)中的污染状况和检测技术进行了阐述。并总结了SCCPs研究中存在的问题,指出SCCPs的检测方法仍然是环境中SCCPs研究存在的突出问题。%ABSTRACT:Short chain chlorinated paraffins (SCPPs) is a class of complex mixtures, which is widely used in industrial production, such as metal processing lubricants, PVC increase plasticizer, flame retardant polymeric materials agent, paint, sealants, adhesives and so on. In this paper, the toxic effect of SCPPs and its environmental pollution were summarized. The toxicological effects of SCCPs on mammals, fish, amphibians and birds were studied. As a class of persistent organic pollutants, the article also described the characteristics of persistence, bioaccumulation and long distance migration for SCCPs and its pollution in environmental media (water, soil and sediment, air, food) as well as its detection method. At last, we summarized the existing problems in SCCPs research, and pointed out that the detection method of SCCPs was still a prominent problem.

  1. GC-MS测定纺织品或皮革中的短链氯化石蜡%Determination of Short- chain chlorinated paraffins in Textiles or Leather by GC- MS

    Institute of Scientific and Technical Information of China (English)

    花金龙; 廖帼英; 杨欣卉; 张建扬

    2012-01-01

    The test method based on gas ehromatography coupled with mass spectrometry was established to determine the content of short-chain chlorinated paraffins in textiles or leather, which were ultrasonically extracted with n-hexane, filtered by 0.45 μm membrane for organic phase. The type of column was selected and the extraction conditions were optimized. The method was linear with the range of the study herein, with the correlation coefficient is 0.9995. Tests for recovery and precision were made by addition of standard solutions of 11 kinds of substances very high concerned in different concentrations to samples which were then analyzed by the proposed method. Values of recovery obtained were in the range of 90.42% -94.22% with value of RSD% less than 10%. This method was rapid, accurate and sensitive. The detection limit of short-chain chlorinated paraffins was 1.5 μg/mLo%以正己烷为提取溶剂,超声提取,0.45 μm有机相微孔滤膜过滤,建立了气相色谱-质谱联用技术测定纺织品或皮革中短链氯化石蜡的检测方法.对色谱柱类型进行了选择,并对提取条件进行了优化.在本文研究范围内标准曲线呈线性关系,相关系数0.9995.进行了不同浓度的加标回收率实验,测得回收率均在90.42%~94.22%,相对标准偏差小于10%.该方法简便快捷、灵敏度高,测定低限为1.5μg/mL.

  2. Application of Pseudomonas sp. strain DCA1 for the removal of chlorinated hydrocarbons

    NARCIS (Netherlands)

    Hage, J.C.

    2004-01-01

    The large-scale application of chlorinated aliphatic hydrocarbons (CAHs) has resulted in many cases of groundwater contamination. Contaminated groundwater can be remediated by pump-and-treat: the groundwater is pumped to the surface and treated. The groundwater can be treated in bioreactors, in whic

  3. Kinetics of Chlorinated Hydrocarbon Degradation by Methylosinus trichosporium OB3b and Toxicity of Trichloroethylene

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Oedzes, Johannes Y.; Waarde, Jacob J. van der; Janssen, Dick B.

    1991-01-01

    The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were re

  4. 短链氯化石蜡急性暴露对SD雄性大鼠的组织病理学影响%Influence on Rats' Histopathology Under Exposing of Short Chain Chlorinated Paraffins

    Institute of Scientific and Technical Information of China (English)

    李勋; 刘钰晨; 陈敏杰; 李佳; 梁勇

    2013-01-01

    Objective:Chooses two chlorinated paraffins products which contain different con-tent of short chain chlorinated paraffins(SCCP)as model compound(CPsⅠ,38.22% and CPsⅡ, 0.08%),compares their influence on SD male rats after continuously 14 days being exposed through oral intragastric administration,according to that,to explore whether there is special toxicity of SC-CP or not. Methods:The exposing concentration are 10,50,100(CPsⅠ),100(CPsⅡ)mg/kg,re-spectively. Results:After being exposed under two chlorinated paraffins,there is no obvious influ-ence on food intaking and weight. CPsⅠand CPsⅡ acute exposing,can cause hepatocyte swelling, hydropic degeneration,cytoplast loosen;and renal tubule swelling,glomerulus atrophy,glomerulus hyalinosis;and alveolar septum incrassation,inflammatory cell infiltration;and so on histopatholo-gy changes. Conclusion:Acute chlorinated paraffines exposing has toxicity to SD male rats,the ef-fect has no significant relationship with the content of SCCP.%目的:选择短链氯化石蜡含量不同的两种氯化石蜡产品(CPsⅠ,38.22%和CPsⅡ,0.08%)作为模式化合物,比较它们经口连续灌胃暴露14 d后对SD雄性大鼠的影响,借以探讨短链氯化石蜡是否存在特殊的毒性效应。方法:CPsⅠ和CPsⅡ的暴露浓度分别为10、50、100 mg/kg(CPsⅠ)和100 mg/kg (CPsⅡ)。结果:两种氯化石蜡产品暴露后,对大鼠的摄食、体重无明显影响。CPsⅠ和CPsⅡ急性暴露,均可造成大鼠的肝脏中肝细胞肿胀、水样变性及胞质疏散;肾脏中肾小管肿胀,肾小球萎缩、肾小球玻璃样变;肺部中肺泡隔增厚,炎症细胞浸润等明显的组织病理学改变。结论:氯化石蜡急性暴露对SD雄性大鼠所产生的毒性效应,与样品中短链氯化石蜡的含量并无显著性关联。

  5. Clustering chlorine reactivity of haloacetic acid precursors in inland lakes.

    Science.gov (United States)

    Zeng, Teng; Arnold, William A

    2014-01-01

    Dissolved organic matter (DOM) represents the major pool of organic precursors for harmful disinfection byproducts, such as haloacetic acids (HAAs), formed during drinking water chlorination, but much of it remains molecularly uncharacterized. Knowledge of model precursors is thus a prerequisite for understanding the more complex whole water DOM. The utility of HAA formation potential data from model DOM precursors, however, is limited due to the lack of comparability to water samples. In this study, the formation kinetics of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two predominant HAA species, were delineated upon chlorination of seventeen model DOM precursors and sixty-eight inland lake water samples collected from the Upper Midwest region of the United States. Of particular interest was the finding that the DCAA and TCAA formation rate constants could be grouped into four statistically distinct clusters reflecting the core structural features of model DOM precursors (i.e., non-β-diketone aliphatics, β-diketone aliphatics, non-β-diketone phenolics, and β-diketone phenolics). A comparative approach built upon hierarchical cluster analysis was developed to gain further insight into the chlorine reactivity patterns of HAA precursors in inland lake waters as defined by the relative proximity to four model precursor clusters. This work highlights the potential for implementing an integrated kinetic-clustering approach to constrain the chlorine reactivity of DOM in source waters.

  6. Thermal Properties of Aliphatic Polypeptoids

    Directory of Open Access Journals (Sweden)

    Corinna Fetsch

    2013-01-01

    Full Text Available A series of polypeptoid homopolymers bearing short (C1–C5 side chains of degrees of polymerization of 10–100 are studied with respect to thermal stability, glass transition and melting points. Thermogravimetric analysis of polypeptoids suggests stability to >200 °C. The study of the glass transition temperatures by differential scanning calorimetry revealed two dependencies. On the one hand an extension of the side chain by constant degree of polymerization decrease the glass transition temperatures (Tg and on the other hand a raise of the degree of polymerization by constant side chain length leads to an increase of the Tg to a constant value. Melting points were observed for polypeptoids with a side chain comprising not less than three methyl carbon atoms. X-ray diffraction of polysarcosine and poly(N-ethylglycine corroborates the observed lack of melting points and thus, their amorphous nature. Diffractograms of the other investigated polypeptoids imply that crystalline domains exist in the polymer powder.

  7. Thermal Properties of Aliphatic Polypeptoids

    KAUST Repository

    Fetsch, Corinna

    2013-01-29

    A series of polypeptoid homopolymers bearing short (C1-C5) side chains of degrees of polymerization of 10-100 are studied with respect to thermal stability, glass transition and melting points. Thermogravimetric analysis of polypeptoids suggests stability to >200 °C. The study of the glass transition temperatures by differential scanning calorimetry revealed two dependencies. On the one hand an extension of the side chain by constant degree of polymerization decrease the glass transition temperatures (Tg) and on the other hand a raise of the degree of polymerization by constant side chain length leads to an increase of the Tg to a constant value. Melting points were observed for polypeptoids with a side chain comprising not less than three methyl carbon atoms. X-ray diffraction of polysarcosine and poly(N-ethylglycine) corroborates the observed lack of melting points and thus, their amorphous nature. Diffractograms of the other investigated polypeptoids imply that crystalline domains exist in the polymer powder. © 2013 by the authors.

  8. BIOACCUMULATION CHARACTERISTICS OF SHORT-CHAIN CHLORINATED PARAFFINS IN LIAODONG BAY,NORTHEAST CHINA%辽东湾海域短链氯化石蜡的生物累积特征

    Institute of Scientific and Technical Information of China (English)

    王成; 高媛; 张海军; 樊景凤; 陈吉平

    2011-01-01

    In order to know the pollution status of short-chain chlorinated paraffins (SCCPs) in China seas,organism samples including plankton, 8 kinds of benthic organism ( shrimp, crab, clam, scallop, and trumpet shell) and 6 kinds of fish were collected from the sea area of Liaodong Bay in 2009. SCCPs in these organism samples were analyzed using gas chromatography/electron capture negative chemical ionization low-resolution mass spectrometry (HRGC/ECNI-LRMS). The total concentrations of SCCPs in these organism samples were determined to be in the range of 0.66-20.32 μg·g-1 dw. C10-SCCPs and C11-SCCPs predominated over the SCCPs compounds in 15 kinds of organism samples, and the relative concentration of C13-SCCPs was lowest.Meanwhile, the accumulative levels of lower chlorinated (penta- and hexa-chlorinited) C10-SCCPs and C11SCCPs in most of collected organism samples were found to be higher.%为了解短链氯化石蜡(SCCPs)在我国海域的污染现状,于2009年采集了渤海辽东湾海域的浮游动物、8种底栖动物(虾、蟹、蛤、扇贝和螺)和6种鱼类,采用高分辨气相色谱/电子捕获负离子化-低分辨质谱(HRGC/ECNI-LRMS)分析了其中的SCCPs.结果表明,渤海辽东湾海域水生动物体中SCCPs的含量变化范围为O.66-20.32 μg·g-1dw(干重).采集的15种水生动物样品中SCCPs以C10-SCCPs和C11-SCCPs为主,C13-SCCPs含量最低,并且低氯取代(五氯和六氯)的C10-SCCPs和C11-SCCPs在绝大多数生物体内累积量较高.

  9. Spatial distribution of short chain chlorinated paraffins in soils from Taizhou, an e-waste dismantling area%短链氯化石蜡在台州电子拆解地区的分布特征

    Institute of Scientific and Technical Information of China (English)

    陈茹; 王亚韡; 王璞; 江桂斌

    2014-01-01

    以峰江为中心,采集了台州电子垃圾拆解区域的26个表层土壤样品,调查台州地区短链氯化石蜡( SCCPs)的污染状况、空间分布和单体构成情况.结果表明, SCCPs在所有土壤样品中均有检出,其浓度水平介于47�95-1298 ng·g-1干重,平均值为276.7 ng·g-1干重. C10和Cl6-7为土壤中SCCPs最主要的碳原子和氯原子同族体.空间分布表明短链氯化石蜡的浓度水平总体呈现随距采样点中心峰江距离增加而减少的趋势,说明电子垃圾拆解活动可能是SCCPs的一个潜在释放源.%Taizhou is a major e-waste dismantling area in China. A large quantity of contaminants in the electronic and electrical equipments can be released to the ambient environment through the unregulated e-waste dismantling activities. In this study, 26 soil samples from Fengjiang, a typical e-waste dismantling site in Taizhou, were collected in 2008-2009 to investigate the pollution levels, spatial distribution and congener patterns of short chain chlorinated paraffins ( SCCPs) in the soils. SCCPs were detected in all soil samples, with the total concentrations ranging from 47.95 to 1298 ng·g-1 dw (mean value of 276.7 ng·g-1). The chlorine content of SCCPs in soil samples were in the range of 59.1%-62.8%. C10 and Cl6,7 were the dominant homologue groups among all SCCPs congeners. A significant decreasing trend of the total concentrations of∑SCCPs was found in the soil samples with increasing distance from Fengjiang, suggesting that e-waste dismantling activities might be a major source of SCCPs released to the ambient environment.

  10. Analysis of Short Chain Chlorinated Paraffins in Leather by Liquid Chromatography-Atmosphere Pressure Ionization Mass Spectrometry%皮革中短链氯化石蜡的液相色谱-大气压化学电离质谱分析

    Institute of Scientific and Technical Information of China (English)

    马贺伟

    2012-01-01

    Short - chain chlorinated paraffins ( SCCPs) in leather were analyzed by liquid chromatography combined atmosphere pressure ionization mass spectrometry ( LC - APCI/MS). The results demonstrated that multi - clusters of chloride adduct ions were contained in the mass spectrum and the response factors were dependent on the degree of chlorination. Selective Ion Monitoring (SIM) mode could reduce the interferences of medium - chain chlorinated paraffins (MCCPs). However, the significant interferences were found when leather samples were tested due to the expressive complexity of the matrix in leather, which easily resulted in FALSE positives.%采用液相色谱-大气压化学电离源质谱(LC-MS/APCI)对皮革中短链氯化石蜡(SCCPs)进行分析.结果表明,SCCPs的质谱图包含了多簇离子碎片峰,其响应值表现出对氯含量的依赖性;采用选择监测离子模式可有效降低中链氯化石蜡(MCCPs)的干扰,但实际皮革样品基质的多样性及复杂性,极易造成检测结果的假阳性.

  11. Notch sensitivity of aliphatic polyketone terpolymers

    NARCIS (Netherlands)

    Zuiderduin, W.C.J.; Huetink, J.; Gaymans, R.J.

    2004-01-01

    The notch sensitivity of aliphatic polyketone (PK) terpolymers was investigated in this article. The notch-tip radius was varied between the size of an actual propagating crack tip of 1-2 m and the largest notch tip of 1000 m radius. The larger notch-tip radii (1000-15 m) were milled into the polyme

  12. CCN activity of aliphatic amine secondary aerosol

    Directory of Open Access Journals (Sweden)

    X. Tang

    2014-01-01

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

  13. Spatial and temporal variability in air concentrations of short-chain (C10-C13) and medium-chain (C14-C17) chlorinated n-alkanes measured in the U.K. atmosphere.

    Science.gov (United States)

    Barber, Jonathan L; Sweetman, Andy J; Thomas, Gareth O; Braekevelt, Eric; Stern, Gary A; Jones, Kevin C

    2005-06-15

    Two studies were carried out on short-chain (C10-C13) and medium-chain (C14-C17) polychlorinated n-alkanes (sPCAs and mPCAs) in U.K. air samples. The first study entailed taking 20 24-h air samples with a pair of Hi-Vol air samplers at the Hazelrigg field station, near Lancaster University. These samples were carefully selected to coincide with times when air masses were predicted to have a fairly constant back trajectory for 24 h and to give a broad spectrum of different origins. The second study was a spatial survey of PCAs in the air at 20 outdoor sites in northern England and four indoor locations in Lancaster, using polyurethane foam (PUF) disk passive air samplers. Levels of the sPCAs in the Hi-Vol samples ranged from <185 to 3430 pg m(-3) (average 1130 pg m(-3)) and were higher than those previously measured at this site in 1997. Levels of the mPCAs ranged from <811 to 14500 pg m(-3) (average 3040 pg m(-3)); that is, they were higher than sPCAs. Both sPCA and mPCA air concentrations are of the same order of magnitude as PAH at this site. Back trajectory analysis showed that the history of the air mass in the 48 h prior to sampling had an important effect on the concentrations observed, with overland samples having higher levels than oceanic, implying that the U.K. is probably responsible for most of the PCAs measured in the U.K. atmosphere. Amounts of both sPCAs and mPCAs in the passive air samples followed a rural-urban gradient. PCAs appear to be released from multiple sources around the country, as a result of the diffusive, open industrial and construction use of the technical mixtures.

  14. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  15. 不同链结构的双酚A聚碳酸酯对脂肪族聚碳酸酯结晶行为的影响%EFFECT OF BISPHENOL A POLYCARBONATE WITH DIFFERENT CHAIN STRUCTURE ON THE CRYSTALLIZATION BEHAVIOR OF ALIPHATIC POLYCARBONATE

    Institute of Scientific and Technical Information of China (English)

    宁炜; 刘琛阳; 朱文祥; 李春成; 王笃金

    2012-01-01

    脂肪族聚碳酸酯(APC)是一类可降解的高分子材料,因其生产工艺可固定温室气体的主要成分二氧化碳,这种可降解塑料得到了越来越多的关注.作为半结晶高分子材料,脂肪族聚碳酸酯的结晶性能和结晶结构对成型加工、力学性能和降解性能具有重要的影响.借助热分析(示差扫描量热仪DSC)和形态学观察(偏光显微镜POM)两种方法研究了不同链结构的双酚A型聚碳酸酯对半结晶脂肪族聚碳酸酯——聚碳酸1,4-丁二醇酯结晶动力学行为的影响.实验发现质量分数1%的双酚A聚碳酸酯的加入促进了聚碳酸1,4-丁二醇酯的成核,但不同链结构的双酚A聚碳酸酯对其晶体生长具有相反的作用,线形双酚A聚碳酸酯(PC-L)能够促进晶体生长,而支化双酚A聚碳酸酯(PC-B)则抑制晶体生长.用原子力显微镜在轻敲模式下研究了两种双酚A聚碳酸酯与APC共混物熔融状态下的相结构,发现熔体结构的不同是导致两种共混物与纯的APC相比,结晶速率呈现相反变化趋势的主要原因.%In the present investigation, the effect of the chain structure and aggregation state of bisphenol A polycarbonate ( PC) on the crystallization kinetics and morphology of the poly ( butylene carbonate) has been studied by DSC and POM. It was found that the addition of bisphenol A polycarbonate A promoted the nucleation of the poly( butylene carbonate) , while the chain structure of PC had the opposite influence on the crystal growth rate of the poly ( butylene carbonate). The linear bisphenol A polycarbonate polycarbonate accelerates the crystal growth rate of poly ( butylene carbonate) , while the long chain-branched bisphenol A polycarbonate decelerates it. The phase images of the blends of aliphatic polycarbonates and bisphenol A polycarbonate were obtained under the tapping mode by atomic force microscopy ( AFM). The linear bisphenol A polycarbonate shows isolated irregular

  16. Study on Aromatization of C6 Aliphatic Hydrocarbons on ZRP Zeolite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Xie Chaogang

    2004-01-01

    The performance of ZRP zeolite catalysts for aromatization of C6 aliphatic hydrocarbons was investigated in a pulsed microreactor. The influence of metal modified ZRP zeolites on aromatization reaction was also studied, coupled with comparison of aromatization tendencies of olefins, paraffins and paraffins with different degrees of chain branching. Test results had shown that the lower the silicon/aluminum ratio in the ZRP zeolite, the higher the aromatization reactivity of aliphatic hydrocarbons. Modification of ZRP zeolite by zinc and its zinc content had apparent impact on the yield and distribution of aromatics. The aromatization tendency of olefins was apparently better than paraffins, while the aromatization tendency of monomethyl paraffins was better than that of straight-chain paraffins with the exception of dimethyl paraffins, which had worse aromatization tendency because of their steric hindrance.

  17. Water Treatment Technology - Chlorination.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chlorination provides instructional materials for nine competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of chlorination, chlorine…

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

    Science.gov (United States)

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

    2016-10-01

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

  19. Scientific Opinion on Flavouring Group Evaluation 63, Revision 1 (FGE.63Rev1: Consideration of aliphatic secondary alcohols, ketones and related esters evaluated by JECFA (59th and 69th meetings structurally related to saturated and unsaturated aliphatic secondary alcohols, ketones and esters of secondary alcohols and saturated linear or branched-chain carboxylic acids evaluated by EFSA in FGE.07Rev4 (2012

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2012-10-01

    Full Text Available

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA, and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC No 1565/2000. The present consideration concerns a group of 19 aliphatic secondary alcohols, ketones and related esters evaluated by the JECFA at the 59th and 69th meetings in 2002 and 2008. This revision is made due to inclusion of six additional substances, 4,8-dimethyl-3,7-nonadien-2-ol, 6-methylhepta-3,5-dien-2-one, octa-1,5-dien-3-one, (E,E-3,5-octadien-2-one, (3Z-4,8-dimethyl-3,7-nonadiene-2-one and 4,8-dimethyl-3,7-nonadien-2-yl acetate [FL-no: 02.252, 07.099, 07.190, 07.247, 07.256 and 09.936] cleared for genotoxicity concern. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel agrees with the application of the Procedure as performed by the JECFA for all 19 substances considered in this FGE and agrees with the JECFA conclusion, “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach.

  20. A New Form of Triple-Stranded Helicate Found in Uranyl Complexes of Aliphatic α,ω-Dicarboxylates.

    Science.gov (United States)

    Thuéry, Pierre; Harrowfield, Jack

    2015-11-16

    The reaction of uranyl ions with azelaic or dodecanedioic acids under solvohydrothermal conditions leads to crystallization of anionic dinuclear cage compounds with [M(bipy/phen)3](2+) counterions (M = 3d-block cation), while the smaller suberic acid yields heterometallic metallacycles. Complexes with the longer aliphatic chains are the first triple-stranded helicates reported in actinide chemistry.

  1. Structural characterisation of aliphatic, non-hydrolyzable biopolymers in freshwater algae and a leaf cuticle by ruthenium tetroxide degradation

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schouten, S.; Moerkerken, P.; Gelin, F.; Baas, M.; Leeuw, J.W. de

    1998-01-01

    Aliphatic, non-hydrolyzable biopolymers were subjected to RuO4-oxidation in order to examine the potential of this method in revealing details on their structures. The method was tested on model compounds first and found to cleave alkyl chains of aromatic moieties, double bonds and ether bonds. Oxid

  2. The Short-chain Chlorinated Paraffins Content and distribution in soil of Guangzhou%广州土壤中短链氯化石蜡的含量水平和分布特征

    Institute of Scientific and Technical Information of China (English)

    韩双; 黄玉妹; 陈来国; 叶芝祥; 封永斌; 张素坤

    2012-01-01

    短链氯化石蜡(SCCPs)是一类新的持久性有机污染物(POPs),目前我国相关研究较少。为了解SCCPs在土壤中的污染现状和分布特征,测定了24个广州土样(含3个剖面采样点)中SCCPs的含量,分析了其同族体分布模式。结果表明:广州表层土壤中SCCPs的含量变化范围为6.8~541.2ng/g,均值为79.6ng/g;剖面土壤中SCCPs的含量范围为7.5~115.8ng/g,均值为33.1ng/g。不同类型土壤中SCCPs各同系物组分的分布模式相似,以碳原子数为10和11的Cl6-SCCPs/Cl7-SCCPs为主。%Short-chain chlorinated paraflqns (SCCPs) are a new kind of persistent organic pollutants (POPs), on which the studies are insufficient in China. In this paper, to control the pollution situation and distribution of SCCPs in soils, 24 soil samples from three sampling sections in Guangzhou were determined. The distribution modes of SCCPs homologues were analyzed. The results showed that in Guangzhou the SCCPs content in surface soil ranged in 6. 8 - 541.2 ng/g with an average value of 79. 6 ng/g and that for the profile soil ranging in 7. 5 - 115.8 ng/g with an average value of 33. 1 ng/g. The SCCP homologues were distributed similarly in different kind of soil, mainly consisting of C16-SCCPs/C17- SCCPs with 10 or 11 carbon atoms.

  3. Thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene and aliphatic dicarboxylic acid chlorides

    Indian Academy of Sciences (India)

    Khudbudin Mulani; Mohasin Momin; Nitin Ganjave; Nayaku Chavan

    2015-09-01

    A series of thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene (BHBOMB) and aliphatic dicarboxylic acid chlorides were investigated. All these polyesters were synthesized by interfacial polycondensation method and characterized by differential scanning calorimetry and wide-angle X-ray diffractometer. These polyesters consist of BHBOMB as a mesogenic diol and aliphatic diacid chlorides were used as flexible spacers. The length of oligomethylene units in polymer was varied from the trimethylene to the dodecamethylene groups. The transition temperatures and thermodynamic properties were studied for all these polymers. All these polyesters were soluble in chlorinated solvents such as chloroform, dichloromethane, dichloroethane, etc. More importantly, all these polyesters exhibited very large mesophase stability.

  4. Attachment of inorganic moieties onto aliphatic polyurethanes

    OpenAIRE

    Eliane Ayres; Wander Luiz Vasconcelos; Rodrigo Lambert Oréfice

    2007-01-01

    Polyurethanes have been used in a series of applications due basically to their versatility in terms of controlling the behavior by altering basically the type of reagents used. However, for more specific and advanced applications, such as in membranes, biomaterials and sensors, well-organized and defined chemical functionalities are necessary. In this work, inorganic functionalities were incorporated into aliphatic polyurethanes (PU) having different macromolecular architectures. Polyurethan...

  5. CCN activity of aliphatic amine secondary aerosol

    Science.gov (United States)

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

    2014-01-01

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

  6. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxi...

  7. Olfactory sensitivity and odor structure-activity relationships for aliphatic carboxylic acids in CD-1 mice.

    Science.gov (United States)

    Can Güven, Selçuk; Laska, Matthias

    2012-01-01

    Using a conditioning paradigm, the olfactory sensitivity of CD-1 mice for a homologous series of aliphatic n-carboxylic acids (ethanoic acid to n-octanoic acid) and several of their isomeric forms was investigated. With all 14 odorants, the animals significantly discriminated concentrations as low as 0.03 ppm (parts per million) from the solvent, and with four odorants the best-scoring animals even detected concentrations as low as 3 ppt (parts per trillion). Analysis of odor structure-activity relationships showed that the correlation between olfactory detection thresholds of the mice for the unbranched carboxylic acids and carbon chain length can best be described as a U-shaped function with the lowest threshold values at n-butanoic acid. A significant positive correlation between olfactory detection thresholds and carbon chain length of the carboxylic acids with their branching next to the functional carboxyl group was found. In contrast, no such correlation was found for carboxylic acids with their branching at the distal end of the carbon chain relative to the functional carboxyl group. Finally, a significant correlation was found between olfactory detection thresholds and the position of the branching of the carboxylic acids. Across-species comparisons suggest that mice are more sensitive for short-chained (C(2) to C(4)) aliphatic n-carboxylic acids than other mammalian species, but not for longer-chained ones (C(5) to C(8)). Further comparisons suggest that odor structure-activity relationships are both substance class- and species-specific.

  8. Bioluminescence inhibition of bacterial luciferase by aliphatic alcohol, amine and carboxylic acid: inhibition potency and mechanism.

    Science.gov (United States)

    Yamasaki, Shinya; Yamada, Shuto; Takehara, Kô

    2013-01-01

    The inhibitory effects of hydrophobic molecules on the bacterial luciferase, BL, luminescence reaction were analyzed using an electrochemically-controlled BL luminescence system. The inhibition potency of alkyl amines, C(n)NH(2), and fatty acids, C(m)COOH (m = n - 1), on the BL reaction increased with an increase in the alkyl chain-length of these aliphatic compounds. C(m)COOH showed lower inhibition potency than C(n)NH(2) and alkyl alcohols, C(n)OH, data for which have been previously reported. To make clear the inhibition mechanisms of the aliphatic compounds on the BL reaction, the initial rate of the BL reaction was measured and analyzed using the Dixon plot and Cornish-Bowden plot. The C(12)OH inhibited the BL reaction in competition with the substrate C(11)CHO, while C(12)NH(2) and C(11)COOH inhibited in an uncompetitive manner with the C(11)CHO. These results suggest that the alkyl chain-length and the terminal unit of the aliphatic compound determine the inhibition potency and the inhibition mechanism, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczak, Malgorzata; Galeski, Andrzej; Piorkowska, Ewa [Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland); Dutkiewicz, Slawomir [Institute of Biopolymers and Chemical Fibres, Marii Sklodowskiej-Curie 19/27, 90-570 Lodz (Poland)

    2014-05-15

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

  10. Fate of chlorinated fatty acids in migrating sockeye salmon and their transfer to arctic grayling

    DEFF Research Database (Denmark)

    Mu, Huiling; Ewald, G.; Nilsson, E.;

    2004-01-01

    organohalogen compounds in the salmon were halogenated fatty acids, predominantly chlorinated species that accounted for up to 35% of the extractable, organically bound chlorine (EOCl) in the fish tissues. The amount of chlorinated fatty acids in the salmon muscle decreased as a result of spawning migration....... The decrease was correlated with that of triacylglycerols in the salmon muscle, indicating the chlorinated fatty acids to be mobilized and metabolized to approximately the same extent as the other fatty acids. Chlorinated fatty acids were also transferred to the maturing roe in a manner similar...... to that of the unchlorinated fatty acids. Lipids of the Arctic grayling (Thymallus arcticus), a fish resident to the spawning lake of the salmon, contained higher concentrations of chlorinated fatty acids than grayling in a lake without migratory salmon. This may reflect a food-chain transfer of the chlorinated fatty acids...

  11. A study of aliphatic amino acids using simulated vibrational circular dichroism and Raman optical activity spectra

    CERN Document Server

    Ganesan, Aravindhan; Wang, Feng

    2013-01-01

    Vibrational optical activity (VOA) spectra, such as vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectra, of aliphatic amino acids are simulated using density functional theory (DFT) methods in both gas phase (neutral form) and solution (zwitterionic form), together with their respective infrared (IR) and Raman spectra of the amino acids. The DFT models, which are validated by excellent agreements with the available experimental Raman and ROA spectra of alanine in solution, are employed to study other aliphatic amino acids. The inferred (IR) intensive region (below 2000 cm-1) reveals the signature of alkyl side chains, whereas the Raman intensive region (above 3000 cm-1) contains the information of the functional groups in the amino acids. Furthermore, the chiral carbons of the amino acids (except for glycine) dominate the VCD and ROA spectra in the gas phase, but the methyl group vibrations produce stronger VCD and ROA signals in solution. The C-H related asymmetric vibrations domina...

  12. Interaction between hypocrellin and aliphatic amines

    Institute of Scientific and Technical Information of China (English)

    张曼华; 陈申; 夏万林; 蒋丽金; 陈德文

    1996-01-01

    The interaction of hypocrellin, including hypocrellin A (HA) and hypocrellin B (HB), with aliphatic amines in deaerated solutions has been studied by ESR and nanosecond transient absorption spectra. In polar solvents, the acid-base interaction between hypocrellin and amines was observed without irradiation. The signals of semiquinone radical anions of hypocrellm and the spin-trapping adduct of α-phenyl-N-tertbutyl-ratrone (PNB) with the aminoalkyl radicals have been detected in photoinduced ESR studies. The transient absorption of excited triplet state of HA and semiquinone radical anion of HA have been observed in laser flash photolysis studies.

  13. Aliphatic acid-conjugated antimicrobial peptides--potential agents with anti-tumor, multidrug resistance-reversing activity and enhanced stability.

    Science.gov (United States)

    Deng, Xin; Qiu, Qianqian; Ma, Ke; Wang, Xuekun; Huang, Wenlong; Qian, Hai

    2015-07-28

    Compared with traditional therapeutics, antimicrobial peptides as novel anti-tumor agents have prominent advantages of higher specificity and circumvention of multi-drug resistance. In a previous study, we found that B1, an antimicrobial peptide derived from Cathelicidin-BF15, presented specific anti-tumor activity against several tumor cells. Since aliphatic chain-conjugated peptides have shown ameliorative activity and stability, we conjugated aliphatic acids with different lengths to the amino terminal of B1. All the conjugated peptides exhibited improved anti-tumor activity over B1. Further investigations revealed that the peptides were capable of disrupting the cell membrane, stimulating cytochrome c release into the cytosol, which results in apoptosis. The peptides also acted against multidrug resistant cells and had multidrug resistance-reversing effects. Additionally, conjugation of aliphatic acid enhanced the peptide stability in plasma. In summary, aliphatic acid-modified peptides might be promising anti-tumor agents in the future.

  14. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    OpenAIRE

    Taylor, Robert H; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains wer...

  15. Gaseous aliphatic aldehydes in Chinese incense smoke

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.M.; Wang, L.H. (National Taiwan Univ., Taipei (China))

    1994-09-01

    Aliphatic aldehydes were found during the combustion of materials. Tobacco smoke contains aldehydes. Fire fighters were exposed to aldehydes when they conducted firefighting. Aldehydes in ambient air come mainly from the incomplete combustion of hydrocarbons and from photochemical reaction. Most aldehydes in ambient air are formaldehyde and acetaldehyde. Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and benzaldehyde were found in the atmosphere in Los Angeles. Burning Chinese incense for worshipping deities is a Chinese daily routine. It was suspected to be a factor causing nasopharynegeal cancer. Epidemiological studies correlated it with the high risk of childhood brain tumor and the high risk of childhood leukemia. Ames test identified the mutagenic effect of the smoke from burning Chinese incense. The smoke had bee proved to contain polycyclic aromatic hydrocarbons and aromatic aldehydes. Suspicion about formaldehyde and other alphatic aldehydes was evoked, when a survey of indoor air pollution was conducted in Taipei city. This study determined the presence of aliphatic aldehydes in the smoke from burning Chinese incense under a controlled atmosphere. 12 refs., 5 figs., 2 tabs.

  16. Push-Pull Tests for Evaluating the Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons

    Science.gov (United States)

    2005-04-13

    measurement using the same procedure. The reference sample consists of oxygen saturated distilled water , which was 24 prepared by sparging a 1 L bottle ...the Toluene-oxidizing Bacterium, Burkholderia cepacia G4. Ph.D. Thesis, Oregon State University, Corvallis, Oregon. Yeager, C. M. 2002. Inactivation...plastic tanks and carboys to hold prepared test solutions, and standard groundwater sampling equipment. The injected test solution consists of water

  17. Technical Protocol for Using Soluble Carbohydrates to Enhance Reductive Dechlorination of Chlorinated Aliphatic Hydrocarbons

    Science.gov (United States)

    2002-12-19

    subsurface injection of a soluble electron donor solution (typically comprised of a carbohydrate such as molasses, whey , high fructose corn syrup (HFCS... whey , high fructose corn syrup (HFCS), glucose, lactate, butyrate, benzoate). Other approaches to enhanced anaerobic bioremediation exist, but will...other methods for sample analysis are drawn from standard reference works such as “Standard Methods for the Examination of Water and Wastewater ” (APHA

  18. Push-Pull Tests for Evaluating the Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons

    Science.gov (United States)

    2006-09-01

    RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA .........................17 4.2 EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS...Logistics Center, Washington. 3.2.2 McClellan Site Description Field tests were performed at the site of the former McAFB near Sacramento , California...at full scale Conducted at full scale 17 4.1 EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA Transport

  19. Push-Pull Tests for Evaluating the Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons: Cost & Performance Report

    Science.gov (United States)

    2006-09-01

    EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA .........................17 4.2 EXAMPLE RESULTS FROM FIELD PUSH-PULL...Logistics Center, Washington. 3.2.2 McClellan Site Description Field tests were performed at the site of the former McAFB near Sacramento , California...Conducted at full scale Conducted at full scale 17 4.1 EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA Transport

  20. Degradation of Chlorinated Aliphatic Hydrocarbons by Methylosinus trichosporium OB3b Expressing Soluble Methane Monooxygenase

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Vink, Ruud L.J.M.; Janssen, Dick B.; Witholt, Bernard

    1989-01-01

    Degradation of trichloroethylene (TCE) by the methanotrophic bacterium Methylosinus trichosporium OB3b was studied by using cells grown in continuous culture. TCE degradation was a strictly cometabolic process, requiring the presence of a cosubstrate, preferably formate, and oxygen. M. trichosporium

  1. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Science.gov (United States)

    2010-07-01

    ... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting under... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dialkyldithiophosphoric...

  2. Reaction products of chlorine dioxide.

    Science.gov (United States)

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxide treatment of organic materials are oxidized species, some of which also contain chlorine. The relative amounts of species types may depend on the amount of chlorine dioxide residual maintained and the concentration and nature of the organic material present in the source water. The trend toward lower concentrations of chlorinated by-products with increasing ClO2 concentration, which was observed with phenols, has not been observed with natural humic materials as measured by the organic halogen parameter. Organic halogen concentrations have been shown to increase with increasing chlorine dioxide dose, but are much lower than those observed when chlorine is applied. Aldehydes have been detected as apparent by-products of chlorine dioxide oxidation reactions in a surface water that is a drinking water source. Some other nonchlorinated products of chlorine dioxide treatment may be quinones and epoxides. The extent of formation of these moieties within the macromolecular humic structure is also still unknown. PMID:7151750

  3. Formation of halogenated organic byproducts during medium-pressure UV and chlorine coexposure of model compounds, NOM and bromide.

    Science.gov (United States)

    Zhao, Quan; Shang, Chii; Zhang, Xiangru; Ding, Guoyu; Yang, Xin

    2011-12-01

    When chlorine is applied before or during UV disinfection of bromide-containing water, interactions between chlorine, bromide and UV light are inevitable. Formation of halogenated organic byproducts was studied during medium-pressure UV (MPUV) and chlorine coexposure of phenol, nitrobenzene and benzoic acid and maleic acid, chosen to represent electron-donating aromatics, electron-withdrawing aromatics, and aliphatic structures in natural organic matter (NOM), respectively. All were evaluated in the presence and absence of bromide. MPUV and chlorine coexposure of phenol produced less total organic halogen (TOX, a collective parameter for halogenated organic byproducts) than chlorination in the dark, and more haloacetic acids instead of halophenols. Increases in TOX were found in the coexposure of nitrobenzene and benzoic acid, but maleic acid was rather inert during coexposure. The presence of bromide increased the formation of brominated TOX but did not significantly affect total TOX formation, in spite of the fact that it reduced hydroxyl radical levels. MPUV and chlorine coexposure of NOM gave a higher differential UV absorbance of NOM and a larger shift to lower molecular weight compounds than chlorination in the dark. However, TOX formation with NOM remained similar to that observed from dark chlorination.

  4. Thermal stability of aliphatic hyperbranched polyesters

    Directory of Open Access Journals (Sweden)

    Vuković Jasna

    2002-01-01

    Full Text Available The influence of the molar mass (generation, number and type of end groups on the thermal stability of aliphatic hyperbranched polyesters are presented in this study. Different end groups were obtained by modification of the samples with chlorides of propionic acid and stearic acid. The thermal stability of the hyperbranched polyesters was determined by thermogravimetry using a NET-ZSCH TG 209 instrument in nitrogen atmosphere at a heating rate of 10°C/min. A comparison of the temperatures obtained for mass losses of 5 20 and 40 wt% for unmodified samples showed that the thermal stability increased up to the fourth generation and then remained practically constant. An increase in the thermal stability of modified samples of the second, third and fourth generation was observed.

  5. Chlorine dioxide and hemodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.P. (Dartmouth Coll., Hanover, NH (USA). Dept. of Pharmacology and Toxicology)

    1989-05-01

    Because it has little or no tendency to generate carcinogenic trihalomethanes such as chloroform, chlorine dioxide is an attractive alternative to chlorine for drinking water disinfection. There are, however, concerns about its acute toxicity, and the toxic effects of its by-products, chlorite and chlorate. The human experience with chlorine dioxide in both controlled, prospective studies and in actual use situations in community water supplies have as yet failed to reveal adverse health effects. The EPA has recommended standards of 0.06 mg/L for chlorine dioxide and standards of 0.007 mg/L for chlorite and chlorate in drinking water. Among groups who may be at special risk from oxychlorines in drinking water are patients who must undergro chronic extracorporeal hemodialysis. Although even units for home hemodialysis are supposed to be equipped with devices which effectively remove oxychlorines, there is a always a possibility of operator error or equipment failure. When the equipment is adequately maintained, it is likely that dialysis patients will have more intensive exposures from drinking water than from dialysis fluids despite the much larger volumes of water that are involved in dialysis. This paper discusses a hemodialysis and the standards and effects of oxychlorines. 90 refs., 2 tabs.

  6. Development of aliphatic biodegradable photoluminescent polymers

    Science.gov (United States)

    Yang, Jian; Zhang, Yi; Gautam, Santosh; Liu, Li; Dey, Jagannath; Chen, Wei; Mason, Ralph P.; Serrano, Carlos A.; Schug, Kevin A.; Tang, Liping

    2009-01-01

    None of the current biodegradable polymers can function as both implant materials and fluorescent imaging probes. The objective of this study was to develop aliphatic biodegradable photoluminescent polymers (BPLPs) and their associated cross-linked variants (CBPLPs) for biomedical applications. BPLPs are degradable oligomers synthesized from biocompatible monomers including citric acid, aliphatic diols, and various amino acids via a convenient and cost-effective polycondensation reaction. BPLPs can be further cross-linked into elastomeric cross-linked polymers, CBPLPs. We have shown representatively that BPLP-cysteine (BPLP-Cys) and BPLP-serine (BPLP-Ser) offer advantages over the traditional fluorescent organic dyes and quantum dots because of their preliminarily demonstrated cytocompatibility in vitro, minimal chronic inflammatory responses in vivo, controlled degradability and high quantum yields (up to 62.33%), tunable fluorescence emission (up to 725 nm), and photostability. The tensile strength of CBPLP-Cys film ranged from 3.25 ± 0.13 MPa to 6.5 ± 0.8 MPa and the initial Modulus was in a range of 3.34 ± 0.15 MPa to 7.02 ± 1.40 MPa. Elastic CBPLP-Cys could be elongated up to 240 ± 36%. The compressive modulus of BPLP-Cys (0.6) (1:1:0.6 OD:CA:Cys) porous scaffold was 39.60 ± 5.90 KPa confirming the soft nature of the scaffolds. BPLPs also possess great processability for micro/nano-fabrication. We demonstrate the feasibility of using BPLP-Ser nanoparticles (“biodegradable quantum dots”) for in vitro cellular labeling and noninvasive in vivo imaging of tissue engineering scaffolds. The development of BPLPs and CBPLPs represents a new direction in developing fluorescent biomaterials and could impact tissue engineering, drug delivery, bioimaging. PMID:19506254

  7. Production of hydrogen by Clostridium species in the presence of chlorinated solvents.

    Science.gov (United States)

    Bowman, Kimberly S; Rainey, Fred A; Moe, William M

    2009-01-01

    Although anaerobic bioremediation of chlorinated organic contaminants in the environment often requires exogenous supply of hydrogen as an electron donor, little is known about the ability of hydrogen-producing bacteria to grow in the presence of chlorinated solvents. In this study, 18 Clostridium strains including nine uncharacterized isolates originating from chlorinated solvent contaminated groundwater were tested to determine their ability to fermentatively produce hydrogen in the presence of three common chlorinated aliphatic groundwater contaminants: 1,2-dichloroethane (DCA), 1,1,2-trichloroethane (TCA), and tetrachloroethene (PCE). All strains produced hydrogen in the presence of at least 7.4 mM DCA, 2.4 mM TCA, and 0.31 mM PCE. Some strains produced hydrogen in media containing concentrations as high as 29.7 mM DCA, 9.8 mM TCA, and 1.1 mM PCE. None of the strains biotransformed chlorinated solvents under the conditions tested. Results demonstrate that many Clostridium species are chlorinated solvent tolerant, producing hydrogen even in the presence of high concentrations of DCA, TCA, and PCE. These findings have important implications for bioremediation of contaminated soil and groundwater.

  8. Solid state and sub-cooled liquid vapour pressures of cyclic aliphatic dicarboxylic acids

    Directory of Open Access Journals (Sweden)

    A. M. Booth

    2010-10-01

    Full Text Available Knudsen Effusion Mass Spectrometry (KEMS has been used to measure for the first time the solid state vapour pressures of a series of aliphatic cyclic dicarboxylic acids with increasing ring size. Additionally the atmospherically important compounds; cis-pinonic acid and levoglucosan were also measured. Differential Scanning Calorimetry (DSC was used to measure melting points, enthalpies and entropies of fusion, which were used to determine sub-cooled liquid vapour pressures for the compounds. The sub-cooled liquid vapour pressure of straight chain, branched and cyclic dicarboxylic acids was compared to a selection of estimation methods.

  9. Strong Room-Temperature Photoluminescence from the Novel Adduct of C60 with Aliphatic Amines

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Strong room-temperature photoluminescence from the adducts of C60 reacting with five different aliphatic amines, namely propylethylamine (PPA), n-butyl amine (BTA), n-heptylamine (HPA) and dodecylamine (DDA) and diethylamine (DEA), was firstly found from their toluene solution at relatively shorter wavelength around 519 nm.The fluorescence intensity has a good correlation with the length of n-alkyl group chain, the steric position and concentration of different amines and setting of solution as well as the UV-radiation. Their fluorescence quenching by concentration and by aromatic electron-donor N,N-dimethylaniline (DMA) were first investigated and determined.

  10. Reactions of aqueous chlorine and chlorine dioxide with model food compounds.

    OpenAIRE

    Fukayama, M Y; Tan, H; Wheeler, W B; Wei, C I

    1986-01-01

    Chlorine and chlorine dioxide (ClO2), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing and chlorinating agents. Unfortunately, little is known about the nature of the reactions of chlorine with organic food constituents. This presentation reviews published information concerning the reactions of chlorine gas (Cl2[g]), aqueous chlorine, and ClO2 with model food compounds, the fate of chlorine during the chlorination of specific food products, and the ...

  11. Chlorine-36 and chlorine concentrations within several compartments of a deciduous forest ecosystem in Meuse/Haute-Marne (France)

    Science.gov (United States)

    Pupier, Julie; Benedetti, Lucilla; Bourles, Didier; Leclerc, Elisabeth; Thiry, Yves

    2013-04-01

    Chlorine-36 is a cosmogenic nuclide mainly produced in the atmosphere by interactions between energetic particles originating from the cosmic radiations and 40Ar. Because of its long half-life (T1-2 = 3.01 105 yr) and its high mobility, chlorine-36 is a critical radionuclide concerning radioactive waste repository sites. Moreover, it has been shown that inorganic chlorine could be enriched along the trophic chain due to its high solubility and bioavailability (Ashworth and Shaw, 2006). Additionally, many studies during the last decades have established that due to chlorination process, organic chlorine may account for a large proportion of the total soil chlorine pool (more than 80 % in surface soils of temperate ecosystems. Redon et al., 2012). The aim of this study is thus to measure chlorine-36 in all the compartments of the biogeochemical cycle, to better understand its recycling in the biosphere. The study site is the experimental beech forest site of the Andra long-term monitoring and testing system (OPE*). It is located at Montiers-sur-Saulx, North-East of France and is associated to the future radioactive waste repository site of Bure. Since March 2012, rainwater above (rainfall collected from a 45 m high tower built on purpose) and below (throughfall and stemflow) the canopy, has been collected monthly, as well as soil solutions (gravitational and bound waters) at four depths (0, 10, 30, 60 cm deep). Chlorine-36 and chlorine have been measured in the rainfall samples between March and July 2012 and in water solutions collected from all compartments of the biosphere using isotope dilution mass spectrometry at the french AMS national facility ASTER located at CEREGE. The results yielded from the rainfall samples allow to study the temporal fluctuations of chlorine-36 in the atmosphere, which represents the main inflow of chlorine-36 in its biogeochemical cycle. The first results indicate a flow increase during the late spring-early summer. Santos et al

  12. The impact of the absence of aliphatic glucosinolates on water transport under salt stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Mcarmen eMartinez-Ballesta

    2015-07-01

    Full Text Available Members of the Brassicaceae are known for their contents of nutrients and health-promoting phytochemicals, including glucosinolatesExposure to salinity increases the levels of several of these compounds, but their role in abiotic stress response is unclear. The effect of aliphatic glucosinolates on plant water balance and growth under salt stress, involving aquaporins, was investigated by means of Arabidopsis thaliana mutants impaired in aliphatic glucosinolate biosynthesis, which is controlled by two transcription factors: Myb28 and Myb29. The double mutant myb28myb29, completely lacking aliphatic glucosinolates, was compared to wild type Col-0 (WT and the single mutant myb28. A greater reduction in the hydraulic conductivity of myb28myb29 was observed under salt stress, when compared to the WT and myb28; this correlated with the abundance of both PIP1 and PIP2 aquaporin subfamilies. Also, changes in root architecture in response to salinity were genotype dependent. Treatment with NaCl altered glucosinolates biosynthesis in a similar way in WT and the single mutant and differently in the double mutant. The results indicate that short-chain aliphatic glucosinolates may contribute to water saving under salt stress

  13. Ecotoxicologically based environmental risk limits for several volatile aliphatic hydrocarbons

    NARCIS (Netherlands)

    Jong FMW de; Posthuma-Doodeman CJAM; Verbruggen EMJ; SEC

    2007-01-01

    This report describes ecotoxicological environmental risk limits derived for a number of volatile aliphatic hydrocarbons. On the basis of evaluated literature, the National Institute for Public Health and the Environment (RIVM) proposes ecotoxicological environmental risk limits for these compounds

  14. Aliphatic nitro alcohols. Synthesis, chemical transformations and applications

    Energy Technology Data Exchange (ETDEWEB)

    Shvekhgeimer, Mai-Genrikh A [A.N. Kosygin Moscow State Textile Academy, Moscow (Russian Federation)

    1998-01-31

    The data on the synthesis, chemical transformations and practical use of aliphatic nitro alcohols published over the last 25 years are described systematically and analysed. The bibliography includes 316 references.

  15. Gold-Catalyzed Regioselective Dimerization of Aliphatic Terminal Alkynes.

    Science.gov (United States)

    Sun, Sheng; Kroll, Julien; Luo, Yingdong; Zhang, Liming

    2012-01-01

    A gold-catalyzed regioselective homodimerization of aliphatic terminal alkynes is described. Bulky and less Lewis acidic tBuXPhosAuNTf(2) is the preferred catalyst, and the additive, anhydrous NaOAc, substantially facilitates the reaction.

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

    Science.gov (United States)

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

    2011-01-14

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

  17. Decomposition mechanisms of trinitroalkyl compounds: a theoretical study from aliphatic to aromatic nitro compounds.

    Science.gov (United States)

    Fayet, Guillaume; Rotureau, Patricia; Minisini, Benoit

    2014-04-14

    The chemical mechanisms involved in the decomposition of trinitroethyl compounds were studied for both aliphatic and aromatic derivatives using density functional theory calculations. At first, in the case of 1,1,1-trinitrobutane, used as a reference molecule, two primary channels were highlighted among the five investigated ones: the breaking of the C-N bond and the HONO elimination. Then, the influence of various structural parameters was studied for these two reactions by changing the length of the carbon chain, adding substituents or double bonds along the carbon chain. If some slight changes in activation energies were observed for most of these features, no modification of the competition between the two investigated reactions was highlighted and the breaking of the C-N bond remained the favoured mechanism. At last, the reactions involving the trinitroalkyl fragments were highlighted to be more competitive than reactions involving nitro groups linked to aromatic cycles in two aromatic systems (4-(1,1,1-trinitrobutyl)-nitrobenzene and 2-(1,1,1-trinitrobutyl)-nitrobenzene). This showed that aromatic nitro compounds with trinitroalkyl derivatives decompose from their alkyl part and may be considered more likely as aliphatic than as aromatic regarding the initiation of their decomposition process.

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

    Science.gov (United States)

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

    2009-04-01

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

  19. A comparison of chlorinated organic material produced by chlorine and chlorine dioxide bleaching

    Energy Technology Data Exchange (ETDEWEB)

    McKaque, A.B.; Reeve, D.W. [Univ. of Toronto (Canada)

    1995-12-31

    Chlorine and chlorine dioxide react differently with pulp during bleaching and produce different types of organic by-products. The main differences are the large reduction in the amount of AOX (adsorbable organic halogen) in the effluent and EOX (extractable organic halogen) in the pulp. This talk reviews the differences in the amounts and types of chlorinated organic by-products produced by the two different bleaching agents.

  20. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    Science.gov (United States)

    Taylor, Robert H.; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains were more resistant to chlorine than were cells of the more rapidly growing strains. Water-grown cells were 10-fold more resistant than medium-grown cells. Disinfectant resistance may be one factor promoting the persistence of M. avium in drinking water. PMID:10742264

  1. In vitro antibacterial activity of some aliphatic aldehydes from Olea europaea L.

    Science.gov (United States)

    Bisignano, G; Laganà, M G; Trombetta, D; Arena, S; Nostro, A; Uccella, N; Mazzanti, G; Saija, A

    2001-04-20

    In the present paper we report the 'in vitro' activity of eight aliphatic long-chain aldehydes from olive flavor (hexanal, nonanal, (E)-2-hexenal, (E)-2-eptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal and (E,E)-2,4-decadienal) against a number of standard and freshly isolated bacterial strains that may be causal agents of human intestinal and respiratory tract infections. The saturated aldehydes characterized in the present study do not exhibit significant antibacterial activity, while the alpha,beta-unsaturated aldehydes have a broad antimicrobial spectrum and show similar activity against Gram-positive and Gram-negative microorganisms. The effectiveness of the aldehydes under investigation seems to depend not only on the presence of the alpha,beta-double bond, but also on the chain length from the enal group and on the microorganism tested.

  2. Occurrence of selected aliphatic amines in source water of major cities in China

    Institute of Scientific and Technical Information of China (English)

    Haifeng Zhang; Shuoyi Ren; Jianwei Yu; Min Yang

    2012-01-01

    The formation of toxic nitrogenous disinfection byproducts (N-DBPs),such as nitrosamines,halonitromethanes and haloacetonitriles,from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health.This study revealed the occurrence of 17 aliphatic amines,some of which have been confirmed to be the precursors of N-DBPs,in source water across China.A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples.In total,37 source water samples from the capital cities of 20 provinces were collected for the survey.Among the 17 amines,14 were detected with an average frequency of detection of 36%.The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine (100%,24.82 μg/L),methylamine (78%,0.92 μg/L),N-methylethylamine (70%,8.84 μg/L),propylamine (59%,10.69 μg/L),diethylamine (54%,3.76 μg/L),N-methylbutylamine (35%,3.07 μg/L),N-ethylpropylamine (35%,0.52 μg/L),and piperidine (32%,2.35 μg/L).This is the first large scale survey of the aliphatic amines occurrence in source water in the world.The wide presence of nitrosamine precursors like dimethylamine,N-methylethylamine and diethylamine,and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.

  3. Inactivation of Chironomid Larvae with Chlorine Dioxide and Chlorine

    Institute of Scientific and Technical Information of China (English)

    SUN Xin-bin; CUI Fu-yi

    2008-01-01

    Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process.The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some boundary values in practice were determined under conditions of various oxidant dosage,organic precursor concentration and pH value.In addition,removal effect of differmt pre-oxidation combined with coagulation process on Chironomid larvae in law water was evaluated.It was found that chlorine dioxide possessed better inactivation effect than chlorine.Complete inactivation of Chironomid larvae in raw water was resulted by 1.5mg/L of chlorine dioxide with 30min of contact time. Additionally,the ocgallic precursor concentration,pH value had little influence on the inactivation effect.The coagulation jar test showed that Chironomid larvae in the raw water could be completely ronxwed by chlorine dioxide pre-oxidation in combination with the omgulation process at chlorine dioxide dosage of 0.8 mg/L.

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

    Science.gov (United States)

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

    2014-06-01

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

  5. Molecular polarizability effect index and boiling point of aliphatic aldehydes and alkanones%分子极化效应指数与脂肪族醛酮的沸点

    Institute of Scientific and Technical Information of China (English)

    张秀利; 汪勇先; 林英武; 李俊玲

    2003-01-01

    Based on the molecular polarizabihty effect index,a formula of three parameters was proposed to calculate the boiling point of aliphatic aldehydes and alkanones. ln(820.5 - Tb) = 6.38330- 1.37357 × 10-1 Nc + 5.39350ΔEPI + 8.02603 × 10-2N Where the Nc is the effective length of carbon chain of alkyl group in the aliphatic aldehydes and alkanones. The ΔPEI is the polarizability effect index difference between the corresponding branched and normal alkyl isomer containing the same carbon atom number, which expressed the effcet of carbonyl group on the boiling point of aliphatic aldehydes and alkanones. N is the carbon numbers of aliphatic aldehydes and alkanones.

  6. Composition and sources of aliphatic lipids and sterols in sediments of a tropical island, southern South China Sea: preliminary assessment.

    Science.gov (United States)

    Mohd Tahir, N; Pang, S Y; Abdullah, N A; Suratman, S

    2013-12-01

    Near-shore surface sediment was collected from five stations off Redang Island located on the eastern coast of Peninsular Malaysia. Freeze-dried sediments were Soxhlet extracted and then fractionated using column chromatography into aliphatic and polar fractions. Determination of these fractions was carried out using gas chromatography mass spectrometry. The concentration of total resolved aliphatic hydrocarbons in sediments ranged from 157 to 308 ng/g. The distribution of aliphatic fraction showed the presence of n-alkanes ranging from nC15 to nC33 with a minor odd-to-even predominance exhibiting carbon maximum, depending on station, at nC17, nC26, nC29 or nC31. Calculation of Carbon Preference Index (CPI) for CPI(15-33) gave values ranging from 1.09 to 1.46. n-Alkanol in all sediment exhibits even-to-odd carbon predominance ranging from nC16 to nC28 and maximising at nC22. n-Fatty acids distribution ranged from nC14 to nC24 with a dominant maximum at nC16 and exhibiting high values of short chain fatty acids (≤nC20) to long chain fatty acids (>nC20) ratios. Unsaturated fatty acids, particularly nC16:1 and nC18:1 is also ubiquitous in all samples. Cholesterol is the most abundant compound amongst the sterol group ranging from 42.8 to 62.6% of the total sterols. β-Sitosterol, brassicasterol and stigmasterol, are also present but of relatively lower amount. These observations suggest that the aliphatic lipids and sterols in the study area originate, mainly, from biogenic sources of marine microbial with minor contribution from epiticular waxes of terrestrial plants.

  7. Enzymatic chlorination and bromination.

    Science.gov (United States)

    van Pée, Karl-Heinz

    2012-01-01

    Our knowledge about the enzymes catalyzing the incorporation of halide ions during the biosynthesis of halometabolites has increased tremendously during the last 15 years. Between 1960 and 1995, haloperoxidases were the only halogenating enzymes known. However, absolute proof for the connection of haloperoxidases to the biosynthesis of halometabolites is still missing. In 1997, FADH(2)-dependent halogenases were identified as the type of halogenating enzymes responsible for the incorporation of chloride and bromide atoms into aromatic and aliphatic compounds activated for electrophilic attack. FADH(2)-dependent halogenases are two-component systems consisting of a flavin reductase providing the FADH(2) required by the halogenase. Elucidation of the three-dimensional structure of FADH(2)-dependent halogenases led to the understanding of the reaction mechanism, which involves the formation of hypohalous acids. Unactivated carbon atoms were found to be halogenated by nonheme iron, α-ketoglutarate- and O(2)-dependent halogenases. The reaction mechanism of this type of halogenase was shown to involve the formation of a substrate radical. These two types of halogenating enzymes, together with the much less common fluorinases, are the major types of halogenating enzymes. However, the existence of other types of halogenating enzymes, yet not detected, cannot be completely ruled out. Here, we describe the detection, purification, characterization, and reaction mechanisms of flavin-dependent halogenases and of nonheme iron, α-ketoglutarate- and O(2)-dependent halogenases.

  8. Simulating stable carbon and chlorine isotope ratios in dissolved chlorinated groundwater pollutants with BIOCHLOR-ISO

    Science.gov (United States)

    Höhener, Patrick

    2016-12-01

    BIOCHLOR is a well-known simple tool for evaluating the transport of dissolved chlorinated solvents in groundwater, ideal for rapid screening and teaching. This work extends the BIOCHLOR model for the calculation of stable isotope ratios of carbon and chlorine isotopes in chloroethenes. An exact solution for the three-dimensional reactive transport of a chain of degrading compounds including sorption is provided in a spreadsheet and applied for modeling the transport of individual isotopes 12C, 13C, 35Cl, 37Cl from a constant source. The model can consider secondary isotope effects that can occur in the breaking of Csbnd Cl bonds. The model is correctly reproducing results for δ13C and δ37Cl modeled by a previously published 1-D numerical model without secondary isotope effects, and is also reproducing results from a microcosm experiment with secondary chlorine isotope effects. Two applications of the model using field data from literature are further given and discussed. The new BIOCHLOR-ISO model is distributed as a spreadsheet (MS EXCEL) along with this publication.

  9. Silver-Catalyzed Decarboxylative Azidation of Aliphatic Carboxylic Acids.

    Science.gov (United States)

    Zhu, Yuchao; Li, Xinyao; Wang, Xiaoyang; Huang, Xiaoqiang; Shen, Tao; Zhang, Yiqun; Sun, Xiang; Zou, Miancheng; Song, Song; Jiao, Ning

    2015-10-02

    The catalytic decarboxylative nitrogenation of aliphatic carboxylic acids for the synthesis of alkyl azides is reported. A series of tertiary, secondary, and primary organoazides were prepared from easily available aliphatic carboxylic acids by using K2S2O8 as the oxidant and PhSO2N3 as the nitrogen source. The EPR experiment sufficiently proved that an alkyl radical process was generated in the process, and DFT calculations further supported the SET process followed by a stepwise SH2 reaction to afford azide product.

  10. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    Energy Technology Data Exchange (ETDEWEB)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F., E-mail: luizfsjr@iq.usp.br [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2013-09-15

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  11. Gaseous, chlorine-free chlorine dioxide for drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, G. [Miami Univ., Oxford, OH (United States); Rosenblatt, A. [CDG Technology Inc., New York, NY (United States)

    1996-11-01

    The benefits of applying chlorine dioxide (ClO{sub 2}) for the oxidative treatment of drinking water are well established. Chlorine dioxide treated finished water typically has substantially lower trihalomethane (THM) levels because ClO{sub 2} will not form chlorinated organic species as a by-product of disinfection. The THMs that are formed are probably due to chlorine from the generator or chlorine used to maintain a post-disinfection residual. An emerging regulatory issue concerning the formation of disinfection by-products (DBPs) is causing the water industry to set standards for the generation and delivery of ClO{sub 2}. The Federal Register (11 February 1994) contains language developed to limit the production of the unwanted inorganic by-products chlorite (ClO{sub 2}{sup -}), chlorate (ClO{sub 3}{sup -}), and bromate (BrO{sub 3}{sup -}) ions by requiring utilities to maintain high (95%) generation efficiencies and by limiting the amount of excess Cl{sub 2} that can be used during the generation process. The efficiency and excess Cl{sub 2} regulations may be problematic for utilities that over-chlorinate to attain chlorine dioxide high yields. Many utilities will have to decide either to reduce the amount of Cl{sub 2} used to react with sodium chlorite (NaClO{sub 2}), thereby increasing the ClO{sub 2}{sup -} residual in finished water, or over-chlorinate to increase yields and surpass the excess Cl{sub 2} limits.

  12. Application of flow-injection potentiometric system for determination of total concentration of aliphatic carboxylic acids.

    Science.gov (United States)

    Mroczkiewicz, Monika; Górski, Łukasz; Zamojska-Jaroszewicz, Anna; Szewczyk, Krzysztof W; Malinowska, Elżbieta

    2011-09-30

    In this work, flow-injection system with potentiometric detection was tested for determination of total carboxylic acid concentration. Detection part of the examined system consists of ion-selective electrodes (ISEs) with polymer membranes of different compositions. First electrode is based on Zr(IV)-tetraphenylporphyrin as ionophore selective towards carboxylic acid anions, the membrane of second one contains only liphophilic anion exchanger - tridodecylmethylammonium chloride. Final response of the system is a result of combination of EMF signals from both electrodes. Combination of two detectors enables significant decrease of differences between potentiometric signals induced by mixtures of studied anions of various concentrations as compared to results obtained only with metalloporphyrin-based ISE. The use of anion-exchanger based detector allows for elimination of the influence of aliphatic carboxylic acids lipophilicity. Proposed potentiometric flow-injection system was employed for determination of short-chain aliphatic carboxylic acids (so-called VFA - volatile fatty acids) in samples originating from an anaerobic digester. Results obtained for these relatively complicated samples are in good agreement with results obtained with the use of reference colorimetric method. Linear response towards carboxylic acids was observed in the concentration range of 10(-4) to 10(-2)mold m(-3), with the slopes in the range of -110 to -150 mV dec(-1) (for acetate(-) and butyrate(-), respectively). System enables for determination of about 6 samples per hour. Life time of ISEs average about 2 months.

  13. Chiroptical study of α-aliphatic amino acid films in the vacuum ultraviolet region.

    Science.gov (United States)

    Tanaka, Masahito; Yagi-Watanabe, Kazutoshi; Kaneko, Fusae; Nakagawa, Kazumichi

    2010-11-11

    A series of natural circular dichroism (CD) and absorption spectra for films of α-aliphatic amino acids--such as alanine, aminobutyric acid, norvaline, norleucine, valine, leucine, and isoleucine--in the vacuum ultraviolet (VUV) region were observed with the absolute values of optical constants at the undulator-based CD beamline TERAS BL5. Preliminary predictions of some CD spectra were also performed, based on quantum-chemical calculations using the crystal structure. Although the absorption spectra show similar features to each other, significant differences between the CD spectra were found, especially in the 7-8 eV region. The CD spectra of aliphatic amino acids with branched alkyl groups in the side-chain--such as valine, leucine, and isoleucine--exhibit strong negative CD peaks in this energy region. In contrast, the corresponding CD peaks were weak or absent in the spectra of amino acids with straight alkyl groups. Our simple calculation, and the absorption spectra of alkanes, suggest that this difference partly originates from the contribution of the alkyl group. Clear discrepancies between the CD spectra of these amino acids in solutions and those in the solid state were also observed; this is probably caused by the different molecular structures in each state. Our results clearly indicated that CD spectra in the VUV region were very sensitive to the conformations of chiral molecules.

  14. Identification of Some AOX Compounds Formed in Wool Chlorination Using Model Chemicals

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; HE Jin-xin; DAJ Jin-jin

    2002-01-01

    The AOX (adsorbable organic halogens) problem in wool shrinkproofing effluents has attracted more attention in recent years. The probable origins and structures of AOX compounds were proved by the reaction of DCCA with the model substances of different amino acid residues.The GC-MS results indicated that available chlorine could chlorinate the side chain of tyrosine, histidine and trypotophan and generate AOX load in the effluent.

  15. Improved method generates more chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, R.W.; Kosinski, A.J.; Baker, R.J.

    1980-10-01

    The addition of acid can greatly improve the chlorine-chlorite process and enhance the use of chlorine dioxide as an alternative to chlorine for disinfection. The process is economical for use in taste and odor control, and for manganese, oxidation. The maximum yield is obtained using no excess chlorine, and the amount of unreacted sodium chlorite and chlorine in the product stream is reduced. (1 diagram, 4 graphs, 9 references)

  16. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  17. Ultrasound-assisted synthesis of aliphatic acid esters at room temperature.

    Science.gov (United States)

    Hobuss, Cristiane B; Venzke, Dalila; Pacheco, Bruna S; Souza, Alexander O; Santos, Marco A Z; Moura, Sidnei; Quina, Frank H; Fiametti, Karina G; Vladimir Oliveira, J; Pereira, Claudio M P

    2012-05-01

    This work describes the ultrasound-assisted synthesis of saturated aliphatic esters from synthetic aliphatic acids and either methanol or ethanol. The products were isolated in good yields after short reaction times under mild conditions.

  18. Polymeric Amines by chemical modifications of alternating aliphatic polyketones

    NARCIS (Netherlands)

    Zhang, Youchun; Broekhuis, A. A.; Stuart, Marc C. A.; Picchioni, F.

    2008-01-01

    Alternating, aliphatic polyketones were chemically modified by using di-amines to obtain polymeric products having pendant amino groups. The used reaction, Paal-Knorr, involves the formation of pyrrole rings along the polyketone backbone. The corresponding kinetics and final conversions are clearly

  19. The aliphatic counterpart of PET, PPT and PBT aromatic polyesters: effect of the molecular structure on thermo-mechanical properties

    Directory of Open Access Journals (Sweden)

    Morgane Albanese

    2016-02-01

    Full Text Available The aliphatic counterparts of the most used aromatic polyesters (PET, PPT, and PBT have been synthesized by a two-stage polycondensation process, starting from dimethyl 1,4-cyclohexane dicarboxylate and different diols. The fully aliphatic polyesters are characterized by two cis/trans isomeric ratios (50 and 90 mol% of the 1,4-cycloaliphatic rings. According to the cis/trans content, the properties of the materials notably change. Indeed, polymers rich in trans isomer are semicrystalline, whereas polymers with low trans content are fully amorphous, due to the presence of kinks along the chain. Trans isomer is characterized by higher rigidity than the cis one and the corresponding polymers have high glass transition temperatures. Moreover, the length of the methylene sequences in the diol has a notable influence on the final thermal and mechanical properties. Therefore, tunable properties can be easily obtained. This characteristic, in association with good mechanical performances, potential sustainability of the monomers and biodegradability, makes these aliphatic polyesters an interesting class of polyesters for some specific applications.

  20. Surface complex formation between aliphatic nitrile molecules and transition metal atoms for thermally stable lithium-ion batteries.

    Science.gov (United States)

    Kim, Young-Soo; Lee, Hochun; Song, Hyun-Kon

    2014-06-11

    Non-flammability of electrolyte and tolerance of cells against thermal abuse should be guaranteed for widespread applications of lithium-ion batteries (LIBs). As a strategy to improve thermal stability of LIBs, here, we report on nitrile-based molecular coverage on surface of cathode active materials to block or suppress thermally accelerated side reactions between electrode and electrolyte. Two different series of aliphatic nitriles were introduced as an additive into a carbonate-based electrolyte: di-nitriles (CN-[CH2]n-CN with n = 2, 5, and 10) and mono-nitriles (CH3-[CH2]m-CN with m = 2, 5, and 10). On the basis of the strong interaction between the electronegativity of nitrile functional groups and the electropositivity of cobalt in LiCoO2 cathode, aliphatic mono- and di-nitrile molecules improved the thermal stability of lithium ion cells by efficiently protecting the surface of LiCoO2. Three factors, the surface coverage θ, the steric hindrance of aliphatic moiety within nitrile molecule, and the chain polarity, mainly affect thermal tolerance as well as cell performances at elevated temperature.

  1. Biosynthetic pathway of aliphatic formates via a Baeyer–Villiger oxidation in mechanism present in astigmatid mites

    Science.gov (United States)

    Shimizu, Nobuhiro; Sakata, Daisuke; Schmelz, Eric A.; Mori, Naoki; Kuwahara, Yasumasa

    2017-01-01

    Astigmatid mites depend on bioactive glandular secretions, pheromones, and defensive agents to mediate intra- and interspecies interactions. Aliphatic formates, such as (Z,Z)-8,11-heptadecadienyl formate (8,11-F17) and (Z)-8-heptadecenyl formate (8-F17), are rarely encountered natural products that are abundant in Sancassania sp. Sasagawa (Acari: Acaridae) mite secretions. Linoleic acid and oleic acid are predicted as key intermediates in the synthesis of the closely related aliphatic formates. To gain insight in this biosynthetic pathway, acarid mite feeding experiments were conducted using 13C-labeled precursors to precisely track incorporation. Analyses using 13C NMR spectroscopy demonstrated that the 13C-labeling pattern of the precursors was detectable on formates in exocrine secretions and likewise on fatty acids in total lipid pools. Curiously, the results demonstrated that the formates were biosynthesized without the dehomologation of corresponding fatty acids. Careful examination of the mass spectra from labeling experiments revealed that the carbonyl carbon of the formates is originally derived from the C-1 position of the fatty acids. Consistent with a Baeyer–Villiger oxidation reaction, labeling studies support the insertion of an oxygen atom between the carbonyl group and carbon chain. Empirical data support the existence of a Baeyer–Villiger monooxygenase responsible for the catalyzation of the Baeyer–Villiger oxidation. The predicted existence of a Baeyer–Villiger monooxygenase capable of converting aliphatic aldehydes to formates represents an exciting opportunity to expand the enzymatic toolbox available for controlled biochemical synthesis. PMID:28223501

  2. [Aliphatic characteristics of the fractions isolated from the soil fulvic acid using XAD-8 column].

    Science.gov (United States)

    Liu, Ben-ding; Li, Xia; Dai, Jing-yu

    2007-10-01

    In order to truly understand the character and structure of fulvic acid, which contains many substances, the authors isolated fulvic acid detailedly according to its definite character and its characteristic of similar structure. Fulvic acid with H+ can be adsorbed by the XAD-8 column balanced by the usual buffer(pH 2). The hydrophilic fraction in fulvic acid can be divided into three groups using the buffer with various pH (4.8, 7.0 and 11.0), while the hydrophobic fraction can be classified into two groups by the distilled water and alcohol separately. For FTIR (Fourier transform infrared) and NMR (nuclear magnetic resonance) spectroscopy analysis, three paddy soils were used. It may be concluded that the content of oxygen and carboxyl group dissolved at low pH is more than that dissolved in the water and alcohol, but the content of aliphatic fraction is less and has short side chain.

  3. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Science.gov (United States)

    2010-07-01

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

  4. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyaziridinyl ester of an aliphatic... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  5. Cleaning without chlorinated solvents

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.M.; Simandl, R.F.

    1994-12-31

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

  6. 脂肪族水性聚氨酯涂料的研制%Development of Waterborne Aliphatic Polyurethane Coatings

    Institute of Scientific and Technical Information of China (English)

    许戈文; 熊潜生; 等

    2001-01-01

    A waterborne aliphatic polyurethane coatings was prepared by epoxy resin modified polyurethane and IPDI instead of TDI. The in fluences ofreaction temperature, catalyst, NCO content and chain extender etc. on the paint property were discussed.%采用环氧树脂改性聚氨酯,异佛尔酮二异氰酸酯代替甲苯二异氰酸酯合成出耐候性好的水性聚氨酯树脂。讨论了反应温度、催化剂、NCO含量及扩链剂等对涂料性能的影响。

  7. Structure and morphology of thin films of linear aliphatic polyesters prepared by spin-coating.

    Science.gov (United States)

    Hernández, J J; Rueda, D R; García-Gutiérrez, M C; Nogales, A; Ezquerra, T A; Soccio, M; Lotti, N; Munari, A

    2010-07-06

    Thin films, with thicknesses from 10 to 400 nm of linear aliphatic polyesters (X, Y), based on propylenediol (X = 3) and on dicarboxylic acid of different chain length (Y = 2, 3, and 4 CH(2) units) were prepared by spin coating of CHCl(3) polymer solutions with different polymer concentrations. Morphology and structure of the spin coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence X-ray scattering techniques at small, (GISAXS) and wide angles (GIWAXS). AFM revealed a strong dewetting for all three polymers for coatings thinner than 100 nm. The polymer films are clearly semicrystalline for thicknesses higher than 50 nm. GIWAXS of the thicker films revealed their oriented crystalline nature. An edge-on-lamellae morphology is clearly shown by the AFM-phase images even for relatively thin films. SAXS with the beam parallel to the sample plane also support the presence of lamellae perpendicular to the substrate. The use of a mu-beam helped to interpret the GIWAXS patterns and allowed to obtain oriented WAXS patterns from melt solidified filaments. Thus, a crystal chain packing is proposed for the three polymers and consequently the indexing of the observed reflections. Accordingly, the polymer chains lie parallel to the substrate being the bc plane of the monoclinic crystal unit cell parallel to the substrate.

  8. Syntheses of aliphatic polycarbonates from 2'-deoxyribonucleosides.

    Science.gov (United States)

    Suzuki, Masato; Sekido, Toyokazu; Matsuoka, Shin-ichi; Takagi, Koji

    2011-05-01

    Poly(2'-deoxyadenosine) and poly(thymidine) constructed of carbonate linkages were synthesized by polycondensation between silyl ether and carbonylimidazolide at the 3'- and 5'-positions of the 2'-deoxyribonucleoside monomers. The N-benzoyl-2'-deoxyadenosine monomer afforded the corresponding polycarbonate together with the cyclic oligomers. However, the deprotection of the N-benzoyl group resulted in the scission of the polymer main chain. Thus, the N-unprotected 2'-deoxyadenosine monomers were examined for polycondensation. However, there was involved the undesired reaction between the adenine amino group and the carbonylimidazolide to form the carbamate linkage. In order to exclude this unfavorable reaction, dynamic protection was employed. Strong hydrogen bonding was used in place of the usual covalent bonding for reducing the nucleophilicity of the adenine amino group. Herein, 3',5'-O-diacylthymidines that form the complementary hydrogen bonding with the adenine amino group were added to the polymerization system of the N-unprotected 2'-deoxyadenosine monomer. Consequently, although the oligomers (M(n) = 1000-1500) were produced, the contents of the carbamate group were greatly reduced. The dynamic protection reagents were easily and quantitatively recovered as the MeOH soluble parts from the polymerization mixtures. In the polycondensation of the thymidine monomer, there tended to be involved another unfavorable reaction of carbonate exchange, which consequently formed the irregular carbonate linkages at not only the 3'-5' but also the 3'-3' and 5'-5' positions. Employing the well-designed monomer suppressed the carbonate exchange reaction to produce poly(thymidine) with the almost regular 3'-5'carbonate linkages.

  9. Theoretical structural study on the adsorption properties of aliphatic aldehydes on ZnO nanoclusters and graphene-like nanosheets systems

    Science.gov (United States)

    Tayebee, R.; Zamand, N.; Hosseini-nasr, A.; Kargar Razi, M.

    2014-05-01

    The structure optimizations for some aliphatic aldehydes adsorbed on ZnO nanoclusters, and graphene-like nanosheets were carried out using the B3LYP/LanL2DZ calculations and the adsorption energies were calculated. It was considered that adsorption of the examined aldehydes on the ZnO nanoclusters and graphene-like nanosheets occurred through carbonyl oxygens of aldehyde molecules with the surface Zn2+ ions of the central ring. Aldehydes with the general formula of R-COH (R denotes a branched or linear aliphatic chain with maximum of three carbon atoms) were considered. Also, Effects of chain length were investigated on the orientation of the aldehyde molecules with respect to the nanosheet and nanocluster surfaces. Findings revealed that the adsorption energy was decreased with enhancing chain length. However, the most negative adsorption energy was obtained for iso-butyraldehyde, as a branched aldehyde. Interaction of the aldehyde molecules with the surfaces of nanosheets were analyzed by means of DOS analysis and Bader's method. We hope the obtained results be helpful in identifying the mechanism of cyclotrimerization of aliphatic aldehydes on the surface of zinc oxide nanoparticles.

  10. 脂肪族聚碳酸酯及其在医学中的应用%Progress of Aliphatic Polycarbonates and their Applications in the Biomedical Field

    Institute of Scientific and Technical Information of China (English)

    周瑜; 刘芝兰; 陈红祥

    2011-01-01

    During the past decade,aliphatic polycarbonates have been widely studied and used in the biomedical field,because they are biocompatible,biodegradable and able to functionalization.In this article,combining with the authors' work and referring to the research status about biodegradable aliphatic polycarbonates at home and abroad,aliphatic polycarbonates were sorted according to the structure of polymer chains and also introduced briefly.Their synthetic methods and applications in the biomedical field were reviewed.In addition,the future development of aliphatic polycarbonates was also put forward.%脂肪族聚碳酸酯具有优良的生物降解性、生物相容性和可功能化性等特点,近十几年来在生物医学领域得到了迅速发展。结合本实验室对生物可降解脂肪族聚碳酸酯的研究工作以及国内外研究现状,根据高分子链的几何形状对脂肪族聚碳酸酯进行了分类介绍,综述了它们的合成方法及其在生物医学领域中的应用,同时展望了脂肪族聚碳酸酯的未来发展趋势。

  11. Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

    Science.gov (United States)

    Smith, G. B.

    1996-01-01

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

  12. Determination of aliphatic hydrocarbons in the alga Himanthalia elongata.

    Science.gov (United States)

    Punín Crespo, M O; Lage Yusty, M A

    2004-02-01

    The algae considered new foods according to Regulation CE 258/97 need a guarantee of their healthfulness before being in the European market. In this work ten samples of the brown alga Himanthalia elongata have been analyzed with the aim of verifying the absence of aliphatic hydrocarbons, due to the ability of the macroalgae to capture lipophilic organic compounds of the marine water coming from accidental or continuous leaks of raw oil and refined products, which happen each year with the growth of the industrialization and the demand of energy. The fat of the samples were Soxhlet extracted using hexane:dichloromethane (1:1) for 7h. The organic fractions were purified using silica microcolumns. The identification and quantification of the aliphatic hydrocarbons have been carried out using gas chromatography (GC) with flame ionization detector (FID). The total hydrocarbon content was between 14.8 and 40.2 microg g(-1) dry weight.

  13. Aliphatics hydrocarbon content in surface sediment from Jakarta Bay, Indonesia

    Science.gov (United States)

    YAzis, M.; Asia, L.; Piram, A.; Doumenq, P.; Syakti, A. D.

    2016-02-01

    Sedimentary aliphatic hydrocarbons content have been studied quantitatively and qualitatively using GC/MS method in eight coastal stations located in the Jakarta Bay, North of Jakarta, Indonesia. The total concentrations n-alkanes have ranged from 480 μg.kg-1to 1,935 μg.kg-1sediment dry weight. Several ratios (e.g. CPI24-32, NAR, TAR, Pr/Phy, n-C17/Pr, n- C18/Phyt,n-C29/n-C17, Ʃn-alkanes/n-C16LMW/HMW, Paq and TMD) were used to evaluate the possible sources of terrestrial-marine inputs of these hydrocarbons in the sediments. The various origins of aliphatic hydrocarbons were generally biogenic, including both terrigenous and marine, with an anthropogenic pyrolytic contribution (petrogenic and biogenic combustion). Two stations (G,H) were thehighest concentration and had potential risk to environment

  14. Colorectal cancers and chlorinated water

    Institute of Scientific and Technical Information of China (English)

    Ahmed Mahmoud El-Tawil

    2016-01-01

    Published reports have revealed increased risk of colorectal cancers in people exposed to chlorinated drinking water or chemical derivatives of chlorination. Oestrogen plays a dual positive functions for diminishing the possibilities of such risk by reducing the entrance, and increasing the excretion, of these chemicals. In addition, there are supplementary measures that could be employed in order to reduce this risk further, such as boiling the drinking water, revising the standard concentrations of calcium, magnesium and iron in the public drinking water and prescribing oestrogen in susceptible individuals. Hypo-methylation of genomic DNA could be used as a biological marker for screening for the potential development of colorectal cancers.

  15. Japodic Acid, A Novel Aliphatic Acid from Jatropha podagrica Hook

    OpenAIRE

    Aiyelaagbe, Olapeju O.; Gloer, James B.

    2008-01-01

    A new aliphatic acid named japodic acid (1) with a gem-dimethyl cyclopropane ring has been isolated from the roots of Jatropha podagrica. Its structure was established by 1D and 2D NMR and mass spectrometric data. Two other known compounds, erythrinasinate (2) and fraxidin (3) were also isolated from this plant for the first time. Japodic acid showed mild insect growth inhibition activity against Helicoverpa zea (37% growth reduction at 100 ppm). Fraxidin and erythrinasinate exhibited antibac...

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

    Science.gov (United States)

    Braddock, J.F.

    1999-01-01

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

  17. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    OpenAIRE

    Korich, D. G.; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactiv...

  18. Disinfectants: Chlorine and chlorine dioxide. (Latest citations from the Life Sciences Collection database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    The bibliography contains citations concerning the antimicrobial properties of chlorine and chlorine dioxide. The use of chlorine for the inactivation of viruses, bacteria, and fungi in wastewater treatment plants is discussed, including the mode of action and factors influencing inactivation. The use of chlorine dioxide as an alternative to chlorine disinfection in swimming pools and water supplies, and possible adverse effects are also discussed. (Contains a minimum of 157 citations and includes a subject term index and title list.)

  19. Mortality of Bemisia tabaci biotype B (sternorrhyncha: aleyrodidae adults by aliphatic and aromatic synthetic sucrose esters

    Directory of Open Access Journals (Sweden)

    Mariangela Alves

    2008-12-01

    Full Text Available The B-strain of Bemisia tabaci Gennadius is a key pest of several crops and chemical control is the main control method used by growers, although reduction in efficacy due to insecticide resistance has already been reported. The aim of this work was to investigate the insecticidal effect of an array of synthetic sucrose esters with the aliphatic and aromatic groups on whitefly adults. Sucrose butyrate, caprate, octanoate, palmitate, oleate, octaacetate, phthalate, benzoate, and sucrose diacetate hexaisobutyrate were tested. The solutions were prepared and applied on the adults caught on yellow sticky traps using the Potter spray tower. Long-chains sucrose aliphatic esters were more effective against the silverleaf whiteflies and the highest mortality was obtained with sucrose oleate and sucrose octanoate. Since these compounds were tensoactive, sodium dodecylsulphate was also tested for the comparison but no effect was observed. Sucrose butyrate and other aliphatic and aromatic sucrose polyesters showed negligible effect on the silverleaf whiteflies.O biótipo B de B. tabaci Gennadius tem se destacado como uma praga-chave de diversas culturas. O controle químico tem sido a principal tática de controle utilizada, embora já se tenha observado redução na eficiência dos produtos devido ao desenvolvimento de resistência. Assim, o objetivo do presente trabalho foi avaliar o efeito de diversos ésteres de sacarose com grupos alifáticos ou aromáticos sobre adultos de mosca-branca. Butirato de sacarose, caprato, octanoato, palmitato, oleato, actaacetato, ftlato, benzoato e diacetato hexaisobutirato de sacarose foram testados. Soluções de éster de sacarose foram preparadas e aplicadas sobre adultos capturados em armadilhas adesivas utilizando Torre de Potter. Ésteres alifáticos de sacarose com longas cadeias foram mais efetivos contra mosca-branca e as maiores taxas de mortalidade foram obtidas com oleato e octanoato de sacarose. Uma vez que

  20. Solvent extraction of chlorinated compounds from soils and hydrodechlorination of the extract phase.

    Science.gov (United States)

    Murena, Fabio; Gioia, Francesco

    2009-03-15

    The remediation of soils contaminated with chlorinated compounds was investigated. The process consists of solvent extraction followed by catalytic hydroprocessing (hydrodechlorination) of the extract phase. A mixture of ethylacetate-acetone-water (E-A-W) was adopted as solvent in the extraction process. Tests of extraction of chlorobenzene from a model contaminated soil were carried out and the Langmuir adsorption equation was characterized. The solvent, contaminated with different chlorinated compounds was then hydrotreated with a Pd/C catalyst. The chlorinated compounds tested are: chlorobenzene, hexachlorobenzene and hexachloroethane at various initial concentrations. The reaction runs were carried out at room temperature and at a hydrogen pressure of 1bar. Hydrotreating of these compounds takes place according to a Langmuir-Hinshelwood mechanism whose kinetic parameters were determined. The experiments show that high destruction efficiencies may be reached in reasonably short times, particularly for hexachloroethane. Longer times are necessary for the aromatic compounds (chlorobenzene and hexachlorobenzene) for which the CCl bond is much stronger than that in the aliphatic compound. Time for a 95% destruction efficiency for all experimental runs was determined. A noteworthy finding is that ethylacetate and acetone do not undergo any reaction during hydrotreating. Thus the treated extract solution may be recycled inasmuch as it conserves its full extracting capacity towards chlorinated compounds. A limitation in recycling is the inhibiting effect of benzene on the HDCl rate: benzene produced by HDCl of chlorinated compounds, accumulates in the solvent mixture in the event of recycling. Simulation of the process with the recycling of the solvent was carried out, accounting for the inhibiting effect of benzene.

  1. Synthesis of Bisphenols Carrying Long Hydrocarbon Side Chains

    Institute of Scientific and Technical Information of China (English)

    XU Jing-zhe; JIANG Nan-zhe; ZHANG Jian; JIANG Ri-shan

    2005-01-01

    Bisphenols containing long aliphatic hydrocarbon side chains were synthesized by the condensation of phenol with aldehyde or ketone in the presence of heteropolyacid. Their structures were characterized by IR, 1H NMR, 13C NMR and element analysis. The experiment results show that when heteropolyacid was used as a catalyst, these bisphenols were obtained in high selectivity and high yields.

  2. Environmental factors regulating soil organic matter chlorination

    Science.gov (United States)

    Svensson, Teresia; Montelius, Malin; Reyier, Henrik; Rietz, Karolina; Karlsson, Susanne; Lindberg, Cecilia; Andersson, Malin; Danielsson, Åsa; Bastviken, David

    2016-04-01

    Natural chlorination of organic matter is common in soils. Despite the widespread abundance of soil chlorinated soil organic matter (SOM), frequently exceeding soil chloride abundance in surface soils, and a common ability of microorganisms to produce chlorinated SOM, we lack fundamental knowledge about dominating processes and organisms responsible for the chlorination. To take one step towards resolving the terrestrial chlorine (Cl) puzzle, this study aims to analyse how environmental factors influence chlorination of SOM. Four factors were chosen for this study: soil moisture (W), nitrogen (N), chloride (Cl) and organic matter quality (C). These factors are all known to be important for soil processes. Laboratory incubations with 36Cl as a Cl tracer were performed in a two soil incubation experiments. It was found that addition of chloride and nitrogen seem to hamper the chlorination. For the C treatment, on the other hand, the results show that chlorination is enhanced by increased availability of labile organic matter (glucose and maltose). Even higher chlorination was observed when nitrogen and water were added in combination with labile organic matter. The effect that more labile organic matter strongly stimulated the chlorination rates was confirmed by the second separate experiment. These results indicate that chlorination was not primarily a way to cut refractory organic matter into digestible molecules, representing one previous hypothesis, but is related with microbial metabolism in other ways that will be further discussed in our presentation.

  3. Effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate were evaluated through different kinetics studies. Since chlorine was an electron withdrawing atom, the substitution of chlorine on the aromatic ring decreased the oxidation rate constant by σ-electron withdrawing conductive effect; at the same time, the substitution of chlorine at ortho or para position on the aromatic ring increased the oxidation rate constant by π-electron donating conjugative effect, and the conjugative effect could counteract the negative impact of the conductive effect to some extent. On the other hand, the substitution of chlorine at ortho position on the aromatic ring decreased the oxidation rate constant by steric hindrance effect. The oxidation rate constants of phenol and chlorinated phenols studied decreased as follow order: 4-chlorophenol>2,4-dichlorophenol>phenol>2,6-dichlorophenol.

  4. Effect of chain flexibility in the network structure on the viscoelasticity of epoxy thermosets

    NARCIS (Netherlands)

    Nakka, J.S.; Jansen, K.M.B.; Ernst, L.J.

    2011-01-01

    In this paper a detailed study in investigating the effect of the chain flexibility in epoxy-amine crosslinked network is done. In order to introduce flexibility into the crosslinked network a homologous series of four aliphatic diamine curing agents varying only in the chain length and having a con

  5. Characterization of Chlorinated Aliphatic Hydrocarbons and Environmental Variables in a Shallow Groundwater in Shanghai Using Kriging Interpolation and Multifactorial Analysis.

    Directory of Open Access Journals (Sweden)

    Qiang Lu

    Full Text Available CAHs, as a cleaning solvent, widely contaminated shallow groundwater with the development of manufacturing in China's Yangtze River Delta. This study focused on the distribution of CAHs, and correlations between CAHs and environmental variables in a shallow groundwater in Shanghai, using kriging interpolation and multifactorial analysis. The results showed that the overall CAHs plume area (above DIV was approximately 9,000 m(2 and located in the 2-4 m underground, DNAPL was accumulated at an area of approximately 1,400 m(2 and located in the 6-8m sandy silt layer on the top of the muddy silty clay. Heatmap of PPC for CAHs and environmental variables showed that the correlation between "Fe(2+" and most CAHs such as "1,1,1-TCA", "1,1-DCA", "1,1-DCE" and "%TCA" were significantly positive (p<0.001, but "%CA" and/or "%VC" was not, and "Cl-" was significantly positive correlated with "1,1-DCA" and "1,1-DCE" (p<0.001. The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation. In conclusion, the combination of geographical and chemometrics was helpful to establishing an aerial perspective of CAHs and identifying reasons for the accumulation of toxic dechlorination intermediates, and could become a useful tool for characterizing contaminated sites in general.

  6. Characterization of Chlorinated Aliphatic Hydrocarbons and Environmental Variables in a Shallow Groundwater in Shanghai Using Kriging Interpolation and Multifactorial Analysis.

    Science.gov (United States)

    Lu, Qiang; Luo, Qi Shi; Li, Hui; Liu, Yong Di; Gu, Ji Dong; Lin, Kuang Fei; Fei Lin, Kuang

    2015-01-01

    CAHs, as a cleaning solvent, widely contaminated shallow groundwater with the development of manufacturing in China's Yangtze River Delta. This study focused on the distribution of CAHs, and correlations between CAHs and environmental variables in a shallow groundwater in Shanghai, using kriging interpolation and multifactorial analysis. The results showed that the overall CAHs plume area (above DIV) was approximately 9,000 m(2) and located in the 2-4 m underground, DNAPL was accumulated at an area of approximately 1,400 m(2) and located in the 6-8m sandy silt layer on the top of the muddy silty clay. Heatmap of PPC for CAHs and environmental variables showed that the correlation between "Fe(2+)" and most CAHs such as "1,1,1-TCA", "1,1-DCA", "1,1-DCE" and "%TCA" were significantly positive (p<0.001), but "%CA" and/or "%VC" was not, and "Cl-" was significantly positive correlated with "1,1-DCA" and "1,1-DCE" (p<0.001). The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation. In conclusion, the combination of geographical and chemometrics was helpful to establishing an aerial perspective of CAHs and identifying reasons for the accumulation of toxic dechlorination intermediates, and could become a useful tool for characterizing contaminated sites in general.

  7. In-situ Substrate Addition to Create Reactive Zones for Treatment of Chlorinated Aliphatic Hydrocarbons: Cost and Performance Report

    Science.gov (United States)

    2007-03-01

    Environmental Restoration Program DGGE denaturing gel electrophoresis DNAPL dense, non-aqueous phase liquid DO dissolved oxygen DOC dissolved organic...cadmium, mercury , and uranium. 2.4 ADVANTAGES AND LIMITATIONS OF THE TECHNOLOGY As late as 1998, the conventional remediation option for sites...aquifers can pose problematic microbial ecology. • Effectiveness on large pools of free-phase dense, non-aqueous phase liquid ( DNAPL ) has not been

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

    Science.gov (United States)

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

    2015-06-01

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

  9. Decarboxylative Fluorination of Aliphatic Carboxylic Acids via Photoredox Catalysis.

    Science.gov (United States)

    Ventre, Sandrine; Petronijevic, Filip R; MacMillan, David W C

    2015-05-06

    The direct conversion of aliphatic carboxylic acids to the corresponding alkyl fluorides has been achieved via visible light-promoted photoredox catalysis. This operationally simple, redox-neutral fluorination method is amenable to a wide variety of carboxylic acids. Photon-induced oxidation of carboxylates leads to the formation of carboxyl radicals, which upon rapid CO2-extrusion and F(•) transfer from a fluorinating reagent yield the desired fluoroalkanes with high efficiency. Experimental evidence indicates that an oxidative quenching pathway is operable in this broadly applicable fluorination protocol.

  10. Synthesis and Characterization of Aliphatic-Aromatic Hyperbranched Polyesters

    Institute of Scientific and Technical Information of China (English)

    唐黎明; 张晓龙; 邱藤; 刘德山

    2002-01-01

    Hyperbranched polymers possess special architectures and have potential applications in various areas. In this study, two AB2 monomers, dipropyl 5-(hydroxyethoxy) isophthalate (I) and 5-hydroxyethoxyisophthaic acid (II), were prepared. By bulk polycondensation of each monomer, two aliphatic-aromatic hyperbranched polyesters were prepared and characterized by 1H-nuclear magnetic resonance (1H-NMR), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). Compared with all-aromatic hyperbranched polyesters, the prepared polymers showed lower glass transition temperatures in connection with the moderate decrease in their decomposition temperatures.

  11. Synthesis of aliphatic amidediol and used as a novel mixed plasticizer for thermoplastic starch

    Institute of Scientific and Technical Information of China (English)

    Jian She Zhang; Jiu Gao Yu; Ying Wu; Xiao Fei Ma

    2008-01-01

    In this paper,aliphatic amidediol was synthesized and mixed with glycerol used as a plasticizer for preparing thermoplastic starch (AGPTPS).The yield of aliphatic amidediol was 91%.FT-IR expressed that the mixture of aliphatic amidediol and glycerol formed stronger and stable hydrogen bond with starch molecules compared to the native cornstarch.By scanning electron microscope (SEM) native cornstarch granules were proved to transfer to a homogeneous continuous system.After being stored for a period time at room temperature,the mechanical properties of AGPTPS were also studied.As a mixed plasticizer,aliphatic amidediol and glycerol would be practical to extend TPS application scopes.

  12. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  13. Lipidic ionic liquid stationary phases for the separation of aliphatic hydrocarbons by comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Nan, He; Zhang, Cheng; O'Brien, Richard A; Benchea, Adela; Davis, James H; Anderson, Jared L

    2017-01-20

    Lipidic ionic liquids (ILs) possessing long alkyl chains as well as low melting points have the potential to provide unique selectivity as well as wide operating ranges when used as stationary phases in gas chromatography. In this study, a total of eleven lipidic ILs containing various structural features (i.e., double bonds, linear thioether chains, and cyclopropanyl groups) were examined as stationary phases in comprehensive two dimensional gas chromatography (GC×GC) for the separation of nonpolar analytes in kerosene. N-alkyl-N'-methyl-imidazolium-based ILs containing different alkyl side chains were used as model structures to investigate the effects of alkyl moieties with different structural features on the selectivities and operating temperature ranges of the IL-based stationary phases. Compared to a homologous series of ILs containing saturated side chains, lipidic ILs exhibit improved selectivity toward the aliphatic hydrocarbons in kerosene. The palmitoleyl IL provided the highest selectivity compared to all other lipidic ILs as well as the commercial SUPELCOWAX 10 column. The linoleyl IL containing two double bonds within the alkyl side chain showed the lowest chromatographic selectivity. The lipidic IL possessing a cyclopropanyl group within the alkyl moiety exhibited the highest thermal stability. The Abraham solvation parameter model was used to evaluate the solvation properties of the lipidic ILs. This study provides the first comprehensive examination into the relation between lipidic IL structure and the resulting solvation characteristics. Furthermore, these results establish a basis for applying lipidic ILs as stationary phases for solute specific separations in GC×GC.

  14. Reactions of aqueous chlorine and chlorine dioxide with model food compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fukayama, M.Y.; Tan, H.; Wheeler, W.B.; Wei, C.

    1986-11-01

    This presentation reviews published information concerning the reactions of chlorine gas (CL/sub 2/(g)), aqueous chlorine, and ClO/sub 2/ with model food compounds, the fate of chlorine during the chlorination of specific food products, and the potential toxicity of the reaction products. Fatty acids and their methyl esters react with chlorine with the degree of incorporation corresponding to their degree of unsaturation. Aqueous chlorine oxidizes and chlorinates lipids and amino acids much more readily than ClO/sub 2/. Several amino acids are highly susceptible to oxidation and chlorination by chlorine compounds. Reactions of chlorine and ClO/sub 2/ with several food products, including flour and shrimp, have also been characterized. Although significant quantities of chlorine can be incorporated into specific model compounds and food products, the health risks associated with exposure to chlorinated organic products are unknown. Preliminary studies using the Ames Salmonella/microsome mutagenicity assay indicate that the reaction products from mixtures of aqueous chlorine and various lipids or tryptophan are nonmutagenic. Nevertheless, additional studies are warranted, so that the toxicological significance of these reaction products can be understood more fully.

  15. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  16. Characterization, Distribution, Sources and Origins of Aliphatic Hydrocarbons from Surface Sediment of Prai Strait, Penang, Malaysia: A Widespread Anthropogenic Input

    Directory of Open Access Journals (Sweden)

    Mahyar Sakari

    2008-07-01

    Full Text Available Persistent organic pollutants such as petroleum hydrocarbons are one of the most serious and important class of pollutants that face to many countries including Malaysia. Aliphatic hydrocarbons contain straight chain alkane; derive from anthropogenic and natural sources to the marine environment. The multi-purpose strait of Prai is located in the Northwest of Peninsular Malaysia plays an important economic role in the Southeast Asia. Twenty surface sediment samples were collected using Eckman dredge to measure the concentration and determine the characterization, sources and origins of the aliphatic hydrocarbons in December 2006. Samples (top 4 cm were extracted with Soxhlet, treated with activated copper and subjected to 2 steps column chromatography for purification and fractionation. Alkane fraction injected into Gas Chromatography–Flame Ionization Detector (GC-FID for instrumental analysis. The results showed that total n-alkane concentrations are ranging from 512 to 10770 ng/mg d. w. Carbon Preferences Index (CPI revealed an extreme widespread anthropogenic input and naturally derived (CPI= 0 to 4.88 hydrocarbons in the study area. The ratio of C31/C19 indicated that natural hydrocarbons are generating from terrestrial vascular plants and transferring by rivers. The characteristics of Major Hydrocarbons provided evidences that oil and its derivatives either fresh or degraded are the major contributors of the pollution in the study area. Statistical approaches also confirmed that 85% of study area affected by oil sources of pollution. It is seen that aliphatic hydrocarbons mostly transfer by lateral input to the marine environment than atmospheric movements.

  17. Catalytic hydrogen-chlorine exchange between chlorinated hydrocarbons under oxygen-free conditions

    NARCIS (Netherlands)

    van der Heijden, A.W.A.M.; Podkolzin, S.G.; Jones, M.E.; Bitter, J.H.; Weckhuysen, B.M.

    2008-01-01

    Chlorinated hydrocarbons (CHCs) remain important industrial chemical intermediates and solvents, especially for the exploration of the potential of La-based materials for the conversion of chlorinated waste compounds.[1] The production of industrially important CHCs frequently occurs with concurrent

  18. Study on the Synthesis and Biodegradation of Aliphatic Polyester

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm)and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1mm) after burying in soil for 36 days.

  19. Chemical composition of pseudo-phlobaphinite precursors: implications for the presence of aliphatic biopolymers in vitrinite from coal

    Energy Technology Data Exchange (ETDEWEB)

    Etuan Zhang; Hatcher, P.G.; Davis, A. (Pennsylvania State University, University Park, PA (United States). Dept. of Materials Science and Engineering)

    1993-08-01

    Pseudo-phlobaphinite cell inclusions in a buried stem of angiospermous wood of [ital Rhizophora mangle] from Mangrove Lake, Bermuda have been investigated petrographically and chemically. Optical and scanning electron microscopy reveal that the light wood from inner sections of the stem consists predominantly of cell walls with few cell inclusions, whereas the dark wood from outer portion of the stem is composed of both cell walls and cell inclusions which are believed to represent pseudophlobaphinite precursors. [sup 13]C NMR spectroscopy reveals the presence of lignin and tannin structures within the cell walls. The wood also displays resonances suggestive of aliphatic components. The NMR results are further supplemented and confirmed by flash pyrolysis gas chromatography and mass spectrometry analyses. The pyrogram of the cell-wall dominated light wood is characterized by peaks related to both syringyl and guaiacyl units. The major pyrolysis products from the dark wood, however, are a homologous series of long-chain n-alkanes, n-alk-l-enes and [alpha],[omega]-alkadienes extending from chain length C[sub 10] to C[sub 30]. These aliphatic components arise from the material associated with the pseudophlobaphinite cell inclusions. Py-gc/ms analysis of a humic acid extracted from the sediments surrounding the studied wood consists almost exclusively of a homologous series of straight-chain alkanes, alkenes and alkadienes up to C[sub 30]. The striking resemblance between programs of the pseudo-phlobaphinite precursor and humic acid suggests that the possible mechanism for the formation of the pseudo-phlobaphinite is migration and deposition of humic acid into cell lumina. 72 refs., 5 figs., 1 tab.

  20. Spatial distribution, temporal variation and risks of parabens and their chlorinated derivatives in urban surface water in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wenhui; Gao, Lihong [School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Shi, Yali; Wang, Yuan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085 (China); Liu, Jiemin, E-mail: liujm@ustb.edu.cn [School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Cai, Yaqi, E-mail: caiyaqi@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085 (China)

    2016-01-01

    The occurrence and distribution of 13 target compounds, including eight parabens, four chlorinated parabens and p-hydroxybenzoic acid (PHBA), were detected in surface water samples at 35 sampling sites in the Beijing River system, China. The surface water samples were collected from the main rivers and lakes in the urban area monthly from July 2013 to June 2014 (except the frozen period). Laboratory analyses revealed that parabens were ubiquitous in the surface water of Beijing. PHBA was the predominant compound in the surface water samples, with the average concentration of 239 ng L{sup −1}, followed by the total amount of chlorinated parabens (average 50.1 ng/L) and parabens (average 44.3 ng/L). It is noteworthy that octylparaben with longer chain was firstly detected in the surface water. Significant difference was observed for paraben concentrations from different sampling sites, and the highest level of parabens was found in the Xiaotaihou River, which was mainly due to the untreated sewage discharge. Seasonal variation of target compounds in the urban surface water was also studied, and parabens exhibited a different temporal variation from chlorinated derivatives. A combination of factors including high residual chlorine level and water temperature as well as intense ultraviolet radiation might enhance the persistence of chlorinated parabens in chlorinated water during the wet season. Risk assessment showed that parabens and their chlorinated derivatives are not likely to produce biological effects on aquatic ecosystems at current levels in the surface water of Beijing. - Highlights: • Parabens and chlorinated parabens are ubiquitous in surface water in Beijing. • Octylparaben with longer chain was firstly detected in surface water. • Untreated sewage discharge was the main source of parabens in river. • Parabens exhibited a different seasonal variation from chlorinated derivatives. • The risks of target compounds are negligible at

  1. Short chain aliphatic acid anions in oil field waters and their contribution to the measured alkalinity

    Science.gov (United States)

    Willey, L.M.; Kharaka, Y.K.; Presser, T.S.; Rapp, J.B.; Barnes, I.

    1975-01-01

    High alkalinity values found in some formation waters from Kettleman North Dome oil field are due chiefly to acetate and propionate ions, with some contribution from higher molecular weight organic acid ions. Some of these waters contain no detectable bicarbonate alkalinity. For waters such as these, high supersaturation with respect to calcite will be incorrectly indicated by thermodynamic calculations based upon carbonate concentrations inferred from traditional alkalinity measurements. ?? 1975.

  2. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  3. The chlorination of cyclopentanone and cyclohexanone

    NARCIS (Netherlands)

    Maatman, Hendrik

    1980-01-01

    In this thesis the results of an investigation of the chlorination of cyclopentanone and cyclohexanone in the solvent carbontetrachloride and catalyzed by hydrogen chloride are described. ... Zie: Summary

  4. High resolution spectrophotometry for identification of chlorine dioxide in concentrated chlorine solutions.

    Science.gov (United States)

    Gauw, R D; Emmert, G L; Bubnis, B; Gordon, G

    1999-12-06

    Electrolyzed salt brine generators hold great promise for water disinfection in small communities and remote locations. Electrolysis cell liquors have been reported to contain chlorine, chlorine dioxide and ozone. High resolution spectrophotometry was used to observe the presence (or absence) of a unique spectral absorbance pattern present in solutions containing 1-2 mg/l chlorine dioxide.

  5. Durability of Selected Membrane Materials when Exposed to Chlorine Gas

    Energy Technology Data Exchange (ETDEWEB)

    Eikeland, Marianne Soerflaten

    2001-03-01

    This thesis is focusing on the durability of selected membrane materials when exposed to chlorine gas in the temperature range 30-100{sup o}C. Studies of the changes of membrane separation properties and the mechanisms promoting these changes have been studied. The selected membrane materials were poly(dimethylsioxane) (PDMS), Fluorel, fluorosilicone, and blends of PDMS and Fluorel. The thesis is organised in seven chapters. The first chapter gives an introduction to the background of the work. The second chapter presents the theory for gas separation using dense rubbery membranes. The properties of the selected membrane materials are presented in chapter three. The fourth chapter describes degradation mechanisms for polymeric materials in general and for the selected membrane materials in particular. Presentation of the experimental work is given in chapter five, while the results with discussions are presented in chapter six. The conclusions and recommendations for further studies are given in chapter seven. Five appendixes are attached: Appendix A describes the calculations of permeability and solubility coefficients and the accuracy of the experimental measurements. Appendix B summarises the measured values in tables and Appendix C describes the analytical methods. Appendix D gives the properties of the gases used in the experiments. Appendix E is the article ''Durability of Poly(dimethylsiloxane) when Exposed to Chlorine Gas'', submitted to the Journal of Applied Polymer Science. Highly crosslinked PDMS was found to have an initial high permeability for chlorine gas and a high Cl{sub 2}/O{sub 2} selectivity. However when exposed to chlorine gas the permeability decreased significantly. Crosslinking of the PDMS polymer chain and chlorination of the polymer gave a denser polymer structure and thus lower permeability. Fluorel showed very low permeabilities and selectivities for the gases in question and was thus not interesting for this

  6. Ion-Exclusion High-Performance Liquid Chromatography of Aliphatic Organic Acids Using a Surfactant-Modified C18 Column.

    Science.gov (United States)

    Fasciano, Jennifer M; Mansour, Fotouh R; Danielson, Neil D

    2016-07-01

    Ion exclusion chromatography (IELC) of short chain aliphatic carboxylic acids is normally done using a cation exchange column under standard HPLC conditions but not in the ultra-HPLC (UHPLC) mode. A novel IELC method for the separation of this class of carboxylic acids by either HPLC or UHPLC utilizing a C18 column dynamically modified with sodium dodecyl sulfate has been developed. The sample capacity is estimated to be near 10 mM for a 20 µL injection or 0.2 µmol using a 150 × 4.6 mm column. The optimum mobile phase determined for three standard mixtures of organic acids is 1.84 mM sulfuric acid at pH 2.43 and a flow rate of 0.6 mL/min. Under optimized conditions, a HPLC separation of four aliphatic carboxylic acids such as tartaric, malonic, lactic and acetic can be achieved in under 4 min and in column as measured by the retention order of maleic and fumaric acid is estimated to be ∼4,000 column volumes using HPLC and 600 by UHPLC. Reproducible chromatograms are achieved over at least a 2-month period. This study shows that the utility of a C18 column can be easily extended when needed to IELC under either standard or UHPLC conditions.

  7. Forensic investigation of aliphatic hydrocarbons in the sediments from selected mangrove ecosystems in the west coast of Peninsular Malaysia.

    Science.gov (United States)

    Vaezzadeh, Vahab; Zakaria, Mohamad Pauzi; Shau-Hwai, Aileen Tan; Ibrahim, Zelina Zaiton; Mustafa, Shuhaimi; Abootalebi-Jahromi, Fatemeh; Masood, Najat; Magam, Sami Mohsen; Alkhadher, Sadeq Abdullah Abdo

    2015-11-15

    Peninsular Malaysia has gone through fast development during recent decades resulting in the release of large amounts of petroleum and its products into the environment. Aliphatic hydrocarbons are one of the major components of petroleum. Surface sediment samples were collected from five rivers along the west coast of Peninsular Malaysia and analyzed for aliphatic hydrocarbons. The total concentrations of C10 to C36 n-alkanes ranged from 27,945 to 254,463ng·g(-1)dry weight (dw). Evaluation of various n-alkane indices such as carbon preference index (CPI; 0.35 to 3.10) and average chain length (ACL; 26.74 to 29.23) of C25 to C33 n-alkanes indicated a predominance of petrogenic source n-alkanes in the lower parts of the Rivers, while biogenic origin n-alkanes from vascular plants are more predominant in the upper parts, especially in less polluted areas. Petrogenic sources of n-alkanes are predominantly heavy and degraded oil versus fresh oil inputs.

  8. Regioselective oxygenation of fatty acids, fatty alcohols and other aliphatic compounds by a basidiomycete heme-thiolate peroxidase.

    Science.gov (United States)

    Gutiérrez, Ana; Babot, Esteban D; Ullrich, René; Hofrichter, Martin; Martínez, Angel T; del Río, José C

    2011-10-01

    Reaction of fatty acids, fatty alcohols, alkanes, sterols, sterol esters and triglycerides with the so-called aromatic peroxygenase from Agrocybe aegerita was investigated using GC-MS. Regioselective hydroxylation of C(12)-C(20) saturated/unsaturated fatty acids was observed at the ω-1 and ω-2 positions (except myristoleic acid only forming the ω-2 derivative). Minor hydroxylation at ω and ω-3 to ω-5 positions was also observed. Further oxidized products were detected, including keto, dihydroxylated, keto-hydroxy and dicarboxylic fatty acids. Fatty alcohols also yielded hydroxy or keto derivatives of the corresponding fatty acid. Finally, alkanes gave, in addition to alcohols at positions 2 or 3, dihydroxylated derivatives at both sides of the molecule; and sterols showed side-chain hydroxylation. No derivatives were found for fatty acids esterified with sterols or forming triglycerides, but methyl esters were ω-1 or ω-2 hydroxylated. Reactions using H(2)(18)O(2) established that peroxide is the source of the oxygen introduced in aliphatic hydroxylations. These studies also indicated that oxidation of alcohols to carbonyl and carboxyl groups is produced by successive hydroxylations combined with one dehydration step. We conclude that the A. aegerita peroxygenase not only oxidizes aromatic compounds but also catalyzes the stepwise oxidation of aliphatic compounds by hydrogen peroxide, with different hydroxylated intermediates.

  9. Concentration-dependence of the explosion characteristics of chlorine dioxide gas.

    Science.gov (United States)

    Jin, Ri-ya; Hu, Shuang-qi; Zhang, Yin-ghao; Bo, Tao

    2009-07-30

    The explosion characteristics of chlorine dioxide gas have been studied for the first time in a cylindrical exploder with a shell capacity of 20 L. The experimental results have indicated that the lower concentration limit for the explosive decomposition of chlorine dioxide gas is 9.5% ([ClO(2)]/[air]), whereas there is no corresponding upper concentration limit. Under the experimental conditions, and within the explosion limits, the pressure of explosion increases with increasing concentration of chlorine dioxide gas; the maximum pressure of explosion relative to the initial pressure was measured as 0.024 MPa at 10% ClO(2) and 0.641 MPa at 90% ClO(2). The induction time (the time from the moment of sparking to explosion) has also been found to depend on the concentration of chlorine dioxide gas; thus, at 10% ClO(2) the induction time was 2195 ms, but at 90% ClO(2) the induction time was just 8 ms. The explosion reaction mechanism of ClO(2) is of a degenerate chain-branching type involving the formation of a stable intermediate (Cl(2)O(3)), from which the chain-branching occurs. Chain initiation takes place at the point of ignition and termination takes place at the inner walls of the exploder.

  10. Facile synthesis of aliphatic isothiocyanates and thioureas on solid phase using peptide coupling reagents

    DEFF Research Database (Denmark)

    Boas, Ulrik; Andersen, Heidi Gertz; Christensen, Jørn B.;

    2004-01-01

    Peptide coupling reagents can be used as versatile reagents for the formation of aliphatic isothiocyanates and thioureas on solid phase from the corresponding solid-phase anchored aliphatic primary amines. The formation of the thioureas is fast and highly chemoselective, and proceeds via formation...

  11. 40 CFR 721.530 - Substituted aliphatic acid halide (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted aliphatic acid halide... Specific Chemical Substances § 721.530 Substituted aliphatic acid halide (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance substituted...

  12. A Theoretical Study on the Vibrational Spectra of PAH Molecules with Aliphatic Sidegroups

    CERN Document Server

    Sadjadi, SeyedAbdolreza; Kwok, Sun

    2015-01-01

    The role of aliphatic side groups on the formation of astronomical unidentified infrared emission (UIE) features is investigated by applying the density functional theory (DFT) to a series of molecules with mixed aliphatic-aromatic structures. The effects of introducing various aliphatic groups to a fixed polycyclic aromatic hydrocarbon (PAH) core (ovalene) are studied. Simulated spectra for each molecule are produced by applying a Drude profile at $T$=500 K while the molecule is kept at its electronic ground state. The vibrational normal modes are classified using a semi-quantitative method. This allows us to separate the aromatic and aliphatic vibrations and therefore provide clues to what types of vibrations are responsible for the emissions bands at different wavelengths. We find that many of the UIE bands are not pure aromatic vibrational bands but may represent coupled vibrational modes. The effects of aliphatic groups on the formation of the 8 $\\mu$m plateau are qua ntitatively determined. The vibratio...

  13. Low—Molecular—Weight Aliphatic Acids in Soils Inculbated with Plant Residues Under Different Moisture Conditions

    Institute of Scientific and Technical Information of China (English)

    SHENALIN; LIXUEYUAN; 等

    1997-01-01

    Iucubation experiments were conducted to investigate the dynamics of low-molecular-weight aliphatic acids i two andosols with and without plant materials.Results showed that amount of low-molecular-weight aliphatic acids in soils alone varied considerably with water regime under which the soil was incubated,duration of incubation and soil organic matter content,ranging from 257-860μmol kg-1 soil,of which 19%-33% was in free state.Incorporation of plant matrials increased greatly both the amount and unmber of members of low-molecular-weight aliphatic acids,and also the proportion of low-molecular-weght aliphatic acids occurred in free state ,Generally,among these ,aliphatic acids detected,acetic,propionic,glyoxalic and formic acids were predominant.

  14. Inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine.

    OpenAIRE

    Berman, D; Hoff, J C

    1984-01-01

    The kinetics of inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine were studied at 5 degrees C with a purified preparation of single virions and a preparation of cell-associated virions. Inactivation of the virus preparations with chlorine and chlorine dioxide was studied at pH 6 and 10. The monochloramine studies were done at pH 8. With 0.5 mg of chlorine per liter at pH 6, more than 4 logs (99.99%) of the single virions were inactivated in less than 15 s...

  15. Characterization of aliphatic hydrocarbons in deep subsurface soils near the outskirts of Beijing, China

    Institute of Scientific and Technical Information of China (English)

    ZHU You-feng; LIU Hui; XI Zhi-qun; CHENG Hang-xin; XU Xiao-bai

    2005-01-01

    Thirty-nine deep subsurface soils( 150-180 Gm depth) near the outskirts of Beijing were investagated. The concentrations including n-alkanes from C13 to C36, pristane and phytane were in the range of 0.60 to 170.10 μg/g, with a median value of 4.26. Carbon preference index values for n-alkanes ranged from 1.08 to 2.98, with a median value of 1.48. The percentage contribution of "wax" nalkanes was in the range of 6.03%-46.22%. A predominance of odd/even carbon n-alkanes and unresolved complex mixtures with different shapes and ranges were frequently observed. Factor analysis reduced the data set into three principal components and confirming contributions from Iow ( 19.58%), medium (20.49%) molecular weight species and long-chain n-alkanes (43.41%), respectively.Molecular biomarkers such as pristane, phytane, hopanes and steranes were detected. Based on the principal component analysis, the concentration profiles and molecular markers, it was found that the aliphatic hydrocarbons were from both biogenic and anthropogenic sources.

  16. Syntheses, structures, and properties of multidimensional lithium coordination polymers based on aliphatic carboxylic acids.

    Science.gov (United States)

    Cheng, Pei-Chi; Lin, Wei-Cheng; Tseng, Feng-Shuen; Kao, Ching-Che; Chang, Ting-Guang; Senthil Raja, Duraisamy; Liu, Wei-Ren; Lin, Chia-Her

    2013-02-28

    Three lithium coordination polymers, [Li4(H2O)2(EDTA)] (1), [Li4(H2O)4(BTCA)] (2), and (H2NMe2)2[Li2(H2O)2(BTCA)] (3) (H4EDTA = ethylenediaminetetraacetic acid, H4BTCA = 1,2,3,4-butane tetracarboxylic acid, H2NMe2 = dimethyl amine), have been synthesized by reacting lithium salts with aliphatic carboxylic acids using a solvothermal method. The structures of all the three complexes have been determined by single crystal X-ray diffraction studies. The single crystal structure analysis revealed that complex 1 has a three-dimensional framework, whereas complex 2 has 2D sheets and complex 3 has 1D chains. In addition, these lithium complexes contain various inorganic motifs with a tetramer in 1 and 2, and discrete tetrahedra in 3 and have further been connected through organic ligands to construct multidimensional structures. Further, the electrochemical properties of complexes 1–3 have been studied to evaluate these compounds as electrode materials for lithium ion batteries with discharge capacities of around 100 mA h g(-1) in the first thirty cycles.

  17. The photoreactivity of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vaida, V. [Univ. of Colorado, Boulder, CO (United States); Simon, J.D. [Univ. of California, San Diego, La Jolla, CA (United States)

    1995-06-09

    Determining the detailed photoreactivity of radicals that are of importance in atmospheric processes requires information from both laboratory and field measurements and theoretical calculations. Laboratory experiments and quantum calculations have been used to develop a comprehensive understanding of the photoreactivity of chlorine dioxide (OClO). The photoreactivity is strongly dependent on the medium (gas phase, liquid solution, or cryogenic matrix). These data reveal details of the complex chemistry of OClO. The potential role of this radical in stratospheric ozone depletion is discussed in accord with these laboratory measurements. 53 refs., 4 figs.

  18. Vapour pressure and enthalpy of vaporization of aliphatic dialkyl carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Kozlova, Svetlana A.; Emel' yanenko, Vladimir N.; Georgieva, Miglena [Department of Physical Chemistry, University of Rostock, Hermannstrasse 14, D-18051 Rostock (Germany); Verevkin, Sergey P. [Department of Physical Chemistry, University of Rostock, Hermannstrasse 14, D-18051 Rostock (Germany)], E-mail: sergey.verevkin@uni-rostock.de; Chernyak, Yury [Huntsman Corporation, Advanced Technology Center, 8600 Gosling Road, The Woodlands, TX 77381 (United States); Schaeffner, Benjamin; Boerner, Armin [Leibniz Institut fuer Katalyse an der Universitaet Rostock e.V., Albert-Einstein Strasse 29a, 18059 Rostock (Germany)

    2008-07-15

    Molar enthalpies of vaporization of aliphatic alkyl carbonates: dimethyl carbonate [616-38-6], diethyl carbonate [105-58-8], di-n-propyl carbonate [623-96-1], di-n-butyl carbonate [542-52-9], and dibenzyl carbonate [3459-92-5] were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. A large number of the primary experimental results on temperature dependences of vapour pressures have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies of dialkyl carbonates at the reference temperature 298.15 K. An internal consistency check was performed on enthalpy of vaporization values for dialkyl carbonates studied in this work.

  19. Aqueous infrared carboxylate absorbances: Aliphatic di-acids

    Science.gov (United States)

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

    1998-01-01

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

  20. Localized aliphatic organic material on the surface of Ceres

    Science.gov (United States)

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

    2017-02-01

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

  1. Spatial distribution, temporal variation and risks of parabens and their chlorinated derivatives in urban surface water in Beijing, China.

    Science.gov (United States)

    Li, Wenhui; Gao, Lihong; Shi, Yali; Wang, Yuan; Liu, Jiemin; Cai, Yaqi

    2016-01-01

    The occurrence and distribution of 13 target compounds, including eight parabens, four chlorinated parabens and p-hydroxybenzoic acid (PHBA), were detected in surface water samples at 35 sampling sites in the Beijing River system, China. The surface water samples were collected from the main rivers and lakes in the urban area monthly from July 2013 to June 2014 (except the frozen period). Laboratory analyses revealed that parabens were ubiquitous in the surface water of Beijing. PHBA was the predominant compound in the surface water samples, with the average concentration of 239ngL(-1), followed by the total amount of chlorinated parabens (average 50.1ng/L) and parabens (average 44.3ng/L). It is noteworthy that octylparaben with longer chain was firstly detected in the surface water. Significant difference was observed for paraben concentrations from different sampling sites, and the highest level of parabens was found in the Xiaotaihou River, which was mainly due to the untreated sewage discharge. Seasonal variation of target compounds in the urban surface water was also studied, and parabens exhibited a different temporal variation from chlorinated derivatives. A combination of factors including high residual chlorine level and water temperature as well as intense ultraviolet radiation might enhance the persistence of chlorinated parabens in chlorinated water during the wet season. Risk assessment showed that parabens and their chlorinated derivatives are not likely to produce biological effects on aquatic ecosystems at current levels in the surface water of Beijing.

  2. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability

    Energy Technology Data Exchange (ETDEWEB)

    Korich, D.G.; Mead, J.R.; Madore, M.S.; Sinclair, N.A.; Sterling, C.R. (Univ. of Arizona, Tucson (USA))

    1990-05-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.

  3. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    Science.gov (United States)

    Korich, D G; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water. PMID:2339894

  4. Hydrolytic And Enzymatic Degradation Characteristics Of Biodegradable Aliphatic Polysters

    Institute of Scientific and Technical Information of China (English)

    LI Suming

    2004-01-01

    Aliphatic polyesters, especially those derived from lactide (PLA), glycolide (PGA) and ε-caprolactone (PCL), are being investigated worldwide for applications in the field of surgery (suture material, devices for internal bone fracture fixation), pharmacology (sustained drug delivery systems), and tissue engineering (scaffold for tissue regeneration) [1,2]. This is mainly due to their good biocompatibility and variable degradability. These polymers present also a growing interest for environmental applications in agriculture (mulch films) and in our everyday life (packaging material)as the development of biodegradable materials is now considered as one of the potential solutions to the problem of plastic waste management.For both biomedical and environmental applications, it is of major importance to understand the degradation characteristics of the polymers. The hydrolytic degradation of aliphatic polyesters has been investigated by many research groups. Our group has shown that degradation of PLAGA large size devices is faster inside than at the surface. This heterogeneous degradation is due to the autocatalytic effect of carboxylic endgroups formed by ester bond cleavage. Moreover,degradation-induced morphological and compositional changes were also elucidated. In the case of PCL, the hydrolytic degradation is very slow due to its hydrophobicity and crystallinity.The enzymatic degradation of these polymers has been investigated by a number of authors. A specific enzyme, proteinase K, has been shown to have significant effects on PLA degradation. This enzyme preferentially degrade L-lactate units as opposed to D-lactate ones, amorphous zones as opposed to crystalline ones [3]. The enzymatic degradation of PCL polymers has also been investigated. A number of lipase-type enzymes were found to significantly accelerate the degradation of PCL despite its high crystallinity. In the case of PLA/PCL blends, the two components exhibited well separated crystalline domains

  5. Mutagenic compounds from chlorination of humic substances

    Science.gov (United States)

    Holmbom, Bjarne

    Chlorination of natural humic substances, as well as of lignin, produces a myriad of non-chlorinated and chlorinated compounds. The identification of an important class of strongly mutagenic compounds is reviewed. The most important Ames mutagen in chlorinated drinking waters of various origin is the compound 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone ("MX"). This compound occurs at neutral pH in the acyclic form, i.e. in the form of Z-2-chloro-3-(dichloromethyl)-4-oxobutenoic acid. Its E-isomer (E-MX) is present in chlorinated drinking waters at a similar concentration, but is less mutagenic in Ames test. Both oxidised and reduced forms of MX and E-MX are also present in chlorinated waters. The present knowledge of the chemistry and toxicology of these mutagens is examined. The formation and possible elimination of the chlorination mutagens is discussed. The need of understanding the mechanisms of formation of these mutagens from humic substances during drinking water chlorination is emphasized.

  6. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  7. Chlorine and carbon isotope measurements can help assessing the effectivenes of a zero valent iron barrier

    Science.gov (United States)

    Cretnik, S.; Audi, C.; Bernstein, A.; Palau, J.; Soler, A.; Elsner, M.

    2012-04-01

    Chlorinated aliphatic hydrocarbons (CAH's) such as trichloroethene (TCE), cis-dichloroethene (cis-DCE) and vinylchloride (VC) are extensively used in industrial applications. One of the most promising remediation techniques for CAH's in groundwater is their removal via abiotic reductive dechlorination using Zero Valent Iron (ZVI). This is applied for the treatment of contaminated sites by installing permeable reactive barriers (PRB). In this study, isotope fractionation of chlorinated ethylenes in transformation by cast iron has been investigated, because such types of iron are commonly used in PRBs. Batch experiments have been carried out in closed flasks, containing cast iron with aqueous solutions of TCE, cDCE and VC. These substrates and their respective products have been monitored by headspace samplings for their concentration (by GC-FID) and isotope fractionation of carbon and chlorine (by GC-IRMS). A decreasing reactivity trend was observed when compounds contain less chlorine atoms, with differences in rate constants of about one order of magnitude between each of the substances TCE > cDCE > VC. This resulted in the accumulation of products with fewer chlorine atoms. Therefore a similar observation can be expected if degradation in the field is incomplete, for example in the case of aged or improperly designed PRB. Pronounced carbon and chlorine isotope fractionation was measured for each of the compounds, and characteristic dual isotope plots (C, Cl) were obtained for TCE and cDCE. These results may serve as an important reference for the interpretation of isotope data from field sites, since stable isotope fractionation is widely recognized as robust indicator for such pollutant transformations. However, carbon isotope fractionation in a given parent compound may be caused by either abiotic or biotic degradation. In the field, it can therefore be difficult to delineate the contribution of abiotic transformation by PRB in the presence of ongoing

  8. Screening and Quantification of Aliphatic Primary Alkyl Corrosion Inhibitor Amines in Water Samples by Paper Spray Mass Spectrometry.

    Science.gov (United States)

    Jjunju, Fred P M; Maher, Simon; Damon, Deidre E; Barrett, Richard M; Syed, S U; Heeren, Ron M A; Taylor, Stephen; Badu-Tawiah, Abraham K

    2016-01-19

    Direct analysis and identification of long chain aliphatic primary diamine Duomeen O (n-oleyl-1,3-diaminopropane), corrosion inhibitor in raw water samples taken from a large medium pressure water tube boiler plant water samples at low LODs (corrosion inhibitors in an industrial water boiler plant and other related samples in the water treatment industry. This approach was applied for the analysis of three complex water samples including feedwater, condensate water, and boiler water, all collected from large medium pressure (MP) water tube boiler plants, known to be dosed with varying amounts of polyamine and amine corrosion inhibitor components. Polyamine chemistry is widely used for example in large high pressure (HP) boilers operating in municipal waste and recycling facilities to prevent corrosion of metals. The samples used in this study are from such a facility in Coventry waste treatment facility, U.K., which has 3 × 40 tonne/hour boilers operating at 17.5 bar.

  9. New soft porous frameworks based on lambda-zirconium phosphate and aliphatic dicarboxylates: Synthesis and structural characterization

    Science.gov (United States)

    Alhendawi, Hussein; Brunet, Ernesto; Juanes, Olga; Hammouda, Huda; Idhair, Salem; Rodríguez Payán, Elena; de Victoria Rodríguez, María

    2015-11-01

    New dicarboxylate-functionalized pillared materials with a general formula of λ-ZrPO4(OH)1-x(OOC(CH2)nCOO)x/2(dmso) (n=6, 8 and 10) have been prepared by post-synthesis modification of the inorganic layers of λ-zirconium phosphate (λ-ZrP), where the superficial Chloride monovalent anionic ligands of λ-layer are partially exchanged with the divalent anionic ligands of a series of long-chain aliphatic dicarboxylic acids, namely octanedioic acid, decanedioic acid and dodecanedioic acid. The synthesized materials are characterized by X-ray diffractometry, FT-IR spectrophotometry, elemental and thermogravimetric analyses. The X-ray diffraction patterns show that the obtained solid phases are pure. Furthermore, the interlayer distance of λ-ZrP systematically increases from 1.02 to 1.59 nm as a result of the incorporation of the mentioned acids inside the interlayer gallery.

  10. 40 CFR 721.3830 - Formaldehyde, reaction products with an alkylated phenol and an aliphatic amine (generic).

    Science.gov (United States)

    2010-07-01

    ... an alkylated phenol and an aliphatic amine (generic). 721.3830 Section 721.3830 Protection of... products with an alkylated phenol and an aliphatic amine (generic). (a) Chemical substance and significant..., reaction products with an alkylated phenol and an aliphatic amine (PMN P-99-0531) is subject to...

  11. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1998-12-31

    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  12. Retention behavior of a homologous series and positional isomers of aliphatic amino acids in hydrophilic interaction chromatography.

    Science.gov (United States)

    Douša, Michal; Srbek, Jan; Stránský, Zdeněk; Gibala, Petr; Nováková, Lucie

    2014-04-01

    The retention behavior of several series of free α- and ω-amino acids and positional isomers of amino pentanoic acid in the hydrophilic interaction chromatography mode (HILIC) was studied. The study was carried out on three stationary phases followed by post-column derivatization with fluorescence detection in order to describe the retention mechanism of the tested amino acids. The effect of chromatographic conditions including acetonitrile content in the mobile phase, mobile phase pH (ranging from 3.5 to 6.5) and concentration of buffer in the mobile phase was investigated. The effect of the number of carbon atoms (nC) in aliphatic chains of the individual homologue of α- and ω-amino acids and the logarithm of the partition coefficient (logD) on retention was also a part of the presented study. A good correlation (r > 0.98) between the logk and logD values of amino acids or nC, respectively, was observed. The described linear relationships were subsequently applied to predict the retention behavior of individual members of the homologous series of amino acids and to optimize the mobile phase composition in HILIC. The obtained results confirmed that the retention mechanism of α-amino acids, ω-amino acids and positional isomers of amino acids was based on the logD values and the number of carbon atoms in the aliphatic chains of amino acids. The elution order of ω-amino acids and positional isomers of amino pentanoic acid was strongly dependent on the mobile phase pH in the investigated range whereas the retention factors of all α-amino acids remained essentially unchanged on all tested stationary phases.

  13. 短链氯化石蜡C10(50.2%Cl)对斑马鱼胚胎的发育毒性%Study on developmental toxicity of short-chain chlorinated paraffins C10(50.2%Cl) in zebrafish embryos

    Institute of Scientific and Technical Information of China (English)

    刘丽华; 马万里; 刘丽艳; 李一凡

    2016-01-01

    A zebrafish ( Danio rerio ) model was applied to evaluate the developmental toxicity of short⁃chain chlorinated paraffins ( SCCPs) . Death rates, hatching rates, malformation rates and body length were observed after the zebrafish embryos were exposed to different concentrations of C10(50.2% Cl) separately for 24, 48, 72 and 96 h. The results indicated that C10(50.2% Cl) could exert lethal and sub⁃lethal effects on the early life stage of zebrafish. Higher concentrations of C10(50.2% Cl) ( 1 000 and 10 000 μg/L) could not only cause significant death rates increase to 100% after 96 h exposure and hating delay after 48 h exposure, but also induce a series of malformations, including spinal curvature, yolk deformity, pericardial edema, malformation of tail and uninflated swim bladder. Since the growth inhibition of juvenile zebrafish caused by C10 ( 50. 2% Cl ) on the exposure concentrations no matter high or low, SCCPs might be a risk to the aquatic ecology and fish development.%为评价短链氯化石蜡对斑马鱼胚胎的发育毒性,以斑马鱼为模式生物,观察不同质量浓度的短链氯化石蜡C10(50.2% Cl)暴露24,48,72和96 h后斑马鱼胚胎/幼鱼的死亡率、孵化率、畸形率和体长.结果表明,C10(50.2% Cl)在斑马鱼的早期发育阶段可引起一系列非致死效应和致死效应.高质量浓度(1000和10000μg/L)短链氯化石蜡可导致96 h斑马鱼胚胎死亡率显著升高(达100%),48 h抑制胚胎的孵化,并诱发一系列的发育畸形.C10(50.2% Cl)在斑马鱼幼鱼中引起的畸形表型主要包括脊柱弯曲,卵黄畸形,心包囊肿,尾部畸形和鱼鳔发育缺陷.低质量浓度组和高质量浓度组C10(50.2% Cl)均能够抑制斑马鱼幼鱼的生长速度,目前的环境质量浓度已具有一定程度的水生生态风险.

  14. 固相萃取-气相色谱-质谱法测定皮革制品中短链氯化石蜡%Determination of short chain chlorinated paraffins in leather products by solid phase extraction coupled with gas chromatography-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    张伟亚; 万昕; 李丽霞; 王成云; 金淑培; 邢钧

    2014-01-01

    短链氯化石蜡( SCCPs)是我国皮革加脂过程中常用的添加剂,但近年已被欧盟等列为禁止使用的持久性有机污染物。由于 SCCPs结构复杂,且皮革基质干扰严重,目前尚没有完善的皮革制品中 SCCPs 的标准检测方法。本文采用硅胶为固相萃取柱萃取,以正己烷-二氯甲烷(2∶1,v/v)为洗脱剂,使 SCCPs与皮革基质中的干扰组分完全分离,建立了用于测定皮革制品中 SCCPs 的固相萃取-气相色谱-质谱方法。该方法的回收率为90.47%~99.00%,检出限为0.069~0.110 mg/kg,相对标准偏差( RSD)为4.20%~6.69%。该方法适用于皮革中 SCCPs 的定性、定量分析。%The short chain chlorinated paraffins( SCCPs)are the additives frequently used in the leather production in China,but they have been put into the list of forbidden chemicals issued by European Union recently. In fact,there is not a commonly recognized method for the determination of the SCCPs in the leather products due to the serious matrix interferences from the leather products and the complex chemical structures of the SCCPs. A method of solid phase extraction coupled with gas chromatography-mass spectrometry ( SPE-GC-MS ) was established for the determination of the SCCPs in the leather products after the optimization of the SPE conditions. It was found that the interferences from the leather products were thor-oughly separated from the analyte of the SCCPs on a home-made solid phase extraction( SPE) column filled with silica packing while eluted with a mixed solvent of n-hexane-methylene chlo-ride(2∶1,v/v). With this method,the recoveries for the SCCPs spiked in the real leather sam-ples varied from 90. 47% to 99. 00% with the relative standard deviations( RSDs)less than 6. 7%,and the limits of detection( LODs)were between 0. 069 and 0. 110 mg/kg. This method is suitable for qualitative and quantitative analysis of SCCPs in the leather products.

  15. Assessing the Origins of Aliphatic Amines in the Murchison Meteorite from their Compound-Specific Carbon Isotopic Ratios and Enantiomeric Composition

    Science.gov (United States)

    Aponte, Jose; Dworkin, Jason; Elsila, Jamie E.

    2014-01-01

    The study of meteoritic organic compounds provides a unique window into the chemical inventory of the early Solar System and prebiotic chemistry that may have been important for the origin of life on Earth. Multiple families of organic compounds have been extracted from the Murchison meteorite, which is one of the most thoroughly studied carbonaceous chondrites. The amino acids extracted from Murchison have been extensively analyzed, including measurements of non-terrestrial stable isotopic ratios and discoveries of L-enantiomeric excesses for alpha-dialkyl amino acids, notably isovaline. However, although the isotopic signatures of bulk amine-containing fractions have been measured, the isotopic ratios and enantiomeric composition of individual aliphatic amines, compounds that are chemically related to amino acids, remain unknown. Here, we report a novel method for the extraction, separation, identification and quantitation of aliphatic monoamines extracted from the Murchison meteorite. Our results show a complete suite of structural isomers, with a larger concentration of methylamine and ethylamine and decreasing amine concentrations with increasing carbon number. The carbon isotopic compositions of fourteen meteoritic aliphatic monoamines were measured, with delta C-13 values ranging from +21% to +129%, showing a decrease in C-13 with increasing carbon number, a relationship that may be consistent with the chain elongation mechanism under kinetic control previously proposed for meteoritic amino acids. We also found the enantiomeric composition of sec-butylamine, a structural analog to isovaline, was racemic within error, while the isovaline extracted from the same Murchison piece showed an L-enantiomeric excess of 9.7; this result suggested that processes leading to enantiomeric excess in the amino acid did not affect the amine. We used these collective data to assess the primordial synthetic origins of these meteoritic aliphatic amines and their potential

  16. A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines.

    Science.gov (United States)

    Ohtsuka, Naoya; Okuno, Moriaki; Hoshino, Yujiro; Honda, Kiyoshi

    2016-10-14

    A variety of aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of a base is sufficient for the reaction, and a clean reaction in which only carbon dioxide is produced as a by-product. A self-propagating mechanism via an isocyanate intermediate is proposed and elementary reaction steps, namely, chain propagation reactions are supported by experiments.

  17. Estrogenic activity of alkylphenols, bisphenol S, and their chlorinated derivatives using a GFP expression system.

    Science.gov (United States)

    Kuruto-Niwa, Ryoko; Nozawa, Ryushi; Miyakoshi, Takashi; Shiozawa, Tatsushi; Terao, Yoshiyasu

    2005-01-01

    Alkylphenol ethoxylates, widely used non-ionic surfactants, are biodegraded into alkylphenols such as nonylphenol (NP) and t-octylphenol (OP), short-chain ethoxylates such as NP-monoethoxylate (NP1EO) and NP-diethoxylate (NP2EO), and alkylphenoxy carboxylic acids such as 4-t-octylphenoxyacetic acid (OP1EC). Bisphenol S (BPS) is more heat-stable and photo-resistant than bisphenol A (BPA), and therefore replaces BPA. These chemicals could be chlorinated during wastewater treatment. We synthesized these compounds and their chlorinated derivatives to estimate their estrogenic activities using a GFP expression system. The EC(50) ranking of NP-related compounds was NP > ClNP > diClNP > NP1EO > ClNP1EO > NP2EO. The estrogenic activity of OP1EC was 10 times less potent than parent OP. Furthermore, BPS showed comparable estrogenic activity with BPA. The EC(50) ranking of BPS-related compounds was BPA ≥ BPS > triClBPS > diClBPS > ClBPS. Other tested BPS derivatives had no estrogenic activity. Chlorination of the tested chemicals did not enhance their estrogenic activity, in contrast to certain chlorinated BPAs. Thus, our results demonstrated that chlorinated derivatives of NP, OP, and BPS, even if artificially produced during wastewater processing, were less estrogenic than their parent chemicals, known as endocrine disruptors.

  18. The molecular assembly of the ionic liquid/aliphatic carboxylic acid/aliphatic amine as effective and safety transdermal permeation enhancers.

    Science.gov (United States)

    Kubota, Koji; Shibata, Akira; Yamaguchi, Toshikazu

    2016-04-30

    In spite of numerous advantages, transdermal drug delivery systems are unfeasible for most drugs because of the barrier effect of the stratum corneum. Ionic liquids were recently used to enhance transdermal drug delivery by improving drug solubility. In the present study, safe and effective ionic liquids for transdermal absorption were obtained as salts generated by a neutralization reaction between highly biocompatible aliphatic carboxylic acids (octanoic acid or isostearic acid) and aliphatic amines (diisopropanolamine or triisopropanolamine) (Medrx Co., Ltd., 2009). The mechanism of skin permeability enhancement by ionic liquids was investigated by hydrophilic phenol red and hydrophobic tulobuterol. Further, the skin permeation enhancing effect was remarkably superior in the acid excess state rather than the neutralization state. Infrared absorption spectrum analysis confirmed that ionic liquids/aliphatic carboxylic acid/aliphatic amine are coexisting at all mixing states. In the acid excess state, ionic liquids interact with aliphatic carboxylic acids via hydrogen bonds. Thus, the skin permeation enhancing effect is not caused by the ionic liquid alone. The "liquid salt mixture," referred to as a complex of ingredients coexisting with ionic liquids, forms a molecular assembly incorporating hydrophilic drug. This molecular assembly was considered an effective and safety enhancer of transdermal drug permeation.

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

    Science.gov (United States)

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

    2016-03-15

    The seasonal assessment of anthropogenic activities in the Vaza Barris estuarine river system, located in the Sergipe state, northeastern Brazil, was performed using the aliphatic hydrocarbon distribution. The aliphatic hydrocarbon and isoprenoid (Pristane and Phytane) concentrations ranged between 0.19 μg g(-1) and 8.5 μg g(-1) of dry weight. Data were analyzed using Kruskal-Wallis test, with significance level set at p n-alkanes/n-C16, Low Molecular Weight/High Molecular Weight ratio (LMW/HMW) and Terrigenous to Aquatic Ratio (TAR) suggested biogenic input of aliphatic hydrocarbons for most samples, with significant contribution of higher plants.

  20. STRUCTURAL PHASE TRANSITION OF ALIPHATIC NYLONS VIEWED FROM THE WAXD/SAXS AND VIBRATIONAL SPECTRAL MEASUREMENTS AND MOLECULAR DYNAMICS CALCULATION

    Institute of Scientific and Technical Information of China (English)

    Kohji Tashiro

    2007-01-01

    The crystalline phase transition of aliphatic nylon 10/10 has been investigated on the basis of the simultaneous measurement of wide-angle and small-angle X-ray scatterings, the infrared spectral measurement and the molecular dynamics calculation. An interpretation of infrared spectra taken for a series of nylon samples and the corresponding model compounds was successfully made, allowing us to assign the infrared bands of the planar-zigzag methylene segments reasonably. As a result the methylene segmental parts of molecular chains were found to experience an order-to-disorder transition in the Brill transition region, where the intermolecular hydrogen bonds are kept alive although the bond strength becomes weaker at higher temperature. The small-angle X-ray scattering data revealed a slight change in lamellar stacking mode in the transition region. The crystal structure has been found to change more remarkably in the temperature region immediately below the melting point, where the conformationally disordered chains experienced drastic rotational and translational motions without any constraints by hydrogen bonds, and the lamellar thickness increased largely along the chain axis. These experimental results were reasonably reproduced by the molecular dynamics calculation performed at the various temperatures.

  1. Chlorination of Wastewater, Manual of Practice No. 4.

    Science.gov (United States)

    Water Pollution Control Federation, Washington, DC.

    This manual reviews chlorination practices in the treatment and disposal of wastes from the earliest known applications. The application of chlorination for various purposes is described but no attempt has been made to compare chlorination with other methods. Included are chapters on the development and practice of wastewater chlorination,…

  2. Electron affinity of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, L.M.; Pentecost, T.; Koppenol, W.H. (Louisiana State Univ., Baton Rouge (USA))

    1989-12-14

    The flowing afterglow technique was used to determine the electron affinity of chlorine dioxide. A value of 2.37 {plus minus} 0.10 eV was found by bracketing between the electron affinities of HS* and SF{sub 4} as a lower limit and that of NO{sub 2} as an upper limit. This value is in excellent agreement with 2.32 eV predicted from a simple thermodynamic cycle involving the reduction potential of the ClO{sub 2}/ClO{sub 2}{sup {minus}} couple and a Gibbs hydration energy identical with that of SO{sub 2}{sup {sm bullet}{minus}}.

  3. Antibacterial Activity of Long-Chain Fatty Alcohols against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Yoshihiro Inoue

    2007-02-01

    Full Text Available The antibacterial activity against Staphylococcus aureus of long-chain fatty alcohols was investigated, with a focus on normal alcohols. The antibacterial activity varied with the length of the aliphatic carbon chain and not with the water/octanol partition coefficient. 1-Nonanol, 1-decanol and 1-undecanol had bactericidal activity and membrane-damaging activity. 1-Dodecanol and 1-tridecanol had the highest antibacterial activity among the long-chain fatty alcohols tested, but had no membrane-damaging activity. Consequently, it appears that not only the antibacterial activity but also the mode of action of long-chain fatty alcohols might be determined by the length of the aliphatic carbon chain.

  4. Chemical tagging of chlorinated phenols for their facile detection and analysis by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Valdez, Carlos A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Leif, Roald N. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

    2015-03-22

    A derivatization method that employs diethyl (bromodifluoromethyl) phosphonate (DBDFP) to efficiently tag the endocrine disruptor pentachlorophenol (PCP) and other chlorinated phenols (CPs) along with their reliable detection and analysis by NMR is presented. The method accomplishes the efficient alkylation of the hydroxyl group in CPs with the difluoromethyl (CF2H) moiety in extremely rapid fashion (5 min), at room temperature and in an environmentally benign manner. The approach proved successful in difluoromethylating a panel of 18 chlorinated phenols, yielding derivatives that displayed unique 1H, 19F NMR spectra allowing for the clear discrimination between isomerically related CPs. Due to its biphasic nature, the derivatization can be applied to both aqueous and organic mixtures where the analysis of CPs is required. Furthermore, the methodology demonstrates that PCP along with other CPs can be selectively derivatized in the presence of other various aliphatic alcohols, underscoring the superiority of the approach over other general derivatization methods that indiscriminately modify all analytes in a given sample. The present work demonstrates the first application of NMR on the qualitative analysis of these highly toxic and environmentally persistent species.

  5. 大体积采样结合高分辨气相色谱-电子捕获负化学源-低分辨质谱法测定空气中的短链氯化石蜡%Determination of short-chain chlorinated paraffins in ambient air using high-volume sampling combined with high resolution gas chromatography-electron capture negative ion-low resolution mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    史蕾蒙; 高媛; 侯晓虹; 张海军; 张亦弛; 陈吉平

    2016-01-01

    建立了大体积采样结合高分辨气相色谱-电子捕获负化学源-低分辨质谱( HRGC-ECNI-LRMS)测定空气中短链氯化石蜡( SCCPs)的定量分析方法.联合使用酸化硅胶复合层析柱和碱性氧化铝层析柱净化处理空气样品中的 SCCPs,并对净化条件进行优化.使用该方法计算得到氯含量为58. 1%~63. 3%的 SCCPs系列标准储备溶液的总响应因子与氯含量线性相关,相关系数(R2)大于 0. 99.该方法的仪器检出限(S/N≥3)为 4. 2 pg,定量限(S/N≥10)为12 pg.SCCPs的方法检出限(MDL)为0. 34 ng/m3(n=7),实际样品加标回收率均达 80%以上.该方法灵敏度高、选择性好,能满足空气样品中 SCCPs的监测和分析需求.%An analytical method for quantifying short-chain chlorinated paraffins( SCCPs)in ambient air using high-volume sampling combined with high resolution gas chromatography-electron capture negative ion-low resolution mass spectrometry ( HRGC-ECNI-LRMS ) was developed. An acidified silica gel column and a basic alumina column were used to optimize the cleanup procedures. The results showed a good linearity(R2>0. 99)between the total response factors and the degree of chlorination of SCCPs in the content range of 58. 1%-63. 3%. The lim-its of detection( S/N≥3 ) and the limits of quantification( S/N≥10 ) were 4. 2 and 12 pg, respectively. The method detection limit( MDL)for SCCPs was 0. 34 ng/m 3( n=7). The recov-eries of SCCPs in air samples were in the range of 81. 9% to 94. 2%. It is demonstrated that the method is suitable for the quantitative analysis of SCCPs in air samples.

  6. Phosphate valorization by dry chlorination route

    OpenAIRE

    Kanari N.; Menad N.; Diot F.; Allain E.; Yvon J.

    2016-01-01

    International audience; This work deals with the extraction of phosphorus chlorinated compounds from phosphate materials using chlorination with gaseous chlorine. An industrial sample of dicalcium phosphate dihydrate, after transformation into calcium pyrophosphate (Ca 2 P 2 O 7), is subjected to reactions with Cl 2 +CO+N 2 and Cl 2 +C+N 2 at temperatures ranging from 625 to 950 °C using boat experiments. Gathering results of the thermodynamic predictions and TG/DT analysis with those of SEM ...

  7. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    OpenAIRE

    Taylor, G. R.; Butler, M.

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the ...

  8. Shape memory polymers based on uniform aliphatic urethane networks

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-01-19

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

  9. Electrospun aliphatic polycarbonates as tailored tissue scaffold materials.

    Science.gov (United States)

    Welle, Alexander; Kröger, Mario; Döring, Manfred; Niederer, Kerstin; Pindel, Elvira; Chronakis, Ioannis S

    2007-04-01

    Two different aliphatic polycarbonates were synthesised from CO(2) and the respective epoxides. Poly(propyl carbonate) (PPC) was prepared by heterogeneous catalysis with zinc glutarate. Poly(cyclohexyl carbonate) (PCHC) was prepared via living copolymerisation homogeneously catalysed by a 3-amino-2-cyanoimidoacrylate zinc acetate complex and subjected to electrospinning. The obtained nanofibres had a well-defined morphology free of beads along the fibres and with slightly porous structures on their surface. Subsequently, low-power deep UV irradiations, previously applied for photochemical surface modifications of two-dimensional and three-dimensional scaffolds from biostable polymers, were performed. Here, an effect on surface and bulk properties of PPC nanofibres was observed. Surface modifications of both polymers affected plasma protein adsorption. Photochemical bulk modifications observed for the first time on PPC nanofibres are indicating the possibility of spatial control of biodegradation rates, hence allow for control of the progression of host/implant interactions in vivo. In particular PPC was used for cell culture of L929 fibroblasts and primary rat hepatocytes. Even delicate primary cells showed good adhesion to the scaffolds and high viability.

  10. Enhanced crystallization of poly (lactic acid) through reactive aliphatic bisamide

    Science.gov (United States)

    Nanthananon, P.; Seadan, M.; Pivsa-Art, S.; Suttiruengwong, S.

    2015-07-01

    The poor crystallization rate of poly (lactic acid) (PLA) is a major drawback in terms of controlling the properties of final products. To overcome this, a nucleating agent is normally applied. In this work, the aliphatic bisamide, N, N'-(1,3-propylene) bis(10-undecenamide) (PBU), having reactive functional groups is used as a crystallization promoter for PLA by adding PBU in various concentration (0.1-0.7 wt%) into PLA together with peroxide via reactive melt blending. The conventional ethylene bis-stearamide(EBS) is used for a comparison. The extruded samples are characterized for gel content and FT-IR spectroscopy. The crystallization behaviour and rate, and spherulites morphology are investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), respectively. It is found that the addition of PBU into PLA results in the dramatic increase in crystallinity and crystallization rate of PLA compared with neat PLA and PLA added EBS. The crystallinity increases to 24.9-28.3% higher than neat PLA under even cooling rate of 7°C/min. The addition of 0.7 wt% PBU shows the fastest crystallization rate with t1/2 value isothermally crystallized at 130°C of only 6 min. POM images indicate the increase in the nucleation density and very fine spherulitesof PLA added PBU, promoting the fast crystallization.

  11. Liquid-crystalline aromatic-aliphatic copolyester bioresorbable polymers.

    Science.gov (United States)

    de Oca, Horacio Montes; Wilson, Joanne E; Penrose, Andrew; Langton, David M; Dagger, Anthony C; Anderson, Melissa; Farrar, David F; Lovell, Christopher S; Ries, Michael E; Ward, Ian M; Wilson, Andrew D; Cowling, Stephen J; Saez, Isabel M; Goodby, John W

    2010-10-01

    The synthesis and characterisation of a series of liquid-crystalline aromatic-aliphatic copolyesters are presented. Differential scanning calorimetry showed these polymers have a glass transition temperature in the range 72 degrees C-116 degrees C. Polarised optical microscopy showed each polymer exhibits a nematic mesophase on heating to the molten state at temperatures below 165 degrees C. Melt processing is demonstrated by the production of injection moulded and compression moulded specimens with Young's modulus of 5.7 +/- 0.3 GPa and 2.3 +/- 0.3 GPa, respectively. Wide-angle X-ray scattering data showed molecular orientation is responsible for the increase of mechanical properties along the injection direction. Degradation studies in the temperature range 37 degrees C-80 degrees C are presented for one polymer of this series and a kinetic constant of 0.002 days(-1) is obtained at 37 degrees C assuming a first order reaction. The activation energy (83.4 kJ mol(-1)) is obtained following the Arrhenius analysis of degradation, showing degradation of this material is less temperature sensitive compared with other commercially available biodegradable polyesters. In vitro and in vivo biocompatibility data are presented and it is shown the unique combination of degradative, mechanical and biological properties of these polymers may represent in the future an alternative for medical device manufacturers.

  12. Fully Biobased Unsaturated Aliphatic Polyesters from Renewable Resources : Enzymatic Synthesis, Characterization, and Properties

    NARCIS (Netherlands)

    Jiang, Yi; Alberda van Ekenstein, Gerhard; Woortman, Albert J. J.; Loos, Katja

    2014-01-01

    Fully biobased saturated and unsaturated aliphatic polyesters and oligoesters are successfully prepared by Candida antarctica lipase B (CALB)-catalyzed polycondensations of succinate, itaconate, and 1,4-butanediol. The effects of monomer substrates and polymerization methods on enzymatic polycondens

  13. Insights into support wettability in tuning catalytic performance in the oxidation of aliphatic alcohols to acids.

    Science.gov (United States)

    Wang, Min; Wang, Feng; Ma, Jiping; Chen, Chen; Shi, Song; Xu, Jie

    2013-07-28

    A superhydrophobic catalyst was prepared by immobilizing Pt nanoparticles on superhydrophobic organic-inorganic hybrid silicas, which showed high activity and selectivity in the oxidation of aliphatic alcohols to carboxylic acids.

  14. Thermally reversible thermoset materials based on the chemical modification of alternating aliphatic polyketones

    NARCIS (Netherlands)

    Araya Hermosilla, Rodrigo Andrés

    2016-01-01

    This thesis focused on the synthesis and characterization of different kinds of reversible thermosets and thermoset nanocomposite materials by using alternating aliphatic polyketone (PK) as raw material. Fundamental knowledge was generated regarding the molecular design of new polymers via chemical

  15. Behavior of chlorine during coal pyrolysis

    Science.gov (United States)

    Shao, D.; Hutchinson, E.J.; Cao, H.; Pan, W.-P.; Chou, C.-L.

    1994-01-01

    The behavior of chlorine in Illinois coals during pyrolysis was evaluated by combined thermo-gravimetry-Fourier transform infrared spectroscopy-ion chromatography (TG-FTIR-IC) techniques. It was found that more than 90% of chlorine in Illinois coals (IBC-103, 105, 106, and 109) was liberated as HCl gas during pyrolysis from 300 to 600??C, with the rate reaching a maximum at 440 ??C. Similarity of the HCl and NH3 release profiles during pyrolysis of IBC-109 supports the hypothesis that the chlorine in coal may be associated with nitrogen and the chlorine is probably bonded to the basic nitrogen sites on the inner walls of coal micropores. ?? 1994 American Chemical Society.

  16. Chlorine Salts at the Phoenix Landing Site

    Science.gov (United States)

    Hanley, J.; Horgan, B.

    2016-09-01

    Although chlorine salts (perchlorates, chlorides) are known to exist at the Phoenix landing site, their distribution and type have not been positively identified yet. We look for these salts through a novel NIR remote sensing technique.

  17. Silver-Catalyzed Decarboxylative Allylation of Aliphatic Carboxylic Acids in Aqueous Solution.

    Science.gov (United States)

    Cui, Lei; Chen, He; Liu, Chao; Li, Chaozhong

    2016-05-06

    Direct decarboxylative radical allylation of aliphatic carboxylic acids is described. With K2S2O8 as the oxidant and AgNO3 as the catalyst, the reactions of aliphatic carboxylic acids with allyl sulfones in aqueous CH3CN solution gave the corresponding alkenes in satisfactory yields under mild conditions. This site-specific allylation method is applicable to all primary, secondary, and tertiary alkyl acids and exhibits wide functional group compatibility.

  18. Thermally reversible thermoset materials based on the chemical modification of alternating aliphatic polyketones

    OpenAIRE

    Araya Hermosilla, Rodrigo Andrés

    2016-01-01

    This thesis focused on the synthesis and characterization of different kinds of reversible thermosets and thermoset nanocomposite materials by using alternating aliphatic polyketone (PK) as raw material. Fundamental knowledge was generated regarding the molecular design of new polymers via chemical modification of PK with aliphatic and aromatic amine compounds. The resulting thermally reversible thermoset systems were investigated to outline the benefits for the synergistic cooperation betwee...

  19. Falling chains

    Science.gov (United States)

    Wong, Chun Wa; Yasui, Kosuke

    2006-06-01

    The one-dimensional fall of a folded chain with one end suspended from a rigid support and a chain falling from a resting heap on a table is studied. Because their Lagrangians contain no explicit time dependence, the falling chains are conservative systems. Their equations of motion are shown to contain a term that enforces energy conservation when masses are transferred between subchains. We show that Cayley's 1857 energy nonconserving solution for a chain falling from a resting heap is incorrect because it neglects the energy gained when a link leaves a subchain. The maximum chain tension measured by Calkin and March for the falling folded chain is given a simple if rough interpretation. Other aspects of the falling folded chain are briefly discussed.

  20. Hydrochloric acid recycling from chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Sowieja, D. [Sulzer Escher Wyss GmbH, Ravensburg (Germany); Schaub, M. [Sulzer Chemtech Ltd., Winterthur (Switzerland)

    1993-12-31

    Chlorinated hydrocarbons present a major ecological hazard since most of them are only poorly biodegradable. Incineration is an economical process for their destruction, however the usually recovered sodium or calcium chlorides do not present a value and their disposal may even be very costly. Recovery of hydrochloric acid may therefore present an economical solution, mainly were large quantities of highly chlorinated compounds can be processed (author) 6 refs., 4 figs., 1 tab.

  1. Modeling Trihalomethane Formation Potential from Wastewater Chlorination

    Science.gov (United States)

    1994-09-01

    chemically with each other, and with living organisms, particularly bacteria ( Manahan , 1991:435). To ensure effective disinfection, to meet the CWA...halogens are strong oxidants and are highly reactive ( Manahan , 1991:504). Chlorine is never found uncombined in nature, it exists only as the...HOCI) according to the following reaction: Cl2 (gas) + H20 =• HOC1 + H+ + Cl The hydrogen is oxidized and the chlorine gas is reduced ( Manahan , 1991

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2007-05-01

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

  4. Chlorinated drinking water for lightweight laying hens

    Directory of Open Access Journals (Sweden)

    A.F. Schneider

    Full Text Available ABSTRACT The study aimed to evaluate the effect of different levels of chlorine in drinking water of laying hens on zootechnical performance, eggs shell quality, hemogasometry levels and calcium content in tibia. 144 Hy-Line laying hens, 61 weeks old, were used distributed in 24 metabolism cages. They were subjected to water diets, for a period of 28 days, using sodium hypochlorite as a chlorine source in order to obtain the following concentrations: 5ppm (control, 20ppm, 50ppm, and 100ppm. Their performance was evaluated through water consumption, feed intake, egg production and weight, egg mass, feed conversion. Shell quality was measured by specific gravity. At the end of the experiment, arterial blood was collected for blood gas level assessment and a poultry of each replicate was sacrificed to obtain tibia and calcium content measurement. There was a water consumption reduction from 20ppm of chlorine and feed intake reduction in poultry receiving water with 100ppm of chlorine. The regression analysis showed that the higher the level of chlorine in water, the higher the reduction in consumption. There were no differences in egg production and weight, egg mass, feed conversion, specific gravity, tibia calcium content, and hemogasometry levels (hydrogenionic potential, carbon dioxide partial pressure, oxygen partial pressure, sodium, potassium, chloride, bicarbonate, carbon dioxide total concentration, anion gap and oxygen saturation. The use of levels above 5ppm of chlorine is not recommended in the water of lightweight laying hens.

  5. Two Novel Flavin-Containing Monooxygenases Involved in Biosynthesis of Aliphatic Glucosinolates

    Directory of Open Access Journals (Sweden)

    Wenwen Kong

    2016-08-01

    Full Text Available Glucosinolates (GSLs, a class of secondary metabolites from cruciferous plants, are derived from amino acids and have diverse biological activities, such as in biotic defense, depending on their side chain modification. The first structural modification step in the synthesis of aliphatic (methionine-derived GSLs—S-oxygenation of methylthioalkyl GSLs to methylsulfinylalkyl GSLs—was found to be catalyzed by five flavin-containing monooxygenases (FMOs, FMOGS-OX1-5. Here, we report two additional FMOGS-OX enzymes, FMOGS-OX6 and FMOGS-OX7, encoded by At1g12130 and At1g12160, respectively. The overexpression of both FMOGS-OX6 and FMOGS-OX7 decreased the ratio of MT GSL to the sum of MT and MS GSL, suggesting that the introduction of the two genes converted MT GSL into MS GSL. Analysis of expression pattern revealed that the spatial expression of the two genes is quite similar and partially overlapped with the other FMOGS-OX genes, which are primarily expressed in vascular tissue. We further analyzed the responsive expression pattern of all the seven FMOGS-OX genes to exogenous treatment with abscisic acid (ABA, 1-aminocyclopropane-1-carboxylic acid (ACC, jasmonic acid (JA, salicylic acid (SA, indole-3-acetic acid (IAA, and low and high temperatures. Although these genes showed same tendency toward the changing stimulus, the sensitivity of each gene was quite different. The variety in spatial expression among the FMOGS-OX genes while responding to environmental stimulus indicated a complex and finely tuned regulation of GSL modifications. Identification of these two novel FMOGS-OX enzymes will enhance the understanding of GSL modifications and the importance of evolution of these duplicated genes.

  6. Forward targeting of Toxoplasma gondii proproteins to the micronemes involves conserved aliphatic amino acids.

    Science.gov (United States)

    Gaji, Rajshekhar Y; Flammer, Halley P; Carruthers, Vern B

    2011-07-01

    Like other apicomplexan parasites, Toxoplasma gondii actively invades host cells using a combination of secretory proteins and an acto-myosin motor system. Micronemes are the first set of proteins secreted during invasion that play an essential role in host cell entry. Many microneme proteins (MICs) function in protein complexes, and each complex contains at least one protein that displays a cleavable propeptide. Although MIC propeptides have been implicated in forward targeting to micronemes, the specific amino acids involved have not been identified. It was also not known if the propeptide has a general function in MICs trafficking in T. gondii and other apicomplexans. Here we show that propeptide domains are extensively interchangeable between T. gondii MICs and also with that of Eimeria tenella MIC5 (EtMIC5), suggesting a common mechanism of function. We also performed N-terminal deletion and mutational analysis of M2AP and MIC5 propeptides to show that a valine at position +3 (relative to signal peptidase cleavage) of proM2AP and a leucine at position +1 of proMIC5 are crucial for targeting to micronemes. Valine and leucine are closely related amino acids with similar side chains, implying a similar mode of function, a notion that was confirmed by correct trafficking of TgM2AP-V/L and TgMIC5-L/V substitution mutants. Propeptides of AMA1, MIC3 and EtMIC5 have valine or leucine at or near the N-termini and mutagenesis of these conserved residues validated their role in microneme trafficking. Collectively, our findings suggest that discrete, aliphatic residues at the extreme N-termini of proMICs facilitate trafficking to the micronemes.

  7. Chlorine dioxide reaction with selected amino acids in water

    Energy Technology Data Exchange (ETDEWEB)

    Navalon, Sergio; Alvaro, Mercedes [Department of Chemistry, Universidad Politecnica de Valencia, Camino de Vera S/N, 46022 Valencia (Spain); Garcia, Hermenegildo, E-mail: hgarcia@qim.upv.es [Department of Chemistry, Universidad Politecnica de Valencia, Camino de Vera S/N, 46022 Valencia (Spain)

    2009-05-30

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO{sub 2} with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO{sub 2} were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO{sub 2} creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO{sub 2} with ubiquitous amino acids present in natural waters.

  8. Modification with alkyl chains and the influence on thermal and mechanical properties of aromatic hyperbranched polyesters

    NARCIS (Netherlands)

    Schmaljohann, Dirk; Häußler, Liane; Pötschke, Petra; Voit, Brigitte I.; Loontjens, Ton J.A.

    2000-01-01

    All-aromatic hyperbranched polyesters with hydroxy endgroups were functionalized with aliphatic n-alkyl carboxylic acids. The length of the n-alkyl chain as well as the degree of modification were varied and the resulting, partially amphiphilic polymers were characterized by differential scanning ca

  9. Kinetics and mechanism of styrene epoxidation by chlorite: role of chlorine dioxide.

    Science.gov (United States)

    Leigh, Jessica K; Rajput, Jonathan; Richardson, David E

    2014-07-07

    An investigation of the kinetics and mechanism for epoxidation of styrene and para-substituted styrenes by chlorite at 25 °C in the pH range of 5-6 is described. The proposed mechanism in water and water/acetonitrile includes seven oxidation states of chlorine (-I, 0, I, II, III, IV, and V) to account for the observed kinetics and product distributions. The model provides an unusually detailed quantitative mechanism for the complex reactions that occur in mixtures of chlorine species and organic substrates, particularly when the strong oxidant chlorite is employed. Kinetic control of the reaction is achieved by the addition of chlorine dioxide to the reaction mixture, thereby eliminating a substantial induction period observed when chlorite is used alone. The epoxidation agent is identified as chlorine dioxide, which is continually formed by the reaction of chlorite with hypochlorous acid that results from ClO produced by the epoxidation reaction. The overall stoichiometry is the result of two competing chain reactions in which the reactive intermediate ClO reacts with either chlorine dioxide or chlorite ion to produce hypochlorous acid and chlorate or chloride, respectively. At high chlorite ion concentrations, HOCl is rapidly eliminated by reaction with chlorite, minimizing side reactions between HOCl and Cl2 with the starting material. Epoxide selectivity (>90% under optimal conditions) is accurately predicted by the kinetic model. The model rate constant for direct reaction of styrene with ClO2(aq) to produce epoxide is (1.16 ± 0.07) × 10(-2) M(-1) s(-1) for 60:40 water/acetonitrile with 0.20 M acetate buffer. Rate constants for para substituted styrenes (R = -SO3(-), -OMe, -Me, -Cl, -H, and -NO2) with ClO2 were determined. The results support the radical addition/elimination mechanism originally proposed by Kolar and Lindgren to account for the formation of styrene oxide in the reaction of styrene with chlorine dioxide.

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

    Science.gov (United States)

    Hillmyer, Marc A; Tolman, William B

    2014-08-19

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

  11. A new kind of Molotov? Gasoline-pool chlorinator mixtures.

    Science.gov (United States)

    Hutches, Katherine; Lord, James

    2012-07-01

    This paper investigates the reaction between pool chlorinators and gasoline. In particular, the propensity for self-ignition and the resulting chemical products were studied. An organic pool chlorinator was combined with gasoline in varying proportions in an attempt to form a hypergolic mixture. None of the combinations resulted in self-ignition, but larger quantities of chlorinator produced vigorous light-colored smoke and a solid mass containing isocyanuric acid and copper chloride. Additionally, the chlorinating abilities of different commercially available pool chlorinators were explored. When Ca(ClO)(2) and sodium dichloro-s-triazinetrione-based chlorinators were used, the presence of gasoline was still visible after 10 days, despite limited chlorination. The trichloro-s-triazinetrione-based chlorinator, however, caused efficient chlorination of the C(2)- and C(3)-alkylbenzenes, making gasoline no longer identifiable.

  12. Maxillofacial prostheses of chlorinated polyethylene.

    Science.gov (United States)

    May, P D

    1978-05-01

    There is clearly a need for maxillofacial prosthetic materials with improved properties. The chlorinated polyethylenes are thermoplastic elastomers which have particularly promising properties, and were used by us to prepare improved maxillofacial prostheses. Suitable CPE resins were compounded with other polymers and with pigments on a heated rubber mill to form thin sheets in a variety of shades. These were heated at 190 degrees C for 10 min and placed between heated linotype mold halves. The prosthesis was formed in a hand press. Sometimes heating and pressing were repeated. After cooling in water, the prosthesis was removed and hand-shaded with oil-soluble dyes. Physical properties were evaluated using standard techniques; skin irritation studies were conducted by 14-day insult patch tests on rabbits. Clinical evaluations were conducted on human volunteers. Parallel evaluations were conducted on commerically available materials for comparison. The CPE was superior to all of the three commerical materials in most properties, and comparable to the better of the three in the remaining properties. On balance, CPE was significantly superior. Early results indicate that the materials and techniques required are easily handled in the dental lab and that the final prosthesis has excellent aesthetic and patient acceptability.

  13. Chlorine Abundances in Cool Stars

    CERN Document Server

    Maas, Z G; Hinkle, K

    2016-01-01

    Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\\mu$m. The high resolution L-band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4m telescope. The average [$^{35}$Cl/Fe] abundance in stars with --0.72$<$[Fe/H]$<$0.20 is [$^{35}$Cl/Fe]=(--0.10$\\pm$0.15) dex. The mean difference between the [$^{35}$Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16$\\pm$0.15) dex. The [$^{35}$Cl/Ca] ratio has an offset of $\\sim$0.35 dex above model predictions suggesting chemical evolution models are under producing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and \\ion{H}{2} regions. In one star where both H$^{35}$Cl a...

  14. Interaction of gaseous aromatic and aliphatic compounds in thermophilic biofilters.

    Science.gov (United States)

    Hu, Qing-yuan; Wang, Can

    2015-12-30

    Two thermophilic biofilters were applied in treating a mixture of gaseous aromatic (benzene) and aliphatic compounds (hexane) to evaluate the interaction of the compounds. The performance of the biofilters was investigated in terms of removal efficiencies, elimination capacity, kinetic analysis, interaction indices, and microbial metabolic characteristics. Results showed that the removal performance of benzene was unaffected by the addition of hexane. The removal efficiencies of benzene were maintained at approximately 80% and the biodegradation rate constant was maintained at 120 h(-1). However, the removal efficiencies of hexane decreased significantly from 60% to 20% and the biodegradation rate constant exhibited a distinct decrease from 93.59 h(-1) to 56.32 h(-1). The interaction index of benzene with the addition of hexane was -0.029, which indicated that hexane had little effect on the degradation of benzene. By contrast, the interaction index of hexane by benzene was -0.557, which showed that benzene inhibited the degradation of hexane significantly. Similar conclusions were obtained about the substrate utilization. Moreover, the utilization degree of carbon sources and the microbial metabolic activities in the biofilter treating hexane were significantly improved with the addition of benzene, whereas the addition of hexane had a slight effect on the microbial communities in the biofilter treating benzene. Conclusions could be obtained that when mixtures of benzene and hexane were treated using biofilters, the degradation of benzene, which was more easily degradable, was dominant and unaffected; whereas the degradation of hexane, which was less easily degradable, was inhibited because of the changing of microbes.

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

    Science.gov (United States)

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

    2014-12-01

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

  16. Secondary aerosol formation from atmospheric reactions of aliphatic amines

    Directory of Open Access Journals (Sweden)

    S. M. Murphy

    2007-01-01

    Full Text Available Although aliphatic amines have been detected in both urban and rural atmospheric aerosols, little is known about the chemistry leading to particle formation or the potential aerosol yields from reactions of gas-phase amines. We present here the first systematic study of aerosol formation from the atmospheric reactions of amines. Based on laboratory chamber experiments and theoretical calculations, we evaluate aerosol formation from reaction of OH, ozone, and nitric acid with trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and ethanolamine. Entropies of formation for alkylammonium nitrate salts are estimated by molecular dynamics calculations enabling us to estimate equilibrium constants for the reactions of amines with nitric acid. Though subject to significant uncertainty, the calculated dissociation equilibrium constant for diethylammonium nitrate is found to be sufficiently small to allow for its atmospheric formation, even in the presence of ammonia which competes for available nitric acid. Experimental chamber studies indicate that the dissociation equilibrium constant for triethylammonium nitrate is of the same order of magnitude as that for ammonium nitrate. All amines studied form aerosol when photooxidized in the presence of NOx with the majority of the aerosol mass present at the peak of aerosol growth consisting of aminium (R3NH+ nitrate salts, which repartition back to the gas phase as the parent amine is consumed. Only the two tertiary amines studied, trimethylamine and triethylamine, are found to form significant non-salt organic aerosol when oxidized by OH or ozone; calculated organic mass yields for the experiments conducted are similar for ozonolysis (15% and 5% respectively and photooxidation (23% and 8% respectively. The non-salt organic aerosol formed appears to be more stable than the nitrate salts and does not quickly repartition back to the gas phase.

  17. Secondary aerosol formation from atmospheric reactions of aliphatic amines

    Directory of Open Access Journals (Sweden)

    S. M. Murphy

    2007-01-01

    Full Text Available Although aliphatic amines have been detected in both urban and rural atmospheric aerosols, little is known about the chemistry leading to particle formation or the potential aerosol yields from reactions of gas-phase amines. We present here the first systematic study of aerosol formation from the atmospheric reactions of amines. Based on laboratory chamber experiments and theoretical calculations, we evaluate aerosol formation from reaction of OH, ozone, and nitric acid with trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and ethanolamine. Entropies of formation for alkylammonium nitrate salts are estimated by molecular dynamics calculations enabling us to estimate equilibrium constants for the reactions of amines with nitric acid. Though subject to significant uncertainty, the calculated dissociation equilibrium constant for diethylammonium nitrate is found to be sufficiently small to allow for its atmospheric formation, even in the presence of ammonia which competes for available nitric acid. Experimental chamber studies indicate that the dissociation equilibrium constant for triethylammonium nitrate is of the same order of magnitude as that for ammonium nitrate. All amines studied form aerosol when photooxidized in the presence of NOx with the majority of the aerosol mass present at the peak of aerosol growth consisting of aminium (R3NH+ nitrate salts, which repartition back to the gas phase as the parent amine is consumed. Only the two tertiary amines studied, trimethylamine and triethylamine, are found to form significant non-salt organic aerosol when oxidized by OH or ozone; calculated organic mass yields for the experiments conducted are similar for ozonolysis (15% and 5% respectively and photooxidation (23% and 8% respectively. The non-salt organic aerosol formed appears to be more stable than the nitrate salts and does not quickly repartition back to the gas phase.

  18. Vibrational and photoionization spectroscopy of biomolecules: aliphatic amino acid structures.

    Science.gov (United States)

    Hu, Yongjun; Bernstein, Elliot R

    2008-04-28

    The aliphatic amino acids glycine, valine, leucine, and isoleucine are thermally placed into the gas phase and expanded into a vacuum system for access by time of flight mass spectroscopy and infrared (IR) spectroscopy in the energy range of 2500-4000 cm(-1) (CH, NH, OH, and stretching vibrations). The isolated neutral amino acids are ionized by a single photon of 10.5 eV energy (118 nm), which exceeds by less than 2 eV their reported ionization thresholds. As has been reported for many hydrogen bonded acid-base systems (e.g., water, ammonia, alcohol, acid clusters, and acid molecules), the amino acids undergo a structural rearrangement in the ion state (e.g., in simplest form, a proton transfer) that imparts sufficient excess vibrational energy to the ion to completely fragment it. No parent ions are observed. If the neutral ground state amino acids are exposed to IR radiation prior to ionization, an IR spectrum of the individual isomers for each amino acid can be determined by observation of the ion intensity of the different fragment mass channels. Both the IR spectrum and fragmentation patterns for individual isomers can be qualitatively identified and related to a particular isomer in each instance. Thus, each fragment ion detected presents an IR spectrum of its particular parent amino acid isomer. In some instances, the absorption of IR radiation by the neutral amino acid parent isomer increases a particular fragmentation mass channel intensity, while other fragmentation mass channel intensities decrease. This phenomenon can be rationalized by considering that with added energy in the molecule, the fragmentation channel populations can be modulated by the added vibrational energy in the rearranged ions. This observation also suggests that the IR absorption does not induce isomerization in the ground electronic state of these amino acids. These data are consistent with theoretical predictions for isolated amino acid secondary structures and can be related to

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

    Science.gov (United States)

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

    2004-06-11

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

  20. Reactions of polynuclear aromatic hydrocarbons with chlorine and chlorine dioxide in coal tar lined pipes

    Energy Technology Data Exchange (ETDEWEB)

    Merkel, T.; Maier, M.; Sacher, F.; Maier, D. [University of Karlsruhe, Karlsruhe (Germany). Engler Bunte Institut

    1997-12-31

    In the presence of disinfectants, PAH are remobilised from the coal tar lining of water distribution mains. Reactions of the PAH with chlorine and chlorine dioxide can lead to chlorinated PAH that might show higher mutagenic effects that the parent PAH. Detection limits in the lower nanogram-per-litre level for the determination of PAH and chlorinated PAH were achieved by using solid phase micro extraction and a gas chromatographic mass spectrometric device. Thus, the reactions of four PAH (anthracene, fluoranthene, fluorene and phenanthrene) with chlorine and chlorine dioxide under conditions and at concentrations of common practice in the drinking water distribution system could be investigated. In batch experiments with demineralised and drinking water at pH 7, the concentrations of fluoranthene, fluorene and phenanthrene remained constant, whereas anthracene reacted quantitatively with both disinfectants. The reaction of anthracene followed by pseudo-first order kinetics. In these reactions no chlorinated products could be detected, only monohydroxyanthracene and anthraquinone were identified. The toxic effect of a set of chlorinated and oxidised PAH was also examined.

  1. Bromate ion formation in dark chlorination and ultraviolet/chlorination processes for bromide-containing water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Bormate (BrO3-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions,particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 μg/L). UV irradiation enhanced the decay of free chlorine, and,simultaneously, 6.6%-32% of Br- was oxidized to BrO3-. And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.

  2. Clinical evaluation of chlorine dioxide for disinfection of dental instruments.

    Science.gov (United States)

    Watamoto, Takao; Egusa, Hiroshi; Sawase, Takashi; Yatani, Hirofumi

    2013-01-01

    This study aimed to clinically evaluate the disinfection efficacy of chlorine dioxide (ClO2) for used dental instruments. An imprint culture technique demonstrated that ultrasonic cleaning of intraorally applied dental mirrors in 0.02% ClO2 for 10 minutes resulted in compete removal of microorganisms for 10 subjects. Hepatitis C virus (HCV) RNA was detected by real-time polymerase chain reaction on periodontal curettes after subgingival scaling in four HCV-infected patients and was completely removed by the same treatment procedure. Therefore, the combination of ultrasonic cleaning with ClO2 may provide an alternative to toxic disinfectants, such as glutaraldehyde and sodium hypochlorite, for disinfecting dental instruments.

  3. Unwrapping Chains

    CERN Document Server

    Cambou, A D; Hamm, E; Hanna, J A; Menon, N; Santangelo, C D; Walsh, L

    2012-01-01

    A loop of chain can move along its own tangents, maintaining a steady shape. An open-ended chain undergoing a nontrivial motion must change its shape. One consequence is that chains pulled around objects will fail to follow the contours of the objects, unwrapping themselves instead. This short note accompanies a fluid dynamics video submission (83068) to the APS DFD Gallery of Fluid Motion 2012.

  4. Falling chains

    CERN Document Server

    Wong, C W; Wong, Chun Wa; Yasui, Kosuke

    2006-01-01

    The one-dimensional falling motion of a bungee chain suspended from a rigid support and of a chain falling from a resting heap on a table is studied. Their Lagrangians are found to contain no explicit time dependence. As a result, these falling chains are conservative systems. Each of their Lagrange's equations of motion is shown to contain a term that enforces energy conservation when masses are transferred between subchains. We show in particular that Cayley's 1857 energy nonconserving solution for a chain falling from a resting heap is incorrect because it neglects the energy gained when the transferred link is emitted by the emitting subchain. The maximum chain tension measured by Calkin and March for the falling bungee chain is given a simple if rough interpretation. In the simplified one-dimensional treatment, the kinetic energy of the center of mass of the falling bungee chain is found to be converted by the chain tension at the rigid support into the internal kinetic energy of the chain. However, as t...

  5. Chlorine dioxide treatment for zebra mussel control

    Energy Technology Data Exchange (ETDEWEB)

    Rybarik, D. [Dairyland Power Cooperative, La Crosse, WI (United States); Byron, J. [Nalco Chemical Company, Naperville, IL (United States); Germer, M. [Rio Linda Chemical Company, Sacramento, CA (United States)

    1995-06-01

    Chlorine is recognized and commonly used biocide for power plant cooling water and service water treatment programs, including the control of zebra mussels. Chlorine dioxide has recently become a popular method of zebra mussel control because of its economy, safety, environmental acceptability, and effectiveness when compared to other mussel control methods. This control technique was recently demonstrated at Dairyland Power Cooperative`s Alma Generating Station on the east bank of the upper Mississippi River in Alma, Wisconsin. The project was assisted with EPRI Tailored Collaboration Program funds. The Dairyland Power Alam Generating Station consists of five generating units that utilize raw, untreated Mississippi River water for condenser, circulating, and service water supplies. The first units were built in 1947, with the final and largest unit being completed in 1960. Total station generating capacity is 200 MW. Because of recent increases in the zebra mussel density at the station intake, Dairyland Power selected the team of Nalco and Rio Linda to perform a chlorine dioxide treatment of the station`s new water systems to eradicate and control the mussels before their presence created operational difficulties. This paper will present the results of the treatment including treatment theory, design and construction of the treatment system, the method of chlorine dioxide generation, treatment concentration, analytical methods o monitoring chlorine dioxide generation, residuals and trihalomethane (THM) concentrations, protocol for monitoring treatment mortality, and the effects of chlorine dioxide and detoxification on other water chemistry parameters and equipment materials. The goal of this paper is to inform and assist users with establishing consistent and uniform practices for safely utilizing and monitoring chlorine dioxide in the eradication and control of zebra mussels.

  6. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine

    Institute of Scientific and Technical Information of China (English)

    Meiquan Cai; Liqiu Zhang; Fei Qi; Li Feng

    2013-01-01

    Owing to its low cost,free chlorine is one of the most common disinfectants for wastewater and drinking water treatment.However,the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades.Antipyrine (ANT),an anti-inflammatory analgesic,has been frequently detected in the aquatic environment.In this work.the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments.The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L,free chlorine dosage from 0.30 to 1.31 mg/L,and pH from 1.5 to 9.0.The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry.The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L,ANT 0.5 mg/L,pH 7.0).Higher oxidant dosage,lower ANT initial concentration and low pH favor the ANT removal.The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-l,2-dihydro1,5-dimethyl-2-phenyl-3H-pyrazol-3-one),which can be further chlorinated by free chlorine.In addition,the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  7. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine.

    Science.gov (United States)

    Cai, Meiquan; Zhang, Liqiu; Qi, Fei; Feng, Li

    2013-01-01

    Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  8. 脂肪族含氧有机物沸点的定量构效关系%Quantitative structure-property relationship of normal boiling point of aliphatic oxygen-containing organic compounds

    Institute of Scientific and Technical Information of China (English)

    刘万强; 曹晨忠

    2012-01-01

    The descriptors of polarizability effect index (PEI),the number of effective carbon (Nc,e(f)> the differences in PEI and Nc,eff between the branching chain and straight chain isomers,SPEI and δ Nc,eff,are derived from molecular structure. The quantitative structure-property relationships (QSPRs) between these descriptors and boiling points of 520 aliphatic alcohols,ethers,aldehydes,ketones,acids,and esters were obtained separately. The QSPRs between these descriptors and boiling points were developed for 520 aliphatic oxygen-containing organic compounds by best subsets regression method. For the training set,the correlation coefficient R2 is 0. 9946 and the standard deviation GO is 6. 70 K. For the test set,R2 is 0. 9857 and s is 6. 10 K. The average relative error is 1. 19%. According to the regression equation,the influences of the number of effective carbon of alkyl,the role of functional groups and their interaction on the boiling point were analyzed. These results showed a good correlation between the boiling points of organic compounds and these descriptors derived from PEI for aliphatic alcohols,ethers,aldehydes,ketones,acids,and esters.

  9. Effect of chlorination on the development of marine biofilms dominated by diatoms

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Jagadeesan, V.

    , and Thalassionema did not increase in density after chlorine treatment. It was also demonstrated that diatoms can colonize, grow and photosynthesize on chlorine-treated surfaces. Under pulse chlorination (treatment every 6 h), irrespective of chlorine concentration...

  10. Chlorination of organophosphorus pesticides in natural waters.

    Science.gov (United States)

    Acero, Juan L; Benítez, F Javier; Real, Francisco J; González, Manuel

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 degrees C and pH 7 were determined to be 110.9, 0.004 and 191.6 M(-1) s(-1) for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L(-1) was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  11. Effects of ozone and chlorine disinfection on VBNC Helicobacter pylori by molecular techniques and FESEM images.

    Science.gov (United States)

    Orta de Velásquez, María Teresa; Yáñez Noguez, Isaura; Casasola Rodríguez, Beatriz; Román Román, Priscila Ivette

    2017-03-01

    Helicobacter pylori is a pathogen bacteria associated with chronic gastritis, peptic ulceration, and gastric carcinoma. H. pylori has a spiral morphology, which under certain conditions of stress becomes a coccoid form. This type of morphology has been linked to a viable but non-culturable (VBNC) state, which is thought to allow its persistence in the environment. Membrane damage in VBNC H. pylori in water as a mechanism for inactivation using ozone (O3) and chlorine disinfection has not been reported in the literature. In this paper, disinfection assays with ozone and chlorine were conducted to evaluate their effects on VBNC H. pylori cells. The use of fluorescent dyes such as propidium monoazide (PMA) coupled with quantitative real-time polymerase chain reactions produced results necessary to assess the viability of the microorganism and demonstrate the effect of each disinfectant on the bacterial count. Applying ozone showed a 5-log bacterial reduction using a disinfectant concentration and exposure time (CT) of 4 mg min/L. Chlorine disinfection for the same 5-log reduction required a higher CT value. Field emission scanning electron microscope images of ozone-treated VBNC H. pylori also showed severe cell damage. The use of PMA revealed that chlorine produced physical damage in the membrane in addition to the known inhibiting effect on cell enzymatic processes. These findings are important for the detection and control of VBNC H. pylori cells in drinking water systems.

  12. The ability of single-chain surfactants to emulsify an aqueous-based liquid crystal oscillates with odd-even parity of alkyl-chain length.

    Science.gov (United States)

    Varghese, Nisha; Shetye, Gauri S; Yang, Sijie; Wilkens, Stephan; Smith, Robert P; Luk, Yan-Yeung

    2013-12-15

    The physical properties of many organic molecules often oscillate when the number of carbons in their aliphatic chains changes from odd to even. This odd-even effect for single-chain surfactants in solution is rarely observed. Here, we report the ability of single-chain surfactants to emulsify a class of non-amphiphilic organic salts, disodium cromoglycate (5'DSCG) oscillates as a function of the odd or even number of the aliphatic carbons. This system provides a water-in-oil-in-water emulsion, in which aqueous droplets of 5'DSCG in liquid crystal phases are coated with single-chain surfactants in a bulk carrying aqueous solution. For both surfactants of [Formula: see text] and CH3(CH2)nCOO(-)Na(+), the ability to emulsify 5'DSCG molecules in water is stronger for surfactants with an odd number of sp(3)-hybridized carbon atoms in the aliphatic chains than those with an even number. This observed odd-even effect is consistent with the notion that conventional micelles possess a core of randomly arranged surfactant hydrocarbon tails. However, this water-in-oil-in-water resembles a vesicle system in which the surfactants assemble in a highly ordered structure that separates two aqueous systems. These new self-assembled phases have potential application in the formulation and design of new organic soft materials.

  13. CZE study on adsorption processes of aliphatic and aromatic amines on PMMA chip.

    Science.gov (United States)

    Masár, Marián; Kruk, Pavol; Luc, Milan; Bodor, Róbert; Danč, Ladislav; Troška, Peter

    2013-02-01

    Adsorption processes on a PMMA chip linked with CZE separations of a group of 13 aliphatic and aromatic mono- and di-amines were studied. Due to the lack of chromophores within aliphatic amines, contact conductivity detection implemented directly onto the chip was used for monitoring of cationic CZE separations. To prevent an adsorption of studied amines to the chip channels, the surface of PMMA chip was modified by dynamic coating. Different surface modifiers, such as aliphatic oligoamines (diethylenetriamine and triethylenetetramine), were added to the BGE solutions filling the chip channels. The effect of various concentrations of surface modifiers on peak profiles and separation parameters of amines was monitored. Of these, mainly, aliphatic di-amines and aromatic mono-amines adversely affected the CZE resolution of a whole group of analytes by their strong adsorption to the chip channels. A propionate BGE with pH 3.2 containing 100 μM triethylenetetramine and 25 mM 18-crown-6-ether was found suitable for CZE resolution of 12 from a total of 13 amines studied. Simple dynamic modification of the surface of PMMA chip enabled fast (analysis time lasted 9 min), sensitive (sub-μM LODs reached) and reproducible (1-3% RSD of the peak areas) CZE analysis of the aliphatic and aromatic amines.

  14. The effects of low level chlorination and chlorine dioxide on biofouling control in a once-through service water system

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, W.E. Jr. [Alabama Power Co./GSC No. 8, Birmingham, AL (United States); Laylor, M.M. [Univ. of Alabama, Birmingham, AL (United States)

    1995-06-01

    Continuous chlorination has been successfully used for the control of Corbicula at a nuclear power plant located on the Chattahoochee River in southeastern Alabama, since 1986. The purpose of this study was to investigate further minimization of chlorine usage and determine if chlorine dioxide is a feasible alternative. Four continuous biocide treatments were evaluated for macro and microfouling control effectiveness, operational feasibility, and environmental acceptability. One semi-continuous chlorination treatment was also evaluated for macrofouling control effectiveness. Higher treatment residuals were possible with chlorine dioxide than with chlorination due to the river discharge limitations. At the levels tested, continuous chlorine dioxide was significantly more effective in providing both macro and microfouling control. Semi-continuous chlorination was just as effective as continuous chlorination for controlling macrofouling. The Corbicula treatment programs that were tested should all provide sufficient control for zebra mussels. Chlorine dioxide was not as cost effective as chlorination for providing macrofouling control. The semi-continuous treatment save 50% on chemical usage and will allow for the simultaneous treatment of two service water systems. Chlorite levels produced during the chlorine dioxide treatments were found to be environmentally acceptable. Levels of trihalomethanes in the chlorinated service water were less than the maximum levels allowed in drinking water.

  15. Microbiological aspects of the removal of chlorinated hydrocarbons from air

    NARCIS (Netherlands)

    Dolfing, Jan; Wijngaard, Arjan J. van den; Janssen, Dick B.

    1993-01-01

    Chlorinated hydrocarbons are widely used synthetic chemicals that are frequently present in industrial emissions. Bacterial degradation has been demonstrated for several components of this class of compounds. Structural features that affect the degradability include the number of chlorine atoms and

  16. Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Olsen, Jørn; Villeneuve, Sara;

    2013-01-01

    To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).......To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF)....

  17. Identification of intermediates leading to chloroform and C-4 diacids in the chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Erkelens, Corrie; Galan, L.

    1985-01-01

    The chlorination of terrestrial humic acid was studied at pH 7. 2 with varying chlorine to carbon ratios. The principal products are chloroform, di- and trichloroacetic acid, and chlorinated C-4 diacids. At a high chlorine dose many new chlorination products were detected, among them chlorinated aro

  18. In vitro mutagenicity and genotoxicity study of a number of short-chain chlorinated hydrocarbons using the micronucleus test and the alkaline single cell gel electrophoresis technique (Comet assay) in human lymphocytes: a structure-activity relationship (QSAR) analysis of the genotoxic and cytotoxic potential.

    Science.gov (United States)

    Tafazoli, M; Baeten, A; Geerlings, P; Kirsch-Volders, M

    1998-03-01

    Using the micronucleus (MN) test and the alkaline single cell gel electrophoresis (Comet) assay, potential mutagenicity (MN formation), genotoxicity (DNA breakage capacity) and cytotoxicity (cell proliferation reduction) of five chlorinated hydrocarbons (carbon tetrachloride, hexachloroethane, 1,2-dichloroethane, 1-chlorohexane and 2,3-dichlorobutane) have been evaluated in isolated human lymphocytes. With the MN test a low but statistically significant mutagenic activity was detected for all tested substances (except 2,3-dichlorobutane) with one out of the two donors and in the presence or absence of an exogenous metabolic activation system (S9 mix). However, at the concentration ranges tested none of the positive compounds induced a clear dose-dependent mutagenic effect. The Comet assay detected a strong DNA damaging effect for 1-chlorohexane, 2,3-dichlorobutane and 1,2-dichloroethane, but not for carbon tetrachloride and hexachloroethane. The influence of metabolism on the genotoxic activity of the chemicals was more clear in the Comet assay than in the MN test. The experimental genotoxicity and cytotoxicity data obtained in this study, together with data on five more related chemicals previously investigated, and their physico-chemical descriptors or electronic parameters have been used for QSAR analysis. The QSAR analysis high-lighted that the toxicity of the tested compounds was influenced by different parameters, like lipophilicity (logP), electron donor ability (charge) and longest carbon-chlorine (LBC-Cl) bond length. In addition, steric parameters, like molar refractivity (MR) and LBC-Cl, and electronic parameters, like ELUMO (energy of the lowest unoccupied molecular orbital, indicating electrophilicity), were predominant factors discriminating genotoxins from non-genotoxins in the presence but not in the absence of S9 mix. Although a limited number of compounds have been examined and cytotoxicity and genotoxicity were identified in two different

  19. Diurnal variation of stratospheric chlorine monoxide - A critical test of chlorine chemistry in the ozone layer

    Science.gov (United States)

    Solomon, P. M.; De Zafra, R.; Parrish, A.; Barrett, J. W.

    1984-01-01

    Ground-based observations of a mm-wave spectral line at 278 GHz have yielded stratospheric chlorine monoxide column density diurnal variation records which indicate that the mixing ratio and column density of this compound above 30 km are about 20 percent lower than model predictions based on 2.1 parts/billion of total stratospheric chlorine. The observed day-to-night variation is, however, in good agreement with recent model predictions, both confirming the existence of a nighttime reservoir for chlorine and verifying the predicted general rate of its storage and retrieval.

  20. Chlorine: Undergraduate Research on an Element of Controversy

    Science.gov (United States)

    Chang, Hasok

    2009-04-01

    If chemical elements were people, chlorine would be a celebrity. Although intrinsically no more or less important than any other element, chlorine has had a knack of making headlines. The genre of "object biography" has been quite successful in popular science recently. We took this opportunity to write a "biographical" study of chlorine. Chlorine's wide range of interesting controversies is well suited for attracting and maintaining the enthusiasm of the diverse range of students we teach in our department.

  1. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

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

    Science.gov (United States)

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

    2014-09-07

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

  3. On the inclusion of alkanes into the monolayer of aliphatic alcohols at the water/alkane vapor interface: a quantum chemical approach.

    Science.gov (United States)

    Vysotsky, Yuri B; Fomina, Elena S; Belyaeva, Elena A; Fainerman, Valentin B; Vollhardt, Dieter

    2013-02-14

    In the framework of the quantum chemical semiempirical PM3 method thermodynamic and structural parameters of the formation and clusterization of aliphatic alcohols C(n)H(2n+1)OH (n(OH) = 8-16) at 298 K at the water/alkane vapor C(n)H(2n+2), (n(CH(3)) = 6-16) interface were calculated. The dependencies of enthalpy, entropy and Gibbs' energy of clusterization per one monomer molecule of 2D films on the alkyl chain length of corresponding alcohols and alkanes, the molar fraction of alkanes in the monolayers and the immersion degree of alcohol molecules into the water phase were shown to be linear or stepwise. The threshold of spontaneous clusterization of aliphatic alcohols at the water/alkane vapor interface was 10-11 carbon atoms at 298 K which is in line with experimental data at the air/water interface. It is shown that the presence of alkane vapor does not influence the process of alcohol monolayer formation. The structure of these monolayers is analogous to those obtained at the air/water interface in agreement with experimental data. The inclusion of alkane molecules into the amphiphilic monolayer at the water/alkane vapor interface is possible for amphiphiles with the spontaneous clusterization threshold at the air/water interface (n(s)(0)) of at least 16 methylene units in the alkyl chain, and it does not depend on the molar fraction of alkanes in the corresponding monolayer. The inclusion of alkanes from the vapor phase into the amphiphilic monolayer also requires that the difference between the alkyl chain lengths of alcohols and alkanes is not larger than n(s)(0) - 15 and n(s)(0) - 14 for the 2D film 1 and 2D film 2, respectively.

  4. Evaluation of the Most Current and Effective Methods in the Analysis of Chlorinated Dioxins in Ground Beef

    Directory of Open Access Journals (Sweden)

    Ebere C. Anyanwu

    2003-01-01

    Full Text Available Chlorinated dioxins are the group of environmental pollutants consisting of 210 chlorinated dibenzo-p-dioxins and dibenzofurans. They are highly toxic and persistent. They are lipophilic and can easily biomagnify in the food chain, hence posing a serious threat to human health. The daily consumption of low-level contaminated food, mainly of animal origin, leads to the accumulation of dioxins in the human body. The exposures of the general human population to dioxins and the specific issues of a risk assessment of dioxin pose serious concerns in public environmental and nutritional health. This paper reviews the analysis of chlorinated dioxins in ground beef. The sources of contamination of chlorinated dioxins in ground beef are first reviewed to form a basis for a clear understanding of the health implications of chlorinated dioxins in the human food chain and why it is necessary to monitor the level of dioxins in animal food products, especially ground beef. The methods of collection, sampling, and processing of ground beef, and the methods of sample clean up prior to the analysis, are reviewed. Emphasis is laid on the new techniques that are available and that might be effective in the analysis of chlorinated dioxins in ground beef. Among these new methods and techniques are: the synergistic combination of ELISA/GC/MS, direct sample introduction to /GC/MS-MS, automated clean-up method, and the supercritical fluid extraction methods. The possible treatments of results from each method and technique are discussed and their respective efficiencies are compared. Finally, quality control and quality assurance parameters are evaluated for levels of accuracy, reproducibility, and precision.

  5. ORGANIC CHEMISTRY. Catalytic asymmetric hydroamination of unactivated internal olefins to aliphatic amines.

    Science.gov (United States)

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

    2015-07-01

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

  6. Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution.

    Science.gov (United States)

    Liu, Chao; Wang, Xiaoqing; Li, Zhaodong; Cui, Lei; Li, Chaozhong

    2015-08-12

    We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH3CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation.

  7. Chlorination of nickel ore by gaseous chlorine in the presence of active additives

    Directory of Open Access Journals (Sweden)

    Ilić Ilija B.

    2003-01-01

    Full Text Available Paper presents a thermodynamic analysis of chemical reactions occurring during chlorination with and without additives for both nickel oxides and nickel ferrites, which are component parts of nickel ore. The experimental research investigated the influence of temperature in the range from 600 up to 1000 °C and time (up to 3 h on the chlorination degree of nickel ores with and without additives. It was found that the introduction of additives such as C, S, BaS and NaCl intensified the chlorination of nickel ore. The results can be applied and may help determine the optimal conditions for the chlorination of low-grade ferrous nickel ores.

  8. Click synthesis of neutral, cationic, and zwitterionic poly(propargyl glycolide)-co-poly(ɛ-caprolactone)-based aliphatic polyesters as antifouling biomaterials.

    Science.gov (United States)

    Tu, Qin; Wang, Jian-Chun; Liu, Rui; Chen, Yun; Zhang, Yanrong; Wang, Dong-En; Yuan, Mao-Sen; Xu, Juan; Wang, Jinyi

    2013-08-01

    With the development of polymer-based biomaterials, aliphatic polyesters have attracted considerable interest because of their non-toxicity, non-allergenic property, and good biocompatibility. However, the hydrophobic nature and the lack of side chain functionalities of aliphatic polyesters limit their biomedical applications. In this study, we prepared four new polyesters: poly(sulfobetaine methacrylate)-, poly(2-methacryloyloxyethyl phosphotidylcholine)-, poly(ethylene glycol)-, and quaternized poly[(2-dimethylamino)ethyl methacrylate]-grafted poly(propargyl glycolide)-co-poly(ɛ-caprolactone). Their synthesis was conducted through ring-opening polymerization of acetylene-functionalized lactones and subsequent graft of bioactive units using click chemistry. The chemical structures of the polyesters were characterized through nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. For studies on their hydrophilicity, stability, and anti-bioadhesive property, a series of polymeric surfaces of these polyesters was prepared by coating them onto glass substrates. The hydrophilicity and stability of these polyester surfaces were examined by contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy. Their anti-bioadhesive property was investigated through protein adsorption, as well as cellular and bacterial adhesion assays. The prepared polyesters showed good hydrophilicity and long-lasting stability, as well as significant anti-fouling property. The newly prepared polyesters could be developed as promising anti-fouling materials with extensive biomedical applications.

  9. Effect of Hydroxyapatite Nanoparticles on the Degradability of Random Poly(butylene terephthalate-co-aliphatic dicarboxylates Having a High Content of Terephthalic Units

    Directory of Open Access Journals (Sweden)

    Nina Heidarzadeh

    2016-07-01

    Full Text Available Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The second synthesis step was a thermal transesterification between the corresponding homopolymers, always attaining a random distribution as verified by NMR spectroscopy. Hybrid polymer composites containing 2.5 wt % of hydroxyapatite (HAp were also prepared by in situ polymerization. Hydroxyl groups on the nanoparticle surface allowed the grafting of polymer chains in such a way that composites were mostly insoluble in the typical solvents of the parent copolyesters. HAp had some influence on crystallization from the melt, thermal stability, and mechanical properties. HAp also improved the biocompatibility of samples due to the presence of Ca2+ cations and the damping effect of phosphate groups. Interestingly, HAp resulted in a significant increase in the hydrophilicity of samples, which considerably affected both enzymatic and hydrolytic degradability. Slight differences were also found in the function of the dicarboxylic component, as the lowest degradation rates was found for the sample constituted of the most hydrophobic sebacic acid units.

  10. UV/chlorine as an advanced oxidation process for the degradation of benzalkonium chloride: Synergistic effect, transformation products and toxicity evaluation.

    Science.gov (United States)

    Huang, Nan; Wang, Ting; Wang, Wen-Long; Wu, Qian-Yuan; Li, Ang; Hu, Hong-Ying

    2017-05-01

    Benzalkonium chlorides (BACs), as typical cationic surfactants and biocides widely applied in household and industrial products, have been frequently detected as micropollutants in many aquatic environments. In this study, the combination of UV irradiation and chlorine (UV/chlorine), a newly interested advanced oxidation process, was used to degrade dodecylbenzyldimethylammonium chloride (DDBAC). UV/chlorine showed synergistic effects on DDBAC degradation comparing to UV irradiation or chlorination alone. Radical quenching experiments indicated that degradation of DDBAC by UV/chlorine involved both UV photolysis and radical species oxidation, which accounted for 48.4% and 51.6%, respectively. Chlorine dosage and pH are essential parameters affecting the treatment efficiency of UV/chlorine. The pseudo first order rate constant (kobs, DDBAC) increased from 0.046 min(-1) to 0.123 min(-1) in response to chlorine dosage at 0-150 mg/L, and the degradation percentage of DDBAC within 12 min decreased from 81.4% to 56.6% at pH 3.6-9.5. Five main intermediates were identified and semi-quantified using HPLC-MS/MS and a possible degradation pathway was proposed. The degradation mechanisms of DDBAC by UV/chlorine included cleavage of the benzyl-nitrogen bond and hydrogen abstraction of the alkyl chain. Trichloromethane (TCM), chloral hydrate (CH), trichloropropanone (TCP), dichloropropanone (DCP) and dichloroacetonitrile (DCAN) were detected using GC-ECD. The formation of chlorinated products increased rapidly initially, then decreased (TCM, TCP, DCP and DCAN) or remained stable (CH) with extended treatment. The actual formation of TCM peaked at 30 min (50.3 μg/L), while other chlorinated products did not exceed 10 μg/L throughout the process. Based on the luminescent bacterial assay, DDBAC solution underwent almost complete detoxification subjected to UV/chlorine treatment for 120 min, which is more effective than UV irradiation or chlorination alone.

  11. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    OpenAIRE

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested o...

  12. Chlorinated organic compounds in urban river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Soma, Y.; Shiraishi, H.; Inaba, K. [National Inst. of Environmental Studies, Tsukuba, Ibaraki (Japan)

    1995-12-31

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

  13. Method and apparatus for producing chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Santillie, P.W.; Ramras, D.M.

    1984-05-29

    A continuous method and apparatus are described for the efficient production of gaseous chlorine dioxide by the reaction between gaseous sulfur dioxide and an aqueous solution of a metallic chlorate. The chlorate solution and a highly concentrated sulfur dioxide gas are introduced into a packed columnar chamber at closely adjacent locations at the bottom of the chamber so as to flood the chamber and maximize both the contact area and contact time of the two reactants. Throughout the reaction the chamber is subjected to high vacuum imposed by an eductor which exhausts the chlorine dioxide gas and spent reactants. For use of the chlorine dioxide to produce potable water or treat foodstuffs, the chlorine dioxide and spent reactants are exhausted from the chamber separately by respective eductors substantially balanced with respect to each other to impose comparable vacuums upon the chamber. Because of the high efficency of the reaction, substantial heat is generated therefrom which is absorbed by a coolant flowing through a jacket surrounding the chamber. The flow rate of the coolant and flow rate of the reactants into the chamber are porportional due to the dependency of the reactant flow rate on the coolant flow rate.

  14. Photoabsorption and photoionization of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Flesch, R.; Ruehl, E.; Hottmann, K.; Baumgaertel, H. (Freie Universitaet Berlin (Germany))

    1993-01-28

    Photoprocesses of chlorine dioxide in the near-UV have become highly important for stratospheric photoprocesses at high latitudes, especially in Antarctica. Chlorine dioxide has been identified among other absorbers because of its specific absorption cross section in the near-UV. Possible contributions of chlorine dioxide photochemistry to polar ozone depletion have been discussed recently. The high-resolution He I photoelectron spectrum and the absolute (vacuum-UV) absorption cross section (6-25 eV) as well as the ionic fragmentation of chlorine dioxide (OCIO) are reported. The photoelectron spectrum is interpreted in terms of exchange splitting effects of the various singlet and triplet cation states as well as by comparison to chemically related molecules. The vacuum-UV absorption spectrum shows different Rydberg series converging to the cation states. These Rydberg series and their vibrational progressions are assigned by term value arguments, dipole selection rules, and comparison with the photoelectron spectrum. Photoionization mass spectrometry is used for measurements of the ionization and fragmentation threshold of OCIO. The major fragment is ClO[sup +] which occurs above 13.4 eV. Thermomechanical data such as heats of formation and bond dissociation energies are derived. No evidence for isomerization of OClO[sup +] is found, as observed for the electronically excited neutral molecule. 54 refs., 6 figs., 7 tabs.

  15. Inhibitor treatment program for chlorine dioxide corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Edmondson, J.G.; Holder, E.P.

    1991-11-12

    This patent describes a method of inhibiting corrosion by chlorine dioxide in oil field waterflood systems by adding a sufficient amount of a corrosion inhibiting composition. It comprises a phosphonate, a copolymer consisting of repeating units of acrylic acid/allyl hydroxy propyl sulfonate ether, and a permangante.

  16. Lipase-catalyzed synthesis of aliphatic polyesters via copolymerization of lactone, dialkyl diester, and diol.

    Science.gov (United States)

    Jiang, Zhaozhong

    2008-11-01

    Candida antarctica lipase (CALB) has been successfully used as catalyst for copolymerization of dialkyl diester with diol and lactone to form aliphatic polyesters. The polymerization reactions were performed using a two stage process: first stage oligomerization under low vacuum followed by second stage polymerization under high vacuum. Use of the two-stage process is required to obtain products with high molecular weights at high yields for the following reasons: (i) the first stage reaction ensures that the monomer loss via evaporation is minimized to maintain 1:1 diester to diol stoichiometric ratio, and the monomers are converted to nonvolatile oligomers; (ii) use of high vacuum during the second stage accelerates equilibrium transesterification reactions to transform the oligomers to high molecular weight polymers. Thus, terpolymers of omega-pentadecalactone (PDL), diethyl succinate (DES), and 1,4-butanediol (BD) with a M w of whole product (nonfractionated) up to 77000 and M w/ M n between 1.7 and 4.0 were synthesized in high yields (e.g., 95% isolated yield). A desirable reaction temperature for the copolymerizations was found to be around 95 degrees C. At 1:1:1 PDL/DES/BD monomer molar ratio, the resultant terpolymers contained equal moles of PDL, succinate, and butylene repeat units in the polymer chains. (1)H and (13)C NMR analyses were used to determine the polyester microstructures. The synthesized PDL-DES-BD terpolymers possessed near random structures with all possible combinations of PDL, succinate, and butylene units via ester linkages in the polymer backbone. Furthermore, thermal stability and crystallinity of a pure PDL-DES-BD terpolymer with 1:1:1 PDL to succinate to butylene unit ratio and M w of 85400 were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The copolyester was found to be a semicrystalline material with a T g of -34 degrees C and a T m of 64 degrees C, which degrades in a single weight loss

  17. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  18. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Science.gov (United States)

    2010-07-01

    ... diamine and phenol, reaction products with 4-methyl-2-pentanone (generic). 721.10190 Section 721.10190... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  19. Environmentally benign synthesis of saturated and unsaturated aliphatic polyesters via enzymatic polymerization of biobased monomers derived from renewable resources

    NARCIS (Netherlands)

    Jiang, Yi; Woortman, Albert J. J.; van Ekenstein, Gert O. R. Alberda; Loos, Katja

    2015-01-01

    Aliphatic polyesters are of great interest due to their broad potential applications and sustainability. Itaconate-based aliphatic polyesters are even more appealing in biomedical and pharmaceutical fields, as they are renewable functional polymers that can be biodegradable, biocompatible, and photo

  20. Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis.

    Science.gov (United States)

    Hering, Thea; Mühldorf, Bernd; Wolf, Robert; König, Burkhard

    2016-04-18

    Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal-catalyzed cross-couplings. Nature chlorinates with chloride anions, FAD-dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket.

  1. Kinetic models and pathways of ronidazole degradation by chlorination, UV irradiation and UV/chlorine processes.

    Science.gov (United States)

    Qin, Lang; Lin, Yi-Li; Xu, Bin; Hu, Chen-Yan; Tian, Fu-Xiang; Zhang, Tian-Yang; Zhu, Wen-Qian; Huang, He; Gao, Nai-Yun

    2014-11-15

    Degradation kinetics and pathways of ronidazole (RNZ) by chlorination (Cl2), UV irradiation and combined UV/chlorine processes were investigated in this paper. The degradation kinetics of RNZ chlorination followed a second-order behavior with the rate constants calculated as (2.13 ± 0.15) × 10(2) M(-2) s(-1), (0.82 ± 0.52) × 10(-2) M(-1) s(-1) and (2.06 ± 0.09) × 10(-1) M(-1) s(-1) for the acid-catalyzed reaction, as well as the reactions of RNZ with HOCl and OCl(-), respectively. Although UV irradiation degraded RNZ more effectively than chlorination did, very low quantum yield of RNZ at 254 nm was obtained as 1.02 × 10(-3) mol E(-1). RNZ could be efficiently degraded and mineralized in the UV/chlorine process due to the generation of hydroxyl radicals. The second-order rate constant between RNZ and hydroxyl radical was determined as (2.92 ± 0.05) × 10(9) M(-1) s(-1). The degradation intermediates of RNZ during the three processes were identified with Ultra Performance Liquid Chromatography - Electrospray Ionization - mass spectrometry and the degradation pathways were then proposed. Moreover, the variation of chloropicrin (TCNM) and chloroform (CF) formation after the three processes were further evaluated. Enhanced formation of CF and TCNM precursors during UV/chlorine process deserves extensive attention in drinking water treatment.

  2. Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries.

    Science.gov (United States)

    Preston, Kelsey; Lantagne, Daniele; Kotlarz, Nadine; Jellison, Kristen

    2010-03-01

    Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.

  3. Aliphatic carboxylic acids as new modifiers for separation of 2,4-dinitrophenyl amino acids by micellar liquid chromatography.

    Science.gov (United States)

    Boichenko, Alexander P; Kulikov, Artem U; Loginova, Lidia P; Iwashchenko, Anna L

    2007-07-20

    The possibilities of isocratic separation of 2,4-dinitrophenyl derivatives of 12 amino acids that considerably differ in hydrophobicity by micellar mobile phases with different organic modifiers have been discussed. For the first time aliphatic carboxylic acids have been used as modifiers of micellar eluent in micellar liquid chromatography with C18 columns. Elution strength of hybrid micellar phases on the basis of sodium dodecylsulfate and aliphatic carboxylic acids increases in sequence: aceticacid. The effect of sodium dodecylsulfate micelles on aliphatic carboxylic acids has been characterized by their micellar-induced shifts of ionization constants. The use of aliphatic carboxylic acids as modifiers of SDS micellar eluents provides better overall resolution of 2,4-dinitrophenyl-amino acids in comparison with aliphatic alcohols.

  4. Controlled oxidation of aliphatic CH bonds in metallo-monooxygenases: mechanistic insights derived from studies on deuterated and fluorinated hydrocarbons.

    Science.gov (United States)

    Chen, Yao-Sheng; Luo, Wen-I; Yang, Chung-Ling; Tu, Yi-Jung; Chang, Chun-Wei; Chiang, Chih-Hsiang; Chang, Chi-Yao; Chan, Sunney I; Yu, Steve S-F

    2014-05-01

    The control over the regio- and/or stereo-selective aliphatic CH oxidation by metalloenzymes is of great interest to scientists. Typically, these enzymes invoke host-guest chemistry to sequester the substrates within the protein pockets, exploiting sizes, shapes and specific interactions such as hydrogen-bonding, electrostatic forces and/or van der Waals interactions to control the substrate specificity, regio-specificity and stereo-selectivity. Over the years, we have developed a series of deuterated and fluorinated variants of these hydrocarbon substrates as probes to gain insights into the controlled CH oxidations of hydrocarbons facilitated by these enzymes. In this review, we illustrate the application of these designed probes in the study of three monooxygenases: (i) the particulate methane monooxygenase (pMMO) from Methylococcus capsulatus (Bath), which oxidizes straight-chain C1-C5 alkanes and alkenes to form their corresponding 2-alcohols and epoxides, respectively; (ii) the recombinant alkane hydroxylase (AlkB) from Pseudomonas putida GPo1, which oxidizes the primary CH bonds of C5-C12 linear alkanes; and (iii) the recombinant cytochrome P450 from Bacillus megaterium, which oxidizes C12-C20 fatty acids at the ω-1, ω-2 or ω-3 CH positions.

  5. Enteric polymer based on pH-responsive aliphatic polycarbonate functionalized with vitamin E to facilitate oral delivery of tacrolimus.

    Science.gov (United States)

    Wang, Menglin; Sun, Jin; Zhai, Yinglei; Lian, He; Luo, Cong; Li, Lin; Du, Yuqian; Zhang, Dong; Ding, Wenya; Qiu, Shuhong; Liu, Yuhai; Kou, Longfa; Han, Xiangfei; Xiang, Rongwu; Wang, Yongjun; He, Zhonggui

    2015-04-13

    To improve the bioavailability of orally administered drugs, we synthesized a pH-sensitive polymer (poly(ethylene glycol)-poly(2-methyl-2-carboxyl-propylene carbonate)-vitamin E, mPEG-PCC-VE) attempting to integrate the advantages of enteric coating and P-glycoprotein (P-gp) inhibition. The aliphatic polycarbonate chain was functionalized with carboxyl groups and vitamin E via postpolymerization modification. Optimized by comparison and central composite design, mPEG113-PCC32-VE4 exhibited low critical micelle concentration of 1.7 × 10(-6) mg/mL and high drug loading ability for tacrolimus (21.2% ± 2.7%, w/w). The pH-responsive profile was demonstrated by pH-dependent swelling and in vitro drug release. Less than 4.0% tacrolimus was released under simulated gastric fluid after 2.5 h, whereas an immediate release was observed under simulated intestinal fluid. The mPEG113-PCC32-VE4 micelles significantly increased the absorption of P-gp substrate tacrolimus in the whole intestine. The oral bioavailability of tacrolimus micelles was 6-fold higher than that of tacrolimus solution in rats. This enteric polymer therefore has the potential to become a useful nanoscale carrier for oral delivery of drugs.

  6. Chain Gang

    Science.gov (United States)

    2006-01-01

    6 August 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a chain of clustered and battered craters. These were formed by secondary impact. That is, somewhere to the south (beyond the bottom of this image), a large impact crater formed. When this occurred, material ejected from the crater was thrown tens to hundreds of kilometers away. This material then impacted the martian surface, forming clusters and chains of smaller craters. Location near: 15.8oN, 35.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Northern Spring

  7. Swift heavy ion induced modification of aliphatic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Umme Habiba

    2015-01-15

    In this thesis, the high energy heavy ion induced modification of aliphatic polymers is studied. Two polymer groups, namely polyvinyl polymers (PVF, PVAc, PVA and PMMA) and fluoropolymers (PVDF, ETFE, PFA and FEP) were used in this work. Polyvinyl polymers were investigated since they will be used as insulating materials in the superconducting magnets of the new ion accelerators of the planned International Facility for Antiproton and Ion Research (FAIR) at the GSI Helmholtz-Centre of Heavy Ion Research (GSI) in Darmstadt. In order to study ion-beam induced degradation, all polymer foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (U, Au, Sm, Xe) and experimentation sites (beam lines X0 and M3) over a large fluence regime (1 x 10{sup 10} - 5 x 10{sup 12} ions/cm{sup 2}). Five independent techniques, namely infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy, residual gas analysis (RGA), thermal gravimetric analysis (TGA), and mass loss analysis (ML), were used to analyze the irradiated samples. FT-IR spectroscopy revealed that ion irradiation led to the decrease of characteristic band intensities showing the general degradation of the polymers, with scission of side groups and the main backbone. As a consequence of the structural modification, new bands appeared. UV-Vis transmission analysis showed an absorption edge shift from the ultraviolet region towards the visible region indicating double bond and conjugated double bond formation. On-line massspectrometric residual gas analysis showed the release of small gaseous fragment molecules. TGA analysis gave evidence of a changed thermal stability. With ML analysis, the considerable mass loss was quantified. The results of the five complementary analytical methods show how heavy ion irradiation changes the molecular structure of the polymers. Molecular degradation mechanisms are postulated. The amount of radiation damage is found to be sensitive to the used type of ionic

  8. Selection of ionic liquids for the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures

    NARCIS (Netherlands)

    Meindersma, G. Wytze; Podt, Anita (J.G.); Haan, de André B.

    2005-01-01

    The separation of aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) from C4 to C10 aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. In this work, we investigated the separation of t

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

    NARCIS (Netherlands)

    Beekwilder, J.; van Leeuwen, W.; Van Dam, N.M.; Bertossi, M.; Grandi, V.; Mizzi, L.; Soloviev, M.; Szabados, L.; Molthoff, J.W.; Schipper, B.; Verbocht, H.; de Vos, R.C.H.; Morandini, P.; Aarts, M.G.M.; Bovy, A.

    2008-01-01

    Aliphatic glucosinolates are compounds which occur in high concentrations in Arabidopsis thaliana and other Brassicaceae species. They are important for the resistance of the plant to pest insects. Previously, the biosynthesis of these compounds was shown to be regulated by transcription factors MYB

  10. Catalytic conversion of aliphatic alcohols on carbon nanomaterials: The roles of structure and surface functional groups

    Science.gov (United States)

    Tveritinova, E. A.; Zhitnev, Yu. N.; Chernyak, S. A.; Arkhipova, E. A.; Savilov, S. V.; Lunin, V. V.

    2017-03-01

    Carbon nanomaterials with the structure of graphene and different compositions of the surface groups are used as catalysts for the conversion of C2-C4 aliphatic alcohols. The conversions of ethanol, propanol- 1, propanol-2, butanol-1, butanol-2, and tert-butanol on carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are investigated. Oxidized and nonoxidized multiwalled carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are synthesized. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning and transmission electronic microscopies, Brunauer-Emmett-Teller method, derivatographic analyses, and the pulsed microcatalytic method are used to characterize comprehensively the prepared catalysts. It was established that all of the investigated carbon nanomaterials (with the exception of nondoped carbon nanoflakes) are bifunctional catalysts for the conversion of aliphatic alcohols, and promote dehydration reactions with the formation of olefins and dehydrogenation reactions with the formation of aldehydes or ketones. Nanoflakes doped with nitrogen are inert with respect to secondary alcohols and tert-butanol. The role of oxygen-containing and nitrogen-containing surface groups, and of the geometrical structure of the carbon matrix of graphene nanocarbon materials in the catalytic conversion of aliphatic alcohols, is revealed. Characteristics of the conversion of aliphatic alcohols that are associated with their structure are identified.

  11. Biological evaluation of porous aliphatic polyurethane/hydroxyapatite composite scaffolds for bone tissue engineering.

    NARCIS (Netherlands)

    Yang, W; Both, S.K.; Zuo, Y.; Birgani, Z.T.; Habibovic, P.; Li, Y.; Jansen, J.A.; Yang, F.

    2015-01-01

    Biomaterial scaffolds meant to function as supporting structures to osteogenic cells play a pivotal role in bone tissue engineering. Recently, we synthesized an aliphatic polyurethane (PU) scaffold via a foaming method using non-toxic components. Through this procedure a uniform interconnected porou

  12. Fingerprinting aliphatic hydrocarbon pollutants over agricultural lands surrounding Tehran oil refinery.

    Science.gov (United States)

    Bayat, Javad; Hashemi, Seyed Hossein; Khoshbakht, Korros; Deihimfard, Reza

    2016-11-01

    The analysis of aliphatic hydrocarbons, which are composed of n-alkanes as well as branched and cyclic alkanes, can be used to distinguish between the sources of hydrocarbon contamination. In this study, the concentration of aliphatic hydrocarbons, soil pH, and organic matter in agricultural soils located south of Tehran were monitored. Eighty-three soil samples were taken from two depth ranges of 0-30 and 30-60 cm. The results showed that aliphatic compounds ranged from 0.22-68.11 mg kg(-1) at the top to 0.33-53.18 mg kg(-1) at subsoil. The amount of hydrocarbons increases from the northern parts toward the south, and hydrocarbon pollutants originated from both petroleum and non-petroleum sources. Higher concentrations of aliphatic compounds in the southern parts indicated that, aside from the practice of irrigating with untreated wastewater, leakage from oil refinery storage tanks possibly contributed to soil pollution. The results also showed that several sources have polluted the agricultural soils. It is necessary to develop a new local pollution criterion as a diagnostic index that includes not only hydrocarbons but also other parameters such as heavy metal content in both soil and untreated wastewater, surface runoff, and other irrigation water resources to determine the exact origin of pollution.

  13. Palladium-catalyzed regioselective decarboxylative alkylation of arenes and heteroarenes with aliphatic carboxylic acids.

    Science.gov (United States)

    Premi, Chanchal; Dixit, Ankit; Jain, Nidhi

    2015-06-05

    An unprecedented Pd(OAc)2-catalyzed decarboxylative alkylation of unactivated arenes, with aliphatic carboxylic acids as inexpensive alkyl sources, is reported. The alkylation, controlled by the directing group, is regioselective, shows high functional group tolerance, and provides mild access to alkylated indolines, 2-phenylpyridines, and azobenzenes under solvent-free conditions in moderate to high yields.

  14. Mass spectral analysis of C3 and C4 aliphatic amino acid derivatives.

    Science.gov (United States)

    Lawless, J. G.; Chadha, M. S.

    1971-01-01

    Diagnostic criteria are obtained for the distinction of alpha, beta, gamma, and N-methyl isomers of the C3 and C4 aliphatic amino acids, using mass spectral analysis of the derivatives of these acids. The use of deuterium labeling has helped in the understanding of certain fragmentation pathways.

  15. PcMtr, an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum

    NARCIS (Netherlands)

    Trip, H; Evers, ME; Driessen, AJM

    2004-01-01

    The gene encoding an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum was cloned, functionally expressed and characterized in Saccharomyces cerevisiae M4276. The permease, designated PcMtr, is structurally and functionally homologous to Mtr of Neurospora crassa, and unre

  16. STUDY ON THE PHASE TRANSITION KINETICS OF THERMOTROPIC LIQUID CRYSTALLINE AROMATIC-ALIPHATIC COPOLYESTER

    Institute of Scientific and Technical Information of China (English)

    LI Minhui; WANG Xiaogong; LIU Deshan; ZHOU Qixiang

    1991-01-01

    The phase transition kinetics of thermotropic liquid crystalline aromatic-aliphatic regular copolyester:(X) were studied by DSC. By means of Kissinger's method the kinetic equation and parameters including activation energy, rate order and preexponential factor for phase transition from nematic to isotropic were obtained. The activation energy from crystal to nematic was also presented.

  17. A case study on the myth of emission from aliphatic amides

    Science.gov (United States)

    Singh, Avinash Kumar; Das, Sreyashi; Datta, Anindya

    2016-12-01

    For several decades, aliphatic amidic compounds have been believed to be emissive. We report that this contention is incorrect and that the anomalous emission from amides originates in fluorescent impurities generated during their synthesis. In order to make this point, we have synthesized fluorescent compounds and have compared the absorption spectra with excitation spectra.

  18. Recovery of Aliphatic Hydrocarbons from Oil Field Sludge using Bacillus sp

    Directory of Open Access Journals (Sweden)

    Rizwan Ahmed Bhutto

    2015-04-01

    Full Text Available Bioremediation of aliphatic HC (Hydrocarbons in the oily sludge of Kunnar oil and gas field, Pakistan was attempted by means of previously isolated and developed Bacillus sp. Both autoclaved and non-autoclaved sludge samples were analyzed for a reaction time of 30 days with pH 7 and temperature of 380C in 50 ml MSM growth media for the sludge concentration of 5, 10 and 50% with 2, 4 and 6ml of Bacillus sp. relatively, in air atmosphere. Stabilization of the samples by microbial activity resulted in the decrease in TPH (Total Petroleum Hydrocarbon concentration by 60, 69 and 87% in autoclaved samples in contrast to the decrease of 70, 84 and 94% observed in non-autoclaved samples, relatively. Hydrocarbon degradation in oily sludge was investigated via GC which transpired that 97 and 99% concentration of aliphatic hydrocarbons in autoclaved and non-autoclaved samples was removed at 5% of TPH concentration, relatively. However, with 10% TPH concentration aliphatic hydrocarbons reduction was 68% in autoclaved samples to that of 87% in non-autoclaved samples. Further increase in the hydrocarbons concentration by 50% yielded in the removal of aliphatic hydrocarbons by 65% in autoclaved samples as compared to 98% decrease in non-autoclaved samples.

  19. Aliphatic fatty acids and esters: inhibition of growth and exoenzyme production of Candida, and their cytotoxicity in vitro: anti-Candida effect and cytotoxicity of fatty acids and esters.

    Science.gov (United States)

    Souza, Juliana L S; da Silva, Adriana F; Carvalho, Pedro H A; Pacheco, Bruna S; Pereira, Cláudio M P; Lund, Rafael G

    2014-09-01

    The secretion of extracellular phospholipases and proteinases of Candida has been described as a relevant virulence factor in human infections. Aliphatic fatty acids have antimicrobial properties, but the mechanism by which they affect the virulence factors of microorganisms, such as Candida, is still unclear, and there are a few reports about their toxicity. The current study investigated the in vitro antifungal activity, exoenzyme production and cytotoxicity of some aliphatic fatty acids and their ester derivatives against the Candida species. The minimum inhibitory concentration and minimum fungicidal concentrations of aliphatic medium-chain fatty acids, methyl and ethyl esters were performed using the CLSI M27-A3 method and the cytotoxicity assay was performed according to ISO 10993-5. The influence of these compounds in the inhibition of the production of hydrolytic enzymes, phospholipases and proteinases by Candida was also investigated. Data analysis was performed using the one-way ANOVA method (p≤0.05). In relation to the MIC against Candida species, the fatty acid with the best result was Lauric acid, although its ester derivatives showed no activity. The inhibition of phospholipase production was more significant than the inhibition of proteinase production by Candida. Tested fatty acids revealed more than 80% cell viability in their MIC concentrations. Additionally, a cell viability of 100% was reported at concentrations of anti-enzymatic effect. Therefore, the potential use of these fatty acids could be the basis for more antimicrobial tests.

  20. Fate of PBDEs during food processing: Assessment of formation of mixed chlorinated/brominated diphenyl ethers and brominated dioxins/furans.

    Science.gov (United States)

    Roszko, Marek; Szymczyk, Krystyna; Jędrzejczak, Renata

    2015-01-01

    The aim of this study was to evaluate effects of food processing on PBDE levels, in particular influence of heat treatment on degradation of PBDEs, including possible formation of chlorinated diphenyl ethers or brominated dioxins/furans as degradation products. It was shown that PBDEs heated in the presence of chlorine (from either organic or inorganic sources) formed mixed chlorinated/brominated diphenyl ethers. However, no PCDEs were formed in the presence of lipids. Lipid medium increased stability of PBDEs exposed to UV irradiation. Profile of congeners formed in result of the debromination reaction was significantly different than profiles observed by some other authors in aliphatic organic solvents. Grilling processes increased concentrations (calculated on the fresh product basis) of the studied compounds by 4-8/22-34% for electric/coal grill, respectively. Depending on the congener and on the applied heat treatment, PBDE mass in pork meat after grilling dropped by 26-53%. No detectable quantities of either brominated dioxins or furans were formed during thermal processing of food containing typical levels of PBDEs.

  1. Coadsorption of low-molecular weight aromatic and aliphatic alcohols and acids with the cationic surfactant, CTAB, on silica surfaces.

    Science.gov (United States)

    Wangchareansak, Thipvaree; Keniry, Max A; Liu, Guangming; Craig, Vincent S J

    2014-06-17

    We have investigated the coadsorption of a range of small molecules with the cationic surfactant CTAB to silica surfaces over a range of concentrations and CTAB to solute ratios and compared the coadsorption with adsorption in the presence of the salicylate ion. We find that molecules with aromatic character and molecules with double bonds are most favorably adsorbed, and we attribute this to cation-π bonding between the surfactant headgroups and the π orbitals of the unsaturated bonds of the solute molecules. The adsorption is complex and depends on chemical interactions between the solute molecules and the surfactant, which are highly specific to the structure of the solute. To improve our understanding of the specifics of these interactions, we have performed one-dimensional rotating frame Overhauser spectroscopy (ROESY) nuclear magnetic resonance experiments. These experiments show the complexity of the intermolecular interactions and can be used to determine the position of the solute molecule with regard to the CTAB molecules in the adsorbed aggregates. The ROESY spectrum for the salicylate anion is distinct from those of the other solute molecules and suggests that the anions are dimerizing. Along with the cation-π bonding between the dimers, this provides a model for the strong influence that salicylate has on adsorption, micellar structure, and viscoelasticity. The ROESY data indicate that the catechol molecule interacts with all parts of the surfactant alkane chains such that they wrap around the molecule, but this has little effect on the interfacial curvature or aggregate shape. More intense isophthalic acid-CTAB intermolecular ROEs compared to those of other aromatic solutes are consistent with an interaction between isophthalic acid and the headgroups of two surfactant molecules that slows the intramicellar motion of isophthalic acid. Differences in interactions between solute molecules and the aliphatic surfactant chains do not result in changes

  2. Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Onstad, Gretchen D; Kull, Tomas P J; Metcalf, James S; Acero, Juan L; von Gunten, Urs

    2007-08-01

    As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.

  3. Chlorine hazard evaluation for the zinc-chlorine electric vehicle battery. Final technical report. [50 kWh

    Energy Technology Data Exchange (ETDEWEB)

    Zalosh, R. G.; Bajpai, S. N.; Short, T. P.; Tsui, R. K.

    1980-04-01

    Hazards associated with conceivable accidental chlorine releases from zinc-chlorine electric vehicle batteries are evaluated. Since commercial batteries are not yet available, this hazard assessment is based on both theoretical chlorine dispersion models and small-scale and large-scale spill tests with chlorine hydrate (which is the form of chlorine storage in the charged battery). Six spill tests involving the chlorine hydrate equivalent of a 50-kWh battery indicate that the danger zone in which chlorine vapor concentrations intermittently exceed 100 ppM extends at least 23 m directly downwind of a spill onto a warm (30 to 38/sup 0/C) road surface. Other accidental chlorine release scenarios may also cause some distress, but are not expected to produce the type of life-threatening chlorine exposures that can result from large hydrate spills. Chlorine concentration data from the hydrate spill tests compare favorably with calculations based on a quasi-steady area source dispersion model and empirical estimates of the hydrate decomposition rate. The theoretical dispersion model was combined with assumed hydrate spill probabilities and current motor vehicle accident statistics in order to project expected chlorine-induced fatality rates. These calculations indicate that expected chlorine fataility rates are several times higher in a city such as Los Angeles with a warm and calm climate than in a colder and windier city such as Boston. Calculated chlorine-induced fatality rate projections for various climates are presented as a function of hydrate spill probability in order to illustrate the degree of vehicle/battery crashworthiness required to maintain chlorine-induced fatality rates below current vehicle fatality rates due to fires and asphyxiations. 37 figures, 19 tables.

  4. Comparative efficacy of chlorine and chlorine dioxide regimes for condenser slime control in seawater cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, P.S.; Veeramani, P.; Ershath, M.; Rajamohan, R.; Harinath, Y.V.; Mohan, T.V.K.; Venugopalan, V.P. [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamil nadu (India)

    2010-07-01

    Chlorination has long been used as an effective and economic biocide for biofouling control in seawater cooling systems. However, the efficacy of chlorine is reduced in the presence of organic content of seawater and the inability of chlorine to effectively penetrate biofilms. Chlorine dioxide is being projected as a possible alternative to chlorine. Experiments were carried out with the help of a seawater circulating facility, in which direct comparison of the efficacy of the two biocides was possible using test condenser tube assemblies. The test condenser tubes made of titanium, SS 316L and Cu-Ni 90/10 were dosed with chlorine and chlorine dioxide. Each dose was evaluated for 30 days. Continuous and intermittent additions of chlorine (0.38 - 0.45 mg L{sup -1} TRO) and chlorine dioxide (0.4 - 0.5 mg L{sup -1}) were used, along with control. The flow velocity in the tubes was maintained at 1.5 m/s. Results of the study showed that the efficacy of the biocide to control biofilms depended on the biocide and the material. Continuous chlorination resulted in 75% reduction of viable counts on titanium, followed by 24% reduction on CuNi and 6% reduction on SS 316L surfaces, as compared to the control. When compared to continuous chlorination, increase in bacterial density in the tubes was observed at different regimes of intermittent chlorination. On SS 316L and Cu-Ni surfaces, intermittent chlorination for 1h, once every 3 h, appeared to give adequate protection. Continuous addition of chlorine dioxide resulted in 99% reduction of viable counts on titanium surfaces, followed by 28% reduction on SS 316 L surfaces and 52% reduction on Cu-Ni surfaces, as compared to the controls. The data indicate that the efficacy of biocides to control biofilms depend on not only the biocide and its frequency of application but also the material of construction. (author)

  5. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. In order to complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods.

  6. Behavioral toxicology, risk assessment, and chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista de Duffard, A.M.; Duffard, R. [Laboratorio de Toxicologia Experimental, Santa Fe (Argentina)

    1996-04-01

    Behavioral end points are being used with greater frequency in neurotoxicology to detect and characterize the adverse effects of chemicals on the nervous system. Behavioral measures are particularly important for neurotoxicity risk assessment since many known neurotoxicants do not result in neuropathology. The chlorinated hydrocarbon class consists of a wide variety of chemicals including polychlorinated biphenyls, clioquinol, trichloroethylene, hexachlorophene, organochlorine insecticides (DDT, dicofol, chlordecone, dieldrin, and lindane), and phenoxyherbicides. Each of these chemicals has effects on motor, sensory, or cognitive function that are detectable using functional measures such as behavior. Furthermore, there is evidence that if exposure occurs during critical periods of development, many of the chlorinated hydrocarbons are developmental neurotoxicants. Developmental neurotoxicity is frequently expressed as alterations in motor function or cognitive abilities or charges in the ontogeny of sensorimotor reflexes. Neurotoxicity risk assessment should include assessments of the full range of possible neurotoxicological effects, including both structural and functional indicators of neurotoxicity. 121 refs., 1 tab.

  7. A comparison of iodinated trihalomethane formation from chlorine, chlorine dioxide and potassium permanganate oxidation processes.

    Science.gov (United States)

    Zhang, Tian-Yang; Xu, Bin; Hu, Chen-Yan; Lin, Yi-Li; Lin, Lin; Ye, Tao; Tian, Fu-Xiang

    2015-01-01

    This study compared the formation of iodinated trihalomethanes (I-THMs) from iodide-containing raw waters oxidized by chlorine, chlorine dioxide (ClO₂) and potassium permanganate (KMnO₄) at different oxidant concentrations, reaction times, pHs, initial iodide concentrations and bromide to iodide mass ratios. Among the six investigated I-THMs, iodoform was the major species formed during the oxidation using chlorine, ClO₂ and KMnO₄. When oxidant concentration increased from 0.1 to 3.0 mg/L, the formation of I-THMs increased and then decreased for chlorine and ClO₂, but kept increasing for KMnO₄. As the reaction time went by, I-THM concentration increased to a plateau within 10 h (ClO₂ within only 1 h, especially) for all the three oxidants. I-THM formation gradually increased from pH 3.0 to 9.0 and remained stable at pH values higher than 7.5 for chlorine; however, for ClO₂ and KMnO₄ the highest I-THM formation showed at pH 7.0 and 7.5, respectively. As initial iodide concentration increased from 20 to 800 μg/L, the total amount and species of I-THMs increased for the three oxidants. Iodide contributed to I-THM formation much more significantly than bromide.

  8. The gas phase chlorination of ethane

    Energy Technology Data Exchange (ETDEWEB)

    Olsbye, Unni; Myhrvold, Elisabeth M.; Slagtern, Aase; Dahl, Ivar M. [SINTEF Applied Chemistry, Oslo (Norway)

    1999-07-01

    Light alkanes are dehydrogenated to their corresponding olefins before further reactions to more valuable chemicals. The conversion of ethane to ethene in a steam cracker requires the addition of a substantial amount of heat (90 kJ/mol). Oxidative processes for ethane dehydrogenation could in principle be carried out adiabatically, however, the oxidation selectivity towards hydrogen is too low in existing systems, which leads to low ethene selectivities. This paper discusses the potential for light alkane derivatization through chlorination.

  9. Thermal diffusion of chlorine in uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Y.; Toulhoat, N.; Moncoffre, N.; Jaffrezic, H.; Gavarini, S. [Inst. de Physique Nucleaire de Lyon (IPNL), Villeurbanne (France); Martin, P. [Commissariat a l' Energie Atomique (CEA), Centre de Cadarache, DEN/DEC/SESC/LLCC, Saint-Paul lez Durance (France); Raimbault, L. [Centre d' Informatique Geologique (CIG), Ecole des Mines, Fontainebleau (France); Scheidegger, A.M. [Lab. for Waste Management, Nuclear Energy and Safety Dept. (NES), Paul Scherrer Inst. Villigen PSI (Switzerland)

    2006-07-01

    In a nuclear reactor, isotopes such as {sup 35}Cl present as impurities in the nuclear fuel are activated by thermal neutron capture. During interim storage or geological disposal of nuclear fuel, the activation products such as {sup 36}Cl may be released from the fuel to the geo/biosphere and contribute to the ''instant release fraction'' as they are likely to migrate in defects and grain boundaries. In order to differentiate diffusion mechanisms due to ''athermal'' processes during irradiation from thermally activated diffusion, both irradiation and thermal effects must be assessed. This work concerns the measurement of the thermal diffusion coefficient of chlorine in UO{sub 2}. {sup 37}Cl was implanted at a 10{sup 13} at/cm{sup 2} fluence in depleted UO{sub 2} samples which were then annealed in the 900-1200 C temperature range and finally analyzed by secondary ion mass spectrometry (SIMS) to obtain {sup 37}Cl depth profiles. The migration process appears to be rather complex, involving mechanisms such as atomic, grain boundary, directed diffusion along preferential patterns as well as trapping into sinks before successive effusion. However, using a diffusion model based on general equation of transport, apparent diffusion coefficients could be calculated for 1000 and 1100 C and a mean activation energy of 4.3 eV is proposed. This value is one of the lowest values compared to those found in literature for other radionuclides pointing out a great ability of chlorine to migrate in UO{sub 2} at relatively low temperatures. In order to unequivocally determine the diffusion behaviour of both implanted and pristine chlorine before and after thermal annealing, the structural environment of chlorine in UO{sub 2} was examined using micro X-ray fluorescence (micro-XRF) and micro X-ray absorption spectroscopy (micro-XAS). (orig.)

  10. Self-assembly of long chain fatty acids: Effect of a methyl branch

    DEFF Research Database (Denmark)

    Liljeblad, Jonathan F. D.; Tyrode, Eric; Thormann, Esben

    2014-01-01

    chains of the straight chain fatty acids appear to be oriented perpendicular to the sample surface, based on an orientational analysis of VSFS data and the odd/even effect. In addition, the selection of the subphase (neat water or CdCl2 containing water buffered to pH 6.0) used for the LB-deposition has...... a profound influence on the monolayer morphology, packing density, compressibility, and conformational order. Finally, the orientation of the 19-MEA dimethyl moiety is estimated, and a strategy for performing an orientational analysis to determine the complete molecular orientation of the aliphatic chains...

  11. Hydraulic fracturing with chlorine dioxide cleanup

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.A.; Newlove, J.C.; Horton, R.L.

    1990-10-23

    This patent describes a method for fracturing a subterranean formation penetrated by a wellbore. It comprises: injecting a fracturing fluid into the formation to form a vertical fracture therein, the fracturing fluid being gelled with a polymer selected from guar, guar derivatives, acrylamide, acrylamide derivatives, cellulose, cellulose derivatives, and mixtures thereof and crosslinked with an organometallic crosslinking compound and having temperature stability above about 175{degrees} F.; packing the fracture with particulate propping agent; backflowing fluids from the formation through the propped fracture to remove a portion of the polymer; injecting at matrix rates sufficient aqueous solution of chlorine dioxide down the wellbore and into the propped fracture to penetrate at least 60 feet of the propped fracture length and contact polymer in the fracturing fluid and polymer residue in the propped fracture and on the fracture walls, the amount of the chlorine dioxide in the aqueous medium being sufficient to degrade polymer in the fracturing fluid and polymer residue; permitting the chlorine dioxide to remain in contact with the polymer in the fracturing fluid and with the polymer residue on the fracture walls and in the fracture for sufficient time to degrade the polymer thereby reducing the fracturing fluid viscosity and dissolving portions of the polymer residue; and flowing formation fluid from the formation through the propped fracture and into the wellbore to remove substantial portions of the polymer and degraded polymer from the fracture.

  12. Chlorine Monoxide in the Antarctic Spring Stratosphere.

    Science.gov (United States)

    Jaramillo-Ayerbe, Mauricio

    1988-06-01

    A series of observations of stratospheric chlorine monoxide (ClO) were carried out during the austral springs of 1986 and 1987 in McMurdo Station, Antarctica, as part of two experimental campaigns sent to investigate the seasonal decrease in ozone over the antarctic continent (the ozone "hole"). Measurements of the vertical distribution of ClO were obtained by high resolution ground-based emission spectroscopy at 278 GHz, using the Stony Brook mm-wave receiver. They show the presence of an anomalous layer of lower stratospheric ClO which is not observed at other latitudes. This anomalous layer is centered at ~20 km altitude and exhibits a pronounced diurnal variation, reaching a maximum at midday and disappearing at night. During the period of Sep. 20-24, 1987, the lower-stratospheric ClO had a maximum volume mixing ratio of 1.8_sp{+0cdot5}{ -0cdot9} ppbv. A normal ClO layer centered at ~36 km was also observed, with concentrations and diurnal behavior similar to those seen in tropical latitudes. These findings are evidence of anomalous chlorine chemistry taking place in the lower stratosphere during the antarctic spring, and indicate that increasing anthropogenic chlorine is a prime causative agent in the formation of the ozone hole.

  13. Electric plasma discharge combustion synthesis of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Dotson, R. L.; Geren, G. W.

    1984-09-18

    A process for the production of chlorine dioxide comprises feeding an inert gas to a reaction zone and applying an electrical discharge to the inert gas to produce a high temperature plasma. Chlorine gas and oxygen gas are supplied simultaneously to the reaction zone and reacted in the plasma to produce a gaseous mixture comprised of chlorine dioxide, chlorine, oxygen and inert gas, the molar ratio of oxygen to chlorine in the reaction zone being at least about 2.5;1. The gaseous mixture is recovered from the reaction zone. Chlorine dioxide, which may be recovered as a gas or reacted to produce an alkali metal chlorite, is employed as a bleaching agent and a water treatment agent.

  14. Method of improving formation permeability using chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, L.A.; Williams, D.A.

    1991-07-16

    This patent describes a method of treating a sandstone formation containing clays or silicates. It comprises injection a treating liquid into the formation comprising an aqueous solution of: from 50 to 4,200 ppm chlorine dioxide and from 1 to 85 volume percent of carbon dioxide; permitting the chlorine dioxide to react with material in the formation; and thereafter injecting into the formation an acid solution capable of dissolving the reaction products of chlorine dioxide and the clays and silicates.

  15. Treatment of algae-induced tastes and odors by chlorine, chlorine dioxide and permanganate

    OpenAIRE

    Buffin, Lisa Webster

    1992-01-01

    Chlorine (C12(sq»' chlorine dioxide (Cl02 ) and potassium permanganate (KMn04) were evaluated as oxidants for the removal of grassy and cucumber odors associated with the pure compounds, cis-3-hexenol and trans-2, cis-6-nonadienal, respectively, and for the removal of fishy odors associated with a culture of an alga, Synura petersenii. The effects of the oxidants on the pure compounds were assessed both by Flavor Profile Analysis (FPA) and gas chromatography/mass spectrometry (GC/MS). The ef...

  16. Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2-Arylbenzoxazoles%Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2-Arylbenzoxazoles

    Institute of Scientific and Technical Information of China (English)

    冷瑜婷; 杨帆; 吴养洁; 李克

    2011-01-01

    An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.

  17. Self-assembly of short peptides composed of only aliphatic amino acids and a combination of aromatic and aliphatic amino acids.

    Science.gov (United States)

    Subbalakshmi, Chilukuri; Manorama, Sunkara V; Nagaraj, Ramakrishnan

    2012-05-01

    The morphology of structures formed by the self-assembly of short N-terminal t-butyloxycarbonyl (Boc) and C-terminal methyl ester (OMe) protected and Boc-deprotected hydrophobic peptide esters was investigated. We have observed that Boc-protected peptide esters composed of either only aliphatic hydrophobic amino acids or aliphatic hydrophobic amino acids in combination with aromatic amino acids, formed highly organized structures, when dried from methanol solutions. Transmission and scanning electron microscopic images of the peptides Boc-Ile-Ile-OMe, Boc-Phe-Phe-Phe-Ile-Ile-OMe and Boc-Trp-Ile-Ile-OMe showed nanotubular structures. Removal of the Boc group resulted in disruption of the ability to form tubular structures though spherical aggregates were formed. Both Boc-Leu-Ile-Ile-OMe and H-Leu-Ile-Ile-OMe formed only spherical nanostructures. Dynamic light scattering studies showed that aggregates of varying dimensions were present in solution suggesting that self-assembly into ordered structures is facilitated by aggregation in solution. Fourier transform infrared spectroscopy and circular dichroism spectroscopy data show that although all four of the protected peptides adopt well-defined tertiary structures, upon removal of the Boc group, only H-Phe-Phe-Phe-Ile-Ile-OMe had the ability to adopt β-structure. Our results indicate that hydrophobic interaction is a very important determinant for self-assembly and presence of charged and aromatic amino acids in a peptide is not necessary for self-assembly.

  18. Biodegradation of aliphatic hydrocarbons in the presence of hydroxy cucurbit[6]uril.

    Science.gov (United States)

    Pasumarthi, Rajesh; Kumar, Vikash; Chandrasekharan, Sivaraman; Ganguly, Anasuya; Banerjee, Mainak; Mutnuri, Srikanth

    2014-11-15

    Aliphatic hydrocarbons are one of the major environmental pollutants with reduced bioavailability. The present study focuses on the effect of hydroxy cucurbit[6]uril on the bioavailability of hydrocarbons. A bacterial consortium was used for biodegradation studies under saline and non-saline conditions. Based on denaturing gradient gel electrophoresis results it was found that the consortium under saline conditions had two different strains. The experiment was conducted in microcosms with tetradecane, hexadecane, octadecane and mixture of the mentioned hydrocarbons as the sole carbon source. The residual hydrocarbon was quantified using gas chromatography every 24h. It was found that biodegradation of tetradecane and hexadecane, as individual carbon source increased in the presence of hydroxy CB[6], probably due to the increase in their bioavailability. In case of octadecane this did not happen. Bioavailability of all three aliphatic hydrocarbons was increased when provided as a mixture to the consortium under saline conditions.

  19. Aliphatic C-H---Anion Hydrogen Bonds: Weak Contacts or Strong Interactions?

    Energy Technology Data Exchange (ETDEWEB)

    Hay, Benjamin [ORNL; Pedzisa, Lee [ORNL

    2009-01-01

    Electronic structure calculations, MP2/aug-cc-pVDZ, are used to determine C H---Cl hydrogen bond energies for a series of XCH3 donor groups in which the electron-withdrawing ability of X is varied over a wide range of values. When attached to polarizing substituents, aliphatic CH groups are moderate to strong hydrogen bond donors, exhibiting interaction energies comparable to those obtained with O H and N H groups. The results explain why aliphatic C H donors are observed to function as competitive binding sites in solution and suggest that such C H---anion contacts should be considered as possible contributors when evaluating the denticity of an anion receptor.

  20. Preparation and Spectroscopic Study of Different Stoichiometric Solid Supramolecular Inclusion Complexes of β-Cyclodextrin with Short Chain Aliphatic Amines

    Institute of Scientific and Technical Information of China (English)

    Le-xin Song; Chuan-feng Teng; Hai-ming Wang; Lei Bai

    2008-01-01

    The solid Supramolecular complexes of β-cyclodextrin (β-CD) with ethylenediamine 1,diethylenetriamine 2 and triethylamine 3 were obtained and characterized using elemental analysis,powder X-ray diffraction, infrared spectroscopy,thermogravimetric analysis,and 1H nuclear magnetic resonance spectroscopy.Based on the results of elemental analysis and 1H NMR,the guest-host stoichiometries of the three solid complexes were determined to be 5:2 for 1-β-CD,1:1 for 2-β-CD,and 1:3 for 3-β-CD.The yields were relative to the molar volume ratio of guest to β-CD cavity,and increased in the order:1-β-CD<2-β-CD<3-β-CD.X-ray diffraction patterns of the inclusion complexes gave very good exhibitions not only in location of diffraction peaks but also in shape and diffraction intensity of the peaks due to the intermolecular complexations between β-CD and the guests.The formation of host-guest inclusion complexes exhibited obviously enhanced phase change temperatures of the complexed guests such as 1 and 3.The H-5 protons located at the narrower rim inside the CD cavity experienced a higher shift upon inclusion while all other protons experienced lower shifts.

  1. Integrated evaluation of the performance of a more than seven year old permeable reactive barrier at a site contaminated with chlorinated aliphatic hydrocarbons (CAHs)

    DEFF Research Database (Denmark)

    Muchitsch, Nanna; Nooten, Thomas Van; Bastiaens, Leen;

    2011-01-01

    An important issue of concern for permeable reactive iron barriers is the long-term efficiency of the barriers due to the long operational periods required. Mineral precipitation resulting from the anaerobic corrosion of the iron filings and bacteria present in the barrier may play an important r...

  2. Synthesis and characterization of novel main chain bisazobenzene polyphosphonates

    Science.gov (United States)

    Vlad-Bubulac, Tǎchiţǎ; Serbezeanu, Diana; Carja, Ionela-Daniela

    2016-12-01

    Preparation and experimental studies on the phase transition and morphology of novel phosphorus-containing copolymers, having bisazobenzene units and variable molar ratio of aliphatic segments in the main chain, were performed. The chemical structure of the novel compounds has been confirmed by Fourier transform infrared and 1H-NMR spectroscopy. The thermal stability was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) while the mesomorphic behavior was closely observed with polarized light microscope (PLM) and by X-ray diffraction measurements, structure-properties relationships being established and discussed.

  3. Synthesis and antiproliferative activity of aromatic and aliphatic bis[aminomethylidene(bisphosphonic)] acids.

    Science.gov (United States)

    Goldeman, Waldemar; Nasulewicz-Goldeman, Anna

    2014-08-01

    A series of aromatic and aliphatic bis[aminomethylidene(bisphosphonic)] acids was synthesized in the reaction of triethylphosphite with isonitriles followed by hydrolysis or dealkylation. The in vitro anti-proliferative effect of all synthesized tetraphosphonic acids against MCF-7 breast cancer cells, J774E macrophages and HL-60 promyelocytic leukemia cells was determined. Three aromatic derivatives (5a, 5f and 5j) showed a similar or higher anti-proliferative activity than zoledronic acid.

  4. PcMtr, an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum

    OpenAIRE

    Trip, H; EVERS, ME; Driessen, AJM

    2004-01-01

    The gene encoding an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum was cloned, functionally expressed and characterized in Saccharomyces cerevisiae M4276. The permease, designated PcMtr, is structurally and functionally homologous to Mtr of Neurospora crassa, and unrelated to the Amino Acid Permease (AAP) family which includes most amino acid permeases in fungi. Database searches of completed fungal genome sequences reveal that Mtr type permeases are not widely...

  5. Synthetic resveratrol aliphatic acid inhibits TLR2-mediated apoptosis and an involvement of Akt/GSK3beta pathway.

    Science.gov (United States)

    Chen, Lin; Zhang, Yi; Sun, Xiuli; Li, Hui; LeSage, Gene; Javer, Avani; Zhang, Xiumei; Wei, Xinbing; Jiang, Yulin; Yin, Deling

    2009-07-01

    As resveratrol derivatives, resveratrol aliphatic acids were synthesized in our laboratory. Previously, we reported the improved pharmaceutical properties of the compounds compared to resveratrol, including better solubility in water and much tighter binding with human serum albumin. Here, we investigate the role of resveratrol aliphatic acids in Toll-like receptor 2 (TLR2)-mediated apoptosis. We showed that resveratrol aliphatic acid (R6A) significantly inhibits the expression of TLR2. In addition, overexpression of TLR2 in HEK293 cells caused a significant decrease in apoptosis after R6A treatment. Moreover, inhibition of TLR2 by R6A decreases serum deprivation-reduced the levels of phosphorylated Akt and phosphorylated glycogen synthase kinase 3beta (GSK3beta). Our study thus demonstrates that the resveratrol aliphatic acid inhibits cell apoptosis through TLR2 by the involvement of Akt/GSK3beta pathway.

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

    Science.gov (United States)

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-11-10

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

  7. Tapetum Degeneration Retardation is Critical for Aliphatic Metabolism and Gene Regulation during Rice Pollen Development

    Institute of Scientific and Technical Information of China (English)

    Da-Sheng Zhang; Wan-Qi Liang; Zheng Yuan; Na Li; Jing Shi; Jue Wang; Yu-Min Liu; Wen-Juan Yu; Da-Bing Zhang

    2008-01-01

    As a complex wall system in flowering plants,the pollen outer wall mainly contains aliphatic sporopollenin;however,the mechanism for synthesizing these lipidic precursors during pollen development remains less well under-stood.Here,we report on the function of the rice tapetum-expressing TDR(Tapetum Degeneration Retardation)gene in aliphatic metabolism and its regulatory role during rice pollen development.The observations of transmission electron microscopy (TEM) and scanning electron microscopy(SEM)analyses suggested that pollen wall formation was significantly altered in the tdr mutant.The contents of aliphatic compositions of anther were greatly changed in the tdr mutant revealed by GC-MS(gas chromatography-mass spectrometry)testing,particularly less accumulated in fatty acids, primary alcohols,alkanes and alkenes,and an abnormal increase in secondary alcohols with carbon Iengths from C29 to C35 in tdr.Microarray data revealed that a group of genes putatively involved in lipid transport and metabolism were significantly altered in the tdr mutant,indicating the critical role of TDR in the formation of the pollen wall.Also,a wide range of genes tween wild-type and tdr.In addition to its function in promoting tapetum PCD,TDR possibly plays crucial regulatory roles in several basic biological processes during rice pollen development.

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

    Science.gov (United States)

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

    2016-05-01

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

  9. Chlorinated and nitrogenous disinfection by-product formation from ozonation and post-chlorination of natural organic matter surrogates.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Rifai, Omar; Ali, Hussain; Graham, Nigel J D

    2014-09-01

    Ozonation before chlorination is associated with enhanced formation of chloropicrin, a halonitromethane disinfection by-product (DBP), during drinking water treatment. In order to elucidate reasons for this, five natural organic matter (NOM) surrogates were treated using both chlorination and ozonation-chlorination under controlled laboratory conditions. Selected surrogates comprised two phenolic compounds, two free amino acids and one dipeptide; these were resorcinol, 3-aminophenol, L-aspartic acid, β-alanine and ala-ala, respectively. Quantified DBPs included chloropicrin, chloroform, dichloroacetonitrile and trichloroacetonitrile. Relative to chlorination alone, increases in the formation of chloropicrin from ozonation-chlorination varied from 138% for 3-aminophenol to 3740% for ala-ala for the four amine surrogates. This indicates that ozone is more effective than chlorine in mediating a rate-limiting oxidation step in chloropicrin formation, most plausibly involving conversion of an amine group to a nitro group. While both hydrophilic and hydrophobic surrogates acted as chloropicrin precursors, ala-ala was the most reactive precursor following ozonation-chlorination. Since peptides are far commoner in drinking water sources than free amino acids, further research into chemical oxidation of these species by ozone and chlorine is recommended. In contrast, oxidation with ozone prior to chlorination reduced chloroform formation moderately for the two phenolic compounds.

  10. Synthesis and Characterization of Long-Chain Tartaric Acid Diamides as Novel Ceramide-Like Compounds

    Directory of Open Access Journals (Sweden)

    Krisztina Takács-Novák

    2010-02-01

    Full Text Available Ceramides play a crucial role in the barrier function of the skin as well as in transmembrane signaling. In this study long aliphatic chain tartaric acid diamides able to replace ceramides in an in vitro model of the stratum corneum lipid matrix due to their similar physico-chemical properties were synthesized from diacetoxysuccinic anhydride in four steps. Their pro-apoptotic effect on fibroblast cells was also investigated.

  11. Effects of chlorine and chlorine dioxide on mutagenic activity of Lake Kinnereth water

    Energy Technology Data Exchange (ETDEWEB)

    Guttman-Bass, N.; Bairey-Albuquerque, M.; Ulitzur, S.; Chartrand, A.; Rav-Acha, C.

    1987-03-01

    Water from Lake Kinnereth (Israel) was tested for the presence of mutagenic activity, with and without disinfection by chlorine and chlorine dioxide. The samples were assayed for activity with two Ames Salmonella typhimurium tester strains, TA 104 and TA 100, and by a luminescent genotoxic assay with a dark mutant strain of Photobacterium fischeri. The water concentrates were mutagenic in strain TA 104 and in the luminescent assay, reaching positive mutagenic activities in the equivalent of 20 mL of water. Chlorination did not greatly affect the net mutagenic activity, although ClO/sub 2/ apparently reduced it. Humic acids were isolated from lake sediment and were assayed with and without disinfection in distilled water and in lake water from which the organic components were removed. The humic acids were mutagenic in both test systems, and treatment with Cl/sub 2/ generally decreased the net activity. ClO/sub 2/ also tended to decrease the mutagenic activity, and cytotoxic effects were observed in some of the samples. Conversely, commercial humic acid was mutagenic only after chlorination on strain TA 100. 54 references, 3 figures, 6 tables.

  12. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    Science.gov (United States)

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii. PMID:21602398

  13. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Michael J. Truex; Charles J. Newell; Brian Looney

    2007-02-28

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  14. Advantages and disadvantages of chemical oxidation and disinfection by ozone and chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F.; Richard, Y.; Montiel, A.; Musquere, P.

    1981-04-01

    Ozone and chlorine dioxide present definite advantages and disadvantages over chlorination. Chlorination, particularly for the removal of ammonia and the maintenance of a disinfectant residual in the distribution system has decisive advantages and will be difficult to replace. Ozone and chlorine dioxide seem to produce fewer carcinogenic by-products but the risk for acute toxicity, especially from the chlorites which follow chlorine dioxide, is higher than with chlorine. Chlorine dioxide and more particularly ozone should be considered as useful complements to chlorination, but no strong oxidative treatment should be applied before most of the organic matter has been removed.

  15. PEGylated and Functionalized Aliphatic Polycarbonate Polyplex Nanoparticles for Intravenous Administration of HDAC5 siRNA in Cancer Therapy.

    Science.gov (United States)

    Frère, Antoine; Baroni, Alexandra; Hendrick, Elodie; Delvigne, Anne-Sophie; Orange, François; Peulen, Olivier; Dakwar, George R; Diricq, Jérôme; Dubois, Philippe; Evrard, Brigitte; Remaut, Katrien; Braeckmans, Kevin; De Smedt, Stefaan C; Laloy, Julie; Dogné, Jean-Michel; Feller, Georges; Mespouille, Laetitia; Mottet, Denis; Piel, Géraldine

    2017-01-25

    Guanidine and morpholine functionalized aliphatic polycarbonate polymers are able to deliver efficiently histone deacetylase 5 (HDAC5) siRNA into the cytoplasm of cancer cells in vitro leading to a decrease of cell proliferation were previously developed. To allow these biodegradable and biocompatible polyplex nanoparticles to overcome the extracellular barriers and be effective in vivo after an intravenous injection, polyethylene glycol chains (PEG750 or PEG2000) were grafted on the polymer structure. These nanoparticles showed an average size of about 150 nm and a slightly positive ζ-potential with complete siRNA complexation. Behavior of PEGylated and non-PEGylated polyplexes were investigated in the presence of serum, in terms of siRNA complexation (fluorescence correlation spectroscopy), size (dynamic light scattering and single-particle tracking), interaction with proteins (isothermal titration calorimetry) and cellular uptake. Surprisingly, both PEGylated and non-PEGylated formulations presented relatively good behavior in the presence of fetal bovine serum (FBS). Hemocompatibility tests showed no effect of these polyplexes on hemolysis and coagulation. In vivo biodistribution in mice was performed and showed a better siRNA accumulation at the tumor site for PEGylated polyplexes. However, cellular uptake in protein-rich conditions showed that PEGylated polyplex lost their ability to interact with biological membranes and enter into cells, showing the importance to perform in vitro investigations in physiological conditions closed to in vivo situation. In vitro, the efficiency of PEGylated nanoparticles decreases compared to non-PEGylated particles, leading to the loss of the antiproliferative effect on cancer cells.

  16. 78 FR 66767 - Chlorinated Isocyanurates From China and Japan

    Science.gov (United States)

    2013-11-06

    ... publishing the notice in the Federal Register of September 10, 2013 (78 FR 55293). The conference was held in... COMMISSION Chlorinated Isocyanurates From China and Japan Determinations On the basis of the record \\1... injured by reason of imports from China and Japan of chlorinated isocyanurates, provided for...

  17. Experimental and Theoretical Studies of Atmosphereic Inorganic Chlorine Chemistry

    Science.gov (United States)

    Sander, Stanley P.; Friedl, Randall R.

    1993-01-01

    Over the last five years substantial progress has been made in defining the realm of new chlorine chemistry in the polar stratosphere. Application of existing experimental techniques to potentially important chlorine-containing compounds has yielded quantitative kinetic and spectroscopic data as well as qualitative mechanistic insights into the relevant reactions.

  18. Chlorine Dioxide Induced Multiple Chemical Sensitivity: MMPI Validity Problems.

    Science.gov (United States)

    Tentoni, Stuart C.

    This paper discusses Minnesota Multiphasic Personality Inventory (MMPI) data obtained from individuals exposed to chlorine dioxide in the workplace who developed Multiple Chemical Sensitivity Syndrome. The paper explores current research on chlorine dioxide exposed persons who were misdiagnosed on the basis of MMPI interpretations. Difficulties…

  19. 75 FR 23303 - Chlorinated Isocyanurates From China and Spain

    Science.gov (United States)

    2010-05-03

    ... COMMISSION Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade... isocyanurates from China and Spain. SUMMARY: The Commission hereby gives notice that it has instituted reviews... revocation of the antidumping duty orders on chlorinated isocyanurates from China and Spain would be...

  20. 75 FR 51113 - Chlorinated Isocyanurates From China and Spain

    Science.gov (United States)

    2010-08-18

    ... COMMISSION Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade... chlorinated isocyanurates from China and Spain. SUMMARY: The Commission hereby gives notice of the scheduling... from China and Spain would be likely to lead to continuation or recurrence of material injury within...

  1. Chlorine-containing natural compounds in higher plants

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1986-01-01

    More than 130 chlorine-containing compounds have been isolated from higher plants and ferns; about half are polyacetylenes, thiophenes and sesquiterpene lactones from the Asteraceae. A chlorinated chlorophyll may be an important part of photosystem 1. High biological activity is found in 4...

  2. Low-Cost Graphite-Based Free Chlorine Sensor.

    Science.gov (United States)

    Pan, Si; Deen, M Jamal; Ghosh, Raja

    2015-11-01

    Pencil lead was used to fabricate a graphite-based electrode for sensing applications. Its surface was electrochemically modified using ammonium carbamate to make it suitable for sensing free chlorine in water samples. Chlorine is widely used as a disinfectant in the water industry, and the residual free chlorine concentration in water distributed to the consumers must be lower than that stipulated by regulatory bodies. The graphite-based amperometric sensor gave a selective and linear response to free chlorine in the relevant concentration range and no response to commonly interfering ions. It was evaluated further for storage stability, response time, and hysteresis. This sensor is being proposed as a low-cost device for determining free chlorine in water samples. Its ease-of-use, limitations, and feasibility for mass-production and application is discussed.

  3. Biodegradability of Chlorinated Anilines in Waters

    Institute of Scientific and Technical Information of China (English)

    CHAO WANG; GUAN-GHUA LU; YAN-JIE ZHOU

    2007-01-01

    Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes,Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.

  4. Synergetic Inactivation of Microorganisms in Drinking Water by Short-term Free Chlorination and Subsequent Monochloramination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli,Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

  5. Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

    Science.gov (United States)

    Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

    2017-06-01

    The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × timereaction) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, Ea, induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (CODMn) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and CODMn concentrations contributed to the inactivation of T. tubifex.

  6. Change in genotoxicity of wastewater during chlorine dioxide and chlorine disinfections and the influence of ammonia nitrogen

    Institute of Scientific and Technical Information of China (English)

    WANG Lisha; HU Hongying; WANG Chao; Koichi Fujie

    2007-01-01

    The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test.The experiment results showed that when chlorine dioxide dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater first decreased rapidly and then tended to be stable,while when the chlorine dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater changed diversely for different samples.It was then found that ammonia nitrogen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater,while it greatly affected the change of genotoxicity during chlorine disinfection of wastewater.When the concentration of ammonia nitrogen was low(<10-20mg/L),the genotoxicity of wastewater decreased after chlorine disinfection,and when the concentration of ammonia nitrogen was high(>10-20 mg/L),the genotoxicity of wastewater increased after chlorine disinfection.

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

    Science.gov (United States)

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

    2015-05-01

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

  8. U-shaped conformation of alkyl chains bound to a synthetic receptor cucurbit[8]uril.

    Science.gov (United States)

    Ko, Young Ho; Kim, Youngkook; Kim, Hyunuk; Kim, Kimoon

    2011-02-01

    The behavior of a series of alkanes bound to the molecular host cucurbit[8]uril (CB[8]) has been systematically studied by 2D (1)H NMR spectroscopy and isothermal titration calorimetry (ITC). CB[8] and alkyltrimethylammonium (C(m) TA(+), (CH(3))(3)N(+)C(m)H(2m+1), m=6-16) form 1:1 host-guest complexes with a high binding constant (K≈10(6) m(-1)). The shortest hexyl chain of C(6)TA(+) can be fully encapsulated in an extended conformation inside the CB[8] cavity, which is driven by both enthalpy and entropy. However, for the longer aliphatic chains, C(8)-C(16), the long alkyl tails take a U-shaped conformation inside the cavity, and their complexation is dominantly or almost exclusively enthalpy-driven, owing to the increased van der Waals contact between the folded aliphatic chain and the inner wall of the host cavity. As the chain length increases from C(8) to C(16), the ammonium head group of the guests moves away from the portal of CB[8] while the long aliphatic tails maintain the U-shaped conformation inside the cavity. The complexation of C(m)TA(+) with CB[8] follows the enthalpy-entropy compensation rule commonly observed in molecular recognition systems. For example, among the guest molecules, C(12)TA(+) shows the highest enthalpic gain (most favorable), owing to the large van der Waals contact between the guest and the host cavity, and at the same time the most unfavorable entropic contribution, owing to the severe conformational restriction of the U-shaped alkyl chain inside the host. The enthalpy-entropy compensation plot for the complexation suggests large conformational changes of the long alkyl chains and extensive dehydration associated with the inclusion complex formation.

  9. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

    Time-resolved mass spectrometry and time-resolved photoelectron spectroscopy are used to study the ultrafast photodissociation dynamics of chlorine dioxide, an important constituent in stratospheric ozone depletion. Chapter 1 introduces these pump/probe techniques, in which a femtosecond pump pulse excites a molecule to a dissociative state. At a later time, a second femtosecond probe pulse ionizes the molecule. The resulting mass and photoelectron spectra are acquired as a function of the delay between the pump and probe pulses, which follows the evolution of the molecule on the excited state. A comparison to other techniques used to study reaction dynamics is discussed. Chapter 2 includes a detailed description of the design and construction of the experimental apparatus, which consists of a femtosecond laser system, a molecular beam time-of-flight spectrometer, and a data acquisition system. The time-of-flight spectrometer is specifically designed to have a short flight distance to maximize the photoelectron collection efficiency without degrading the resolution, which is limited by the bandwidth of the femtosecond laser system. Typical performance of the apparatus is demonstrated in a study of the time-resolved photoelectron spectroscopy of nitric oxide. The results of the time-resolved mass spectrometry experiments of chlorine dioxide are presented in Chapter 3. Upon excitation to the A {sup 2}A{sub 2} state near 3.2 eV, the molecule dissociates through an indirect two-step mechanism. The direct dissociation channel has been predicted to be open, but is not observed. A quantum beat is observed in the OClO{sup +} species, which is described as a vibrational coherence of the optically prepared A {sup 2}A{sub 2} state. Chapter 4 presents the results of the time-resolved photoelectron experiments of chlorine dioxide. At short delay time, the quantum beat of the OClO{sup +} species is observed in the X {sup 1}A{sub 1} state of the ion. At infinite delay, the signal

  10. Impact of vegetation and ecosystems on chlorine(-36) cycling and its modeling: from simplified approaches towards more complex biogeochemical tools

    Science.gov (United States)

    Thiry, Yves; Redon, Paul-Olivier; Gustafsson, Malin; Marang, Laura; Bastviken, David

    2013-04-01

    Chlorine is very soluble at a global scale with chloride (Cl-), the dominating form. Because of its high mobility, chlorine is usually perceived as a good conservative tracer in hydrological studies and by analogy as little reactive in biosphere. Since 36Cl can be considered to have the same behaviour than stable Cl, a good knowledge of chlorine distribution between compartments of terrestrial ecosystems is sufficient to calibrate a specific activity model which supposes rapid dilution of 36Cl within the large pool of stable Cl and isotopic equilibrium between compartments. By assuming 36Cl redistribution similar to that of stable Cl at steady-state, specific activity models are simplified interesting tools for regulatory purposes in environmental safety assessment, especially in case of potential long term chronic contamination of agricultural food chain (IAEA, 2010). In many other more complex scenarios (accidental acute release, intermediate time frame, and contrasted natural ecosystems), new information and tools are necessary for improving (radio-)ecological realism, which entails a non-conservative behavior of chlorine. Indeed observed dynamics of chlorine in terrestrial ecosystems is far from a simple equilibrium notably because of natural processes of organic matter (SOM) chlorination mainly occurring in surface soils (Öberg, 1998) and mediated by microbial activities on a large extent (Bastviken et al. 2007). Our recent studies have strengthened the view that an organic cycle for chlorine should now be recognized, in addition to its inorganic cycle. Major results showed that: organochlorine (Clorg) formation occurs in all type of soils and ecosystems (culture, pasture, forest), leading to an average fraction of the total Cl pool in soil of about 80 % (Redon et al., 2012), chlorination in more organic soils over time leads to a larger Clorg pool and in turn to a possible high internal supply of inorganic chlorine (Clin) upon dechlorination. (Gustafsson et

  11. Preparation of Novel Side-chain Pseudopolyrotaxanes Consisting of Cucurbituril[6] and Polyamine Salts

    Institute of Scientific and Technical Information of China (English)

    Zhao Sheng HOU; Ye Bang TAN; Kimoon KIM; Qi Feng ZHOU

    2005-01-01

    Pseudorotaxane monomer (VBCB) containing cucurbitutil[6] (CB[6]) and N1-(4-vinylbenzyl)-1,4-diaminobutane dihydrochloride (VBDADC) is obtained by self-assembly of cucurbituril[6] with VBDADC in water and then polymerized using potassium persulfate (KPS) as initiator to give novel water-soluble side-chain cucurbituril[6]-based pseudopolyr1o taxane (PVBCB). The chemical structures of PVBCB, VBCB and VBDADC are confirmed by H NMR,13C NMR spectra and elemental analysis. In VBCB, CB[6] is localized aliphatic group of the side chain and the molar ratio of CB[6] to VBDAC is 1:1.

  12. Biodegradation of Variable-Chain-Length Alkanes at Low Temperatures by a Psychrotrophic Rhodococcus sp.

    OpenAIRE

    Whyte, Lyle G; Hawari, Jalal; Zhou, Edward; Bourbonnière, Luc; Inniss, William E.; Charles W Greer

    1998-01-01

    The psychrotroph Rhodococcus sp. strain Q15 was examined for its ability to degrade individual n-alkanes and diesel fuel at low temperatures, and its alkane catabolic pathway was investigated by biochemical and genetic techniques. At 0 and 5°C, Q15 mineralized the short-chain alkanes dodecane and hexadecane to a greater extent than that observed for the long-chain alkanes octacosane and dotriacontane. Q15 utilized a broad range of aliphatics (C10 to C21 alkanes, branched alkanes, and a substi...

  13. Degradation of DEET and Caffeine under UV/Chlorine and Simulated Sunlight/Chlorine Conditions.

    Science.gov (United States)

    Sun, Peizhe; Lee, Wan-Ning; Zhang, Ruochun; Huang, Ching-Hua

    2016-12-20

    Photoactivation of aqueous chlorine could promote degradation of chlorine-resistant and photochemically stable chemicals accumulated in swimming pools. This study investigated the degradation of two such chemicals, N,N-diethyl-3-methylbenzamide (DEET) and caffeine, by low pressure ultraviolet (UV) light and simulated sunlight (SS) activated free chlorine (FC) in different water matrices. Both DEET and caffeine were rapidly degraded by UV/FC and SS/FC but exhibited different kinetic behaviors. The degradation of DEET followed pseudo-first-order kinetics, whereas the degradation of caffeine accelerated with reaction. Mechanistic study revealed that, under UV/FC, ·OH and Cl· were responsible for degradation of DEET, whereas ClO· related reactive species (ClOrrs), generated by the reaction between FC and ·OH/Cl·, played a major role in addition to ·OH and Cl· in degrading caffeine. Reaction rate constants of DEET and caffeine with the respective radical species were estimated. The imidazole moiety of caffeine was critical for the special reactivity with ClOrrs. Water matrix such as pH had a stronger impact on the UV/FC process than the SS/FC process. In saltwater matrix under UV/FC and SS/FC, the degradation of DEET was significantly inhibited, but the degradation of caffeine was much faster than that in nonsalty solutions. The interaction between Br(-) and Cl(-) may play an important role in the degradation of caffeine by UV/FC in saltwater. Reaction product analysis showed similar product patterns by UV/FC and SS/FC and minimal formation of chlorinated intermediates and disinfection byproducts.

  14. Does Chlorination of Seawater Reverse Osmosis Membranes Control Biofouling?

    KAUST Repository

    Khan, Muhammad Tariq

    2015-04-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full–scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  15. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Y. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France) and Universite Claude Bernard Lyon-1, Institut Universitaire de Technologie (IUT A), 94, boulevard Niels Bohr, 69622 Villeurbanne cedex (France)]. E-mail: pipon@ipnl.in2p3.fr; Bererd, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Universite Claude Bernard Lyon-1, Institut Universitaire de Technologie (IUT A), 94, boulevard Niels Bohr, 69622 Villeurbanne cedex (France); Moncoffre, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Peaucelle, C. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Toulhoat, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Commissariat a l' Energie Atomique (CEA), DEN/Saclay, 91191 Gif sur Yvette cedex (France); Jaffrezic, H. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Raimbault, L. [Ecole des Mines de Paris, Centre de Geosciences, 35 rue Saint Honore, F-77305 Fontainebleau cedex (France); Sainsot, P. [Institut National des Sciences Appliquees de Lyon (INSA), UMR 5514, F-69621 Villeurbanne cedex (France); Carlot, G. [Commissariat a l' Energie Atomique (CEA), Centre de Cadarache, DEN/DEC/SESC/LLCC, 13108 Saint-Paul lez Durance (France)

    2007-04-15

    The radiation enhanced diffusion of chlorine in UO{sub 2} during heavy ion irradiation is studied. In order to simulate the behaviour of {sup 36}Cl, present as an impurity in UO{sub 2}, {sup 37}Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV {sup 127}I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 x 10{sup -14} cm{sup 2} s{sup -1}, reflect the high mobility of chlorine in UO{sub 2} during irradiation with fission products.

  16. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Science.gov (United States)

    Pipon, Y.; Bérerd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrézic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

    2007-04-01

    The radiation enhanced diffusion of chlorine in UO2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36Cl, present as an impurity in UO2, 37Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 × 10-14 cm2 s-1, reflect the high mobility of chlorine in UO2 during irradiation with fission products.

  17. Does chlorination of seawater reverse osmosis membranes control biofouling?

    Science.gov (United States)

    Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

    2015-07-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  18. Removal effect on Mesocyclops leukarti and mutagenicity with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    ZUO Jin-long; CUI Fu-yi; QU Bo; ZHU Gui-bing

    2006-01-01

    Mesocyclops leukarti of zooplankton propagates excessively in eutrophic water body and it cannot be effectively inactivated by the conventional drinking water treatment process. In order to tackle this problem, a study of removal effect on Mesocyclops leukarti with chlorine dioxide in a waterworks was performed. The results showed that Mesocyclops leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation combined with the conventional drinking water treatment process.Higher oxidizability and molecular state of chlorine dioxide in water is the key to the inactivation of Mesocyclops leukarti. The chlorite, disinfection by-products (DBPs) of chlorine dioxide, was stable at 0.45 mg/L, which is lower than that critical value of the USEPA. GC-MS examination showed that the quantity of organic substance in the water treated by chlorine dioxide obviously decreased. Ames test further revealed that the mutagenicity was reduced by chlorine dioxide with respect to prechlorine. The propagation ofMesocyclops leukarti can be inactivated effectively and safely by chlorine dioxide pre-oxidation.

  19. Simultaneous determination of aliphatic hydrocarbons, PCBs and PCTs in pork liver by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Barros, C. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Alvarez Pineiro, M.E. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Simal Lozano, J. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Lage Yusty, M.A. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain)

    1996-10-01

    A multicomponent extraction/concentration procedure has been developed for the enrichment of PCBs, PCTs and aliphatic hydrocarbons (pristane, C{sub 18}, C{sub 19}, C{sub 20}, C{sub 22}, C{sub 24}, C{sub 28}, C{sub 32} and C{sub 36}) in pork liver. These components of the enriched extract were then simultaneously determined by gas chromatography. Mean recoveries ranged from 81.5% for pristane to 93% for PCBs; CV % (0.9-6.7) indicated the method to be both precise and reproducible. (orig.)

  20. Metal complexes of Schiff bases derived from dicinnamoylmethane and aliphatic diamines

    Directory of Open Access Journals (Sweden)

    K. KRISHNANKUTTY

    2008-04-01

    Full Text Available (Received 26 July, revised 10 December 2007Two new Schiff bases containing olefinic linkages have been synthesized by condensing aliphatic diamines with dicinnamoylmethane under specified conditions. The existence of these compounds predominantly in the intramolecularly hydrogen bonded keto-enamine form was well demonstrated by their IR, 1H-NMR and mass spectral data. Dibasic tetradentate N2O2 coordination of the compounds in their [ML] complexes (M = Ni(II, Cu(II and Zn(II was established on the basis of analytical and spectral data.

  1. Bifunctional Catalysis: Direct Reductive Amination of Aliphatic Ketones with an Iridium-Phosphate Catalyst

    Directory of Open Access Journals (Sweden)

    Barbara Villa-Marcos

    2010-04-01

    Full Text Available Chiral amines are one of the ubiquitous functional groups in fine chemical, pharmaceutical and agrochemical products, and the most convenient, economical, and eco-benign synthetic pathway to these amines is direct asymmetric reductive amination (DARA of prochiral ketones. This paper shows that a wide range of aliphatic ketones can be directly aminated under hydrogenation conditions, affording chiral amines with good to excellent yields and with enantioselectivities up to 96% ee. The catalysis is effected by the cooperative action of a cationic Cp*Ir(III complex and its phosphate counteranion.

  2. A QSPR STUDY OF NORMAL BOILING POINT OF ORGANIC COMPOUNDS (ALIPHATIC ALKANES USING MOLECULAR DESCRIPTORS

    Directory of Open Access Journals (Sweden)

    B. Souyei

    2013-12-01

    Full Text Available A quantitative structure–property relationship (QSPR study is carried out to develop correlations that relate the molecular structures of organic compounds (Aliphatic Alkanes to their normal boiling point (NBP and two correlations were proposed for constitutionals and connectivity indices Models. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate NBP. Such calculation gives us a model that gives results in remarkable correlations with the descriptors of blokes constitutionals (CON, and connectivity indices (CI (R2 = 0.950, δ = 0.766 (R2 = 0.969, δ = 0.782 respectively.

  3. A Study of Substituted Aliphatic Sulphides on the Corrosion Behaviour of Zinc in Ammonium Chloride Solution

    Directory of Open Access Journals (Sweden)

    R. Venckatesh

    2007-01-01

    Full Text Available Sulphur containing organic compounds decreases the corrosion rate by increasing the hydrogen over potential on zinc metal due to their electron donating groups. Their inhibiting effect was found to be associated with their adsorption on the active centers of the metal. The inhibition efficiencies of some aliphatic sulphides in ammonium chloride solution have been studied by weight loss studies, polarization and impedance measurements. The effect of substituent groups is correlated with their inhibition performance. These studies due to their relevance in Zn-Manganese dry batteries assume their importance.

  4. Abilities of some higher plants to hydrolyze the acetates of phenols and aromatic-aliphatic alcohols

    Directory of Open Access Journals (Sweden)

    Agnieszka Mironowicz

    2014-01-01

    Full Text Available In the biotransformations carried out under the same conditions, the whole intact plants of Spirodela punctata, Nephrolepis exaltata, Cyrtomium falcatum, Nephrolepis cordifolia and the suspension cultures of Helianthus tuberosus, Daucus carota and Petunia hybrida hydrolyze (partially or totally the ester bonds of the acetates of phenols and aromatic-aliphatic alcohols and also the menthyl acetate. Nevertheless, the methyl esters of aromatic acids, structurally similar to the former substrates, do not undergo hydrolysis. At the same time, the viability of first four plants was observed for different levels of acetate concentration. The method of continuous preparative hydrolysis of the same acetates was worked out in Cyrtomium falcatum culture.

  5. Silver-catalyzed decarboxylative alkynylation of aliphatic carboxylic acids in aqueous solution.

    Science.gov (United States)

    Liu, Xuesong; Wang, Zhentao; Cheng, Xiaomin; Li, Chaozhong

    2012-09-05

    C(sp(3))-C(sp) bond formations are of immense interest in chemistry and material sciences. We report herein a convenient, radical-mediated and catalytic method for C(sp(3))-C(sp) cross-coupling. Thus, with AgNO(3) as the catalyst and K(2)S(2)O(8) as the oxidant, various aliphatic carboxylic acids underwent decarboxylative alkynylation with commercially available ethynylbenziodoxolones in aqueous solution under mild conditions. This site-specific alkynylation is not only general and efficient but also functional group compatible. In addition, it exhibits remarkable chemo- and stereoselectivity.

  6. "Clip" and "click" chemistries combination: toward easy PEGylation of degradable aliphatic polyesters.

    Science.gov (United States)

    Freichels, Hélène; Pourcelle, Vincent; Le Duff, Cécile S; Marchand-Brynaert, Jacqueline; Jérôme, Christine

    2011-04-04

    α-Methoxy-ω-alkyne poly(ethylene glycol) (PEG) was tagged with pendent N-hydroxy-succinimidyl activated esters by photografting of a molecular clip. This easily synthesized heterofunctional PEG was found to be a versatile building block for (i) conjugation with an amino derivative and (ii) grafting to azido functional aliphatic polyesters backbone by Huisgen's 1,3-dipolar cycloaddition. This original combination of "clip" and "click" reactions provides a versatile and straightforward pathway for the synthesis of functional amphiphilic and degradable copolymers valuable for biomedical applications such as in drug-delivery.

  7. Roles of reactive chlorine species in trimethoprim degradation in the UV/chlorine process: Kinetics and transformation pathways.

    Science.gov (United States)

    Wu, Zihao; Fang, Jingyun; Xiang, Yingying; Shang, Chii; Li, Xuchun; Meng, Fangang; Yang, Xin

    2016-11-01

    The UV/chlorine process, which forms several reactive species including hydroxyl radicals (HO) and reactive chlorine species (RCS) to degrade contaminants, is being considered to be an advanced oxidation process. This study investigated the kinetics and mechanism of the degradation of trimethoprim (TMP) by the UV/chlorine process. The degradation of TMP was much faster by UV/chlorine compared to UV/H2O2. The degradation followed pseudo first-order kinetics, and the rate constant (k') increased linearly as the chlorine dosage increased from 20 μM to 200 μM and decreased as pH rose from 6.1 to 8.8. k' was not affected by chloride and bicarbonate but decreased by 50% in the presence of 1-mg/L NOM. The contribution of RCS, including Cl, Cl2(-) and ClO, to the degradation removal rate was much higher than that of HO and increased from 67% to 87% with increasing pH from 6.1 to 8.8 under the experimental condition. The increasing contribution of RCS to the degradation with increasing pH was attributable to the increase in the ClO concentration. Kinetic modeling and radical scavenging tests verified that ClO mainly attacked the trimethoxybenzyl moiety of TMP. RCS reacted with TMP much faster than HOCl/OCl(-) to form chlorinated products (i.e., m/z 325) and chlorinated disinfection byproducts such as chloroform, chloral hydrate, dichloroacetonitrile and trichloronitromethane. The hydroxylation and demethylation of m/z 325 driven by HO generated m/z 327 and m/z 341. Meanwhile, reactions of m/z 325 with HO and RCS/HOCl/OCl(-) generated dichlorinated and hydroxylated products (i.e., m/z 377). All the chlorinated products could be further depleted to produce products with less degree of halogenation in the UV/chlorine process, compared to dark chlorination. The acute toxicity to Vibrio fischeri by UV/chlorine was lower than chlorination at the same removal rate of TMP. This study demonstrated the importance of RCS, in particular, ClO, in the degradation of micropollutants

  8. Characterization of Chlorinated Ethene Degradation in a Vertical Flow Constructed Wetland

    Science.gov (United States)

    2007-03-01

    pathway for chlorinated volatiles in phytoremediation applications. Although transpiration of chlorinated solvents has been confirmed in studies ... case study publications and conference presentations providing support for the use of constructed wetlands for the treatment of chlorinated solvent...groundwater. This study characterized and evaluated the concentration of chlorinated ethenes within a vertical flow constructed wetland, fed with PCE

  9. Safety of water treatment by chlorine dioxide oxidation of aromatic hydrocarbons commonly found in water

    Energy Technology Data Exchange (ETDEWEB)

    Taymaz, K.; Williams, D.T.; Benoit, F.M.

    1979-01-01

    The safety of water treatment by chlorine dioxide oxidation of aromatic hydrocarbons commonly found in water and industrial wastewaters in the US was studied by observing the reactions of naphthalene and methylnaphthalenes in essentially chlorine-free, aqueous chlorine dioxide solutions. Naphthalene and methylnaphthalenes yielded chlorinated derivatives and oxidation products. Further research is recommended.

  10. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems.

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

    CERN Document Server

    Yang, Xuejuan; Glaser, Rainer; Zhong, Jianxin

    2016-01-01

    The so-called unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micrometer are ubiquitously seen in a wide variety of astrophysical regions. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, e.g., polycyclic aromatic hydrocarbon (PAH) molecules. The 3.3 micrometer aromatic C--H stretching feature is often accompanied by a weaker feature at 3.4 micrometer. The latter is often thought to result from the C--H stretch of aliphatic groups attached to the aromatic systems. The ratio of the observed intensity of the 3.3 micrometer aromatic C--H feature to that of the 3.4 micrometer aliphatic C--H feature allows one to estimate the aliphatic fraction of the UIE carriers, provided that the intrinsic oscillator strengths of the 3.3 micrometer aromatic C--H stretch (A3.3) and the 3.4 micrometer aliphatic C--H stretch (A3.4) are known. While previous studies on the aliphatic fraction of the UIE carriers were mostly based on the A3.4...

  12. Graphs: Associated Markov Chains

    OpenAIRE

    2012-01-01

    In this research paper, weighted / unweighted, directed / undirected graphs are associated with interesting Discrete Time Markov Chains (DTMCs) as well as Continuous Time Markov Chains (CTMCs). The equilibrium / transient behaviour of such Markov chains is studied. Also entropy dynamics (Shannon entropy) of certain structured Markov chains is investigated. Finally certain structured graphs and the associated Markov chains are studied.

  13. Effects of continuous chlorination on entrained estuarine plankton

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, S.J.; Foulk, H.R.

    1980-01-01

    Technical report: The effects of continuous chlorination in running sea water on entrained plankton were examined. The concentration of ATP was used as an indicator of biomass because: it is present in all living cells; the concentration is proportional to the living biomass; and dead cells lose ATP rapidly. Effects were measured by bioluminescence; luciferin-luciferase reagents from firefly lanterns were used to analyze ATP concentration. Results indicate that ATP measurement is an accurate, effective means of evaluating damage done to planktonic organisms by continuous chlorination. Further studies of the effects of low-concentration, continuous chlorination are recommended. (13 references, 1 table)

  14. Chlorine Dioxide Gas Treatment of Cantaloupe and Residue Analysis

    OpenAIRE

    Kaur, Simran

    2013-01-01

    Chlorine dioxide is a selective oxidant and powerful antimicrobial agent. Previous work has shown that treatment of cantaloupe with chlorine dioxide gas at 5 mg/L for 10 minutes results in a 4.6 and 4.3 log reduction of E. coli O157:H7 and L. monocytogenes respectively. A significant reduction (p Current analytical methods for chlorine dioxide and chloroxyanions are only applicable to aqueous samples. Some of these methods have been used to determine surface residues in treated products by...

  15. Selective determination of chlorine dioxide using gas diffusion flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hollowell, D.A.; Pacey, G.E.; Gordon, G.

    1985-12-01

    An automated absorbance technique for the determination of aqueous chlorine dioxide has been developed by utilizing gas diffusion flow injection analysis. A gas diffusion membrane is used to separate the donor (sampling) stream from the acceptor (detecting) stream. The absorbance of chlorine dioxide is monitored at 359 nm. The first method uses distilled water as the acceptor stream and gives a detection limit of 0.25 mg/L chlorine dioxide. This system is over 550 times more selective for chlorine dioxide than chlorine. To further minimize chlorine interference, oxalic acid is used in the acceptor stream. The detection limit for this system is 0.45 mg/L chlorine dioxide. This second system is over 5400 times more selective for chlorine dioxide than chlorine. Both methods show excellent selectivity for chlorine dioxide over iron and manganese compounds, as well as other oxychlorinated compounds such as chlorite and perchlorate ions. 18 references, 7 figures, 3 tables.

  16. RESEARCH ON MATHEMATICAL SIMULATION OF RESIDUAL CHLORINE DECAY AND OPTIMIZATION OF CHLORINATION ALLOCATION OF URBAN WATER DISTRIBUTION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    TIAN Yi-mei; CHI Hai-yan; LI Hong; SHAN Jin-lin; ZHAI Chun-nian

    2005-01-01

    The concentration of Residual Chlorine (RC) frequently violates the standard in situations of urban water distribution system with large water supply area and long time of distribution.If chlorine dosage increases within water treatment plant, although RC in distribution system could meet water quality standard, Disinfection By-Products (DBPs) such as hydrocarbon halide rises.In the paper, a mathematical model of chlorine allocation optimization was presented based on reaction kinetics mechanism and optimization theory to solve the problem.The model includes the objective function of minimizing annual operation cost and constraints of RC standard and rational chlorination station distribution, and solving by 0-1 Integer Programming (IP).The model had been applied to a real water distribution system.The simulation results of the model showed that adding chlorine in water distribution system remarkably improved water quality and reduced the operation cost by 49.3% per year less than chlorine dosed only in water treatment plant to meet RC standard.The results prove adding chlorine in water distribution system based on the model can bring both technological and economic advancement.

  17. Distribution and sources of aliphatic hydrocarbons and fatty acids in surface sediments of a tropical estuary south west coast of India (Cochin estuary).

    Science.gov (United States)

    Gireeshkumar, T R; Deepulal, P M; Chandramohanakumar, N

    2015-03-01

    Surface sediments samples from the Cochin estuary were measured for elemental, stable isotopic and molecular biomarkers (aliphatic hydrocarbons and fatty acids) to study the sources and distribution of sedimentary organic matter. Concentrations of total organic carbon (TOC), total nitrogen (TN) and stable isotopic ratios of carbon (δ(13)C) ranged from 0.62 to 2.74 %, 0.09 to 0.25 % and -27.5 to 21.7 ‰, respectively. Sedimentary n-alkanes ranged from 6.03 to 43.23 μg g(-1) with an average of 16.79 μg g(-1), while total fatty acids varied from 22.55 to 440.69 μg g(-1). The TOC/TN ratios and δ(13)C suggest a mixture of marine- and terrestrial-derived organic matter in the surface sediments with increasing contributions from marine-derived organic matter towards the seaward side. Long-chain n-alkanes derived from higher plants predominated the inner part of the estuary, while short-chain n-alkanes derived from planktonic sources predominated the bar mouth region. The even carbon preference of the C12-C22 n-alkanes may refer to the direct biogenic contribution from bacteria, fungi and yeast species and to the potential direct petroleum inputs. The presence of odd mid-chain n-alkanes in the sediments indicates the organic matter inputs from submerged and floating macrophytes (water hyacinth). Various molecular indices such as carbon preference index, terrestrial to aquatic ratio, average chain length and the ratios of mid-chain n-alkanes support the aforementioned inferences. The high contribution of odd and branched chain fatty acids along with very low contribution of polyunsaturated fatty acids, suggest the effective utilisation of algae-derived organic matter by bacteria and the effective recycling of labile organic matter in whole settling and deposition processes. The distributional variability of n-alkanes and fatty acids reveals the preferential utilisation of marine-derived organic matter and the selective preservation of terrestrial

  18. Effect of electron beam irradiation on the biodegradability of aromatic aliphatic copolyester film and their blend with corn starch

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Leonardo G. Andrade e; Poveda, Patricia N.S., E-mail: lgasilva@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rezende, Maira L.; Rosa, Derval S. [Universidade Sao Francisco, Itatiba, SP (Brazil)

    2009-07-01

    Biodegradable and green plastics have been studied in the last years. The aim of this paper is to study the effect of electron beam irradiation on the biodegradability of aromatic aliphatic copolyester film and their blend with corn starch. The samples were irradiated at different doses 10 and 40 kGy in a linear accelerator. The biodegradability of the materials was evaluated by two methods: soil simulated and enzymatic. In the method enzymatic when it was used alpha-amylase, the irradiated samples presented faster biodegradation than the references non irradiated. The blend of aromatic aliphatic copolyester with corn starch (Ecobras{sup R}) irradiated presented a bigger biodegradability than the aromatic aliphatic copolyester (Ecoflex{sup R}) film in both methods studied. (author)

  19. Drude polarizable force field for aliphatic ketones and aldehydes, and their associated acyclic carbohydrates

    Science.gov (United States)

    Small, Meagan C.; Aytenfisu, Asaminew H.; Lin, Fang-Yu; He, Xibing; MacKerell, Alexander D.

    2017-02-01

    The majority of computer simulations exploring biomolecular function employ Class I additive force fields (FF), which do not treat polarization explicitly. Accordingly, much effort has been made into developing models that go beyond the additive approximation. Development and optimization of the Drude polarizable FF has yielded parameters for selected lipids, proteins, DNA and a limited number of carbohydrates. The work presented here details parametrization of aliphatic aldehydes and ketones (viz. acetaldehyde, propionaldehyde, butaryaldehyde, isobutaryaldehyde, acetone, and butanone) as well as their associated acyclic sugars (uc(d)-allose and uc(d)-psicose). LJ parameters are optimized targeting experimental heats of vaporization and molecular volumes, while the electrostatic parameters are optimized targeting QM water interactions, dipole moments, and molecular polarizabilities. Bonded parameters are targeted to both QM and crystal survey values, with the models for ketones and aldehydes shown to be in good agreement with QM and experimental target data. The reported heats of vaporization and molecular volumes represent a compromise between the studied model compounds. Simulations of the model compounds show an increase in the magnitude and the fluctuations of the dipole moments in moving from gas phase to condensed phases, which is a phenomenon that the additive FF is intrinsically unable to reproduce. The result is a polarizable model for aliphatic ketones and aldehydes including the acyclic sugars uc(d)-allose and uc(d)-psicose, thereby extending the available biomolecules in the Drude polarizable FF.

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

    Science.gov (United States)

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

    2017-02-01

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

  1. Branched aliphatic alkanes of shell bar section in Qarhan Lake, Qaidam Basin and their paleoclimate significance

    Institute of Scientific and Technical Information of China (English)

    ZHANG HuCai; CHANG FengQin; LI Bin; LEI GuoLiang; CHEN Yue; ZHANG WenXiang; NIU Jie; FAN HongFang; YANG MingSheng

    2007-01-01

    Biomarkers of paleolake deposits from Qarhan Salt Lake in Qaidam Basin, northwest China were systematically analyzed and the A-C series compounds of branched aliphatic alkanes with quaternary substituted carbon atom (BAQCs) were identified. The homologous distinguished three series, A-C,were identified as 5,5-diethylalkanes, 6,6-diethylalkanes and 5-butyl, 5-ethylalkanes series, and their relative abundance was A > B > C. Series A and C were characterized by odd carbon numbers, whereas series B was characterized by even carbon numbers. The high values of series A corresponded with the high values of series B and C. Therefore, it can be concluded that series A, B and C possess a similar biological origin. The abundance of series A was relatively Iow in the lower part of the section compared with that in the upper part, implying that these series originated from bacteria and/or algae more prevalent in fresh-mesohaline water, and such kinds of bacteria and/or algae are most likely to be thermophilous species. The A25/nC25 ratio differences in the section show that such branched aliphatic alkanes can be treated as one kind of environmental change proxy for paleolake evolution and may provide important information for the climate reconstruction of the Late Pleistocene.

  2. Drude polarizable force field for aliphatic ketones and aldehydes, and their associated acyclic carbohydrates.

    Science.gov (United States)

    Small, Meagan C; Aytenfisu, Asaminew H; Lin, Fang-Yu; He, Xibing; MacKerell, Alexander D

    2017-02-11

    The majority of computer simulations exploring biomolecular function employ Class I additive force fields (FF), which do not treat polarization explicitly. Accordingly, much effort has been made into developing models that go beyond the additive approximation. Development and optimization of the Drude polarizable FF has yielded parameters for selected lipids, proteins, DNA and a limited number of carbohydrates. The work presented here details parametrization of aliphatic aldehydes and ketones (viz. acetaldehyde, propionaldehyde, butaryaldehyde, isobutaryaldehyde, acetone, and butanone) as well as their associated acyclic sugars (D-allose and D-psicose). LJ parameters are optimized targeting experimental heats of vaporization and molecular volumes, while the electrostatic parameters are optimized targeting QM water interactions, dipole moments, and molecular polarizabilities. Bonded parameters are targeted to both QM and crystal survey values, with the models for ketones and aldehydes shown to be in good agreement with QM and experimental target data. The reported heats of vaporization and molecular volumes represent a compromise between the studied model compounds. Simulations of the model compounds show an increase in the magnitude and the fluctuations of the dipole moments in moving from gas phase to condensed phases, which is a phenomenon that the additive FF is intrinsically unable to reproduce. The result is a polarizable model for aliphatic ketones and aldehydes including the acyclic sugars D-allose and D-psicose, thereby extending the available biomolecules in the Drude polarizable FF.

  3. Correlation between NQR parameters and residue size of aliphatic amino acids and their dimers.

    Science.gov (United States)

    Ghaderi, Ali Reza; Sabzyan, Hassan; Hadipour, Nasser L

    2006-03-01

    Nuclear quadrupole coupling constants (NQCC), chi, and asymmetry parameters, eta, of 2D, 14N and 17O nuclei have been calculated for aliphatic amino acids and their dimers using MP2/6-311++G** method to shed some light on the differences between the structural parameters in the aliphatic amino acids and their dimers. For this purpose, electric field gradient (EFG) at the sites of quadrupolar nuclei have been calculated and evaluated for each compound. A correlation is observed between the calculated NQCC parameters and the conformational structures of the compounds, showing that extraction of structural data from the NQR spectra might be promising. Our results showed that 17O NQCC of terminal carboxylic acid and 14N NQCC of the terminal amino groups are, respectively, the least and the most sensitive parameters to the variation of the size of the residue. It is found also that conformation of R (i.e. values of the dihedral angles) plays a very effective role in the determination of the values of the calculated NQCC parameters. Sensitivity of the NQR parameters to the changes in the conformational structure is significantly greater (nearly 20-fold) than that to the changes in the other structural parameters such as bond lengths.

  4. Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

  5. [Cloning and analysis of a new aliphatic amidase gene from Rhodococcus erythropolis TA37].

    Science.gov (United States)

    Lavrov, K V; Karpova, I Yu; Epremyan, A S; Yanenko, A S

    2014-10-01

    A new aliphatic amidase gene (ami), having a level of similarity with the nearest homologs of no more than 77%, was identified in the Rhodococcus erythropolis TA37 strain, which is able to hydrolyze a wide range of amides. The amidase gene was cloned within a 3.7 kb chromosomal locus, which also contains putative acetyl-CoA ligase and ABC-type transportergenes. The structure of this locus in the R. erythropolis TA37 strain differs from the structure of loci in other Rhodococcus strains. The amidase gene is expressed in Escherichia coli cells. It was demonstrated that amidase (generated in the recombinant strain) efficiently hydrolyzes acetamide (aliphatic anmide) and does not use 4'-nitroacetanilide (N-substituted amide) as a substrate. Insertional inactivation of the amidase gene in the R. erythropolis TA37 strain results in a considerable decrease (by at least 6-7 times) in basal amidase activity, indicating functional amidase activity in the R. erythropolis TA37 strain.

  6. Aliphatic amidase of Rhodococcus rhodochrous PA-34: Purification, characterization and application in synthesis of acrylic acid.

    Science.gov (United States)

    Thakur, Neerja; Kumar, Vijay; Sharma, Nirmal Kant; Thakur, Shikha; Bhalla, Tek Chand

    2016-01-01

    An intracellular aliphatic amide degrading inducible amidase produced by Rhodococcus rhodochrous PA-34 was characterized and acrylic acid synthesis from acrylamide was carried out using whole cell amidase. A bioprocess was developed at 50 ml fed batch reaction using 400 mM acrylamide feeding at an interval of 30 min resulted in the production of 4 g acrylic acid with volumetric and catalytic productivity of 80 g/l and 19 g/g/h respectively. The amidase of this organism had molecular weight of 40 kDa and was purified to 8.5 fold with 8% yield. This enzyme was active within the temperature range of 30 to 60 °C, with optimum temperature 45 °C and pH 7.5. The Vmax, Km, and kcat of purified amidase were calculated as 250 U/mg protein, 4.5 mM, and 166 sec-1 for acrylamide. The enzyme showed tolerance to metal chelating agent (EDTA) and was strongly inhibited by heavy metal ions Hg2+, Ag2+, Cu2+ and Co2+. R. rhodochrous PA-34 amidase preferentially hydrolyzed small aliphatic toxic amide such as acrylamide. Thus, the amidase of R. rhodochrous PA-34 is promising biocatalyst for the synthesis of industrially important acids and biodegradation of toxic amides.

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

    Science.gov (United States)

    Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2012-04-01

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

  8. Aliphatic carboxylic acids and alcohols as efficiency and elution strength enhancers in micellar liquid chromatography.

    Science.gov (United States)

    Boichenko, Alexander P; Berthod, Alain

    2010-09-03

    Micellar liquid chromatography (MLC) uses surfactant solutions as mobile phases with added organic additives to enhance both the elution strength and the chromatographic efficiency. Two aliphatic carboxylic acids (1-butanoic and 1-pentanoic) were used as MLC additives and compared with the two corresponding alcohols (1-butanol, 1-pentanol) in terms of elution strength, efficiency and selectivity. A set of 11 phenol derivatives was used as probe compounds. All micellar mobile phases were prepared with sodium dodecylsulfate (SDS) with concentration ranging from 0.05 to 0.15M and the modifier content within 1.0 and 5.0% (v/v). The elution strength of different mobile phases containing a constant amount of SDS and different amounts of modifiers; and mobile phases containing a constant amount of modifier and different SDS concentration were determined and discussed. The effect of the acid modifiers on efficiency was studied constructing van Deemter plots that showed no minimum within the 0.01-0.7mL/min flow rate range studied. Temperature effects were also studied constructing the classical van't Hoff plots. The slight curvature of the plots in the 25-70 degrees C range may indicate some modification of the surfactant-bonded moiety layer on the stationary phase surface. Since no definitive advantage of the use of aliphatic acids were established compared to their alcohol counterpart, their terrible smell will probably preclude their use as MLC organic modifiers.

  9. Aliphatic and aromatic hydrocarbons in particulate fallout of Alexandria, Egypt: Sources and implications

    Energy Technology Data Exchange (ETDEWEB)

    Aboul-Kassim, T.A.T.; Simoneit, B.R.T. [Oregon State Univ., Corvallis, OR (United States)

    1995-10-01

    Particulate fallout samples (PFS) were collected in Alexandria, and their aliphatic and aromatic hydrocarbon compositions were determined both quantitatively and qualitatively to characterize the homologous and biomarker compounds in terms of their original sources. The results show that all samples contain aliphatic hydrocarbons, including n-alkanes, UCM, isoprenoids, tri- and tetracyclic terpanes, hopanes, and steranes/diasteranes. The main source of these compounds is from petrochemical contamination with trace input of terrestrial higher plant wax. In addition, polycyclic aromatic hydrocarbons, which are considered to be combustion products from fossil fuels such as petroleum, are also widely distributed in all samples. Multivariate statistical analysis, including extended Q-mode factor analysis and linear programming technique, was performed in order to reduce the hydrocarbon data set into a meaningful number of end members (sources). This analysis indicates that there are two significant end members explaining 90% of the total variation among the samples and confirming petrochemical (79.6%), and thermogenic/pyrolytic (10.4%) sources in the PFS model. 65 refs., 7 figs., 4 tabs.

  10. Occurrence and human exposure of parabens and their chlorinated derivatives in swimming pools.

    Science.gov (United States)

    Li, Wenhui; Shi, Yali; Gao, Lihong; Liu, Jiemin; Cai, Yaqi

    2015-11-01

    As an emerging group of endocrine-disrupting chemicals, parabens have attracted growing attention due to their potential effects on human health. In the present study, the occurrence and distribution of eight parabens, four chlorinated parabens, and their common hydrolysis product, p-hydroxybenzoic acid (PHBA), were investigated in 39 swimming pools in Beijing, China. Methyl paraben and propyl paraben were the predominant compounds in swimming pools, accounting for 91.2 % of the total parabens. It is noteworthy that octyl paraben, a paraben with longer chain, was firstly detected in this study. There were several factors affecting the levels of parabens among the 39 swimming pools. The concentrations of parabens and chlorinated derivatives detected in indoor pools (144 ng L(-1)) were roughly 20-fold higher than those in outdoor pools (6.78 ng L(-1)). Hotel pools appear to present higher level of target compounds (361 ng L(-1)) than that in health club (228 ng L(-1)), municipal (130 ng L(-1)), school (75.6 ng L(-1)), and community pools (63.0 ng L(-1)). Moreover, the level of these compounds in pools during weekends (174 ng L(-1)) was much higher than that during weekdays (52.3 ng L(-1)). The dynamics of target compounds were also investigated to provide a general trend of the level of parabens in a school indoor swimming pool during a 14-week period. Human exposure assessment was conducted to estimate the potential risk of exposure to parabens and their chlorinated derivatives in swimming pools. Considering the total exposure dose of multiple parabens, human exposure to parabens from the water of swimming pools is negligible. However, the threat of these parabens to children in swimming pool should be concerned.

  11. Complete Non-Radioactive Operability Tests for Cladding Hull Chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Emory D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Jared A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hylton, Tom D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brunson, Ronald Ray [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunt, Rodney Dale [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); DelCul, Guillermo Daniel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bradley, Eric Craig [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-01

    Non-radioactive operability tests were made to test the metal chlorination reactor and condenser and their accessories using batch chlorinations of non-radioactive cladding samples and to identify optimum operating practices and components that need further modifications prior to installation of the equipment into the hot cell for tests on actual used nuclear fuel (UNF) cladding. The operability tests included (1) modifications to provide the desired heating and reactor temperature profile; and (2) three batch chlorination tests using, respectively, 100, 250, and 500 g of cladding. During the batch chlorinations, metal corrosion of the equipment was assessed, pressurization of the gas inlet was examined and the best method for maintaining solid salt product transfer through the condenser was determined. Also, additional accessing equipment for collection of residual ash and positioning of the unit within the hot cell were identified, designed, and are being fabricated.

  12. Modeling of residual chlorine in water distribution system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Water quality within water distribution system may vary with both location and time. Water quality models are used to predict the spatial and temporal variation of water quality throughout water system. A model of residual chlorine decay in water pipe has been developed,given the consumption of chlorine in reactions with chemicals in bulk water, bio-films on pipe wall, in corrosion process, and the mass transport of chlorine from bulk water to pipe wall. Analytical methods of the flow path from water sources to the observed point and the water age of every observed node were proposed. Model is used to predict the decay of residual chlorine in an actual distribution system. Good agreement between calculated and measured values was obtained.

  13. Characters of chlorine isotopic composition in ocean water

    Digital Repository Service at National Institute of Oceanography (India)

    Xiao, Y.; Zhou, Y.; Liu, W.G.; Hong, A.; Wang, Q.; Wang, Y.; Wei, H.; Shirodkar, P.V.

    The chlorine isotopic composition of ocean water was determined using thermal ionization mass spectrometry based on the measurement of Cs sub(2) Cl sup(+) ion. The results show that the sup(37) Cl/ sup(35) Cl ratios are basically homogeneous...

  14. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfection byproducts (DBPs) at a pilot plant in Evansville, IN, which uses chlorine dioxide as a primary disinfectant. Unconventional multispectral identification techniques (gas chromatography combined with high- and low reso...

  15. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfectant byproducts (DNPS) at a pilot plant in Evansville, IN, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high- and low-resolu...

  16. Kinetics of Chlorine Decay in Water Distribution Systems

    Institute of Scientific and Technical Information of China (English)

    周建华; 薛罡; 赵洪宾; 汪永辉; 郭美芳

    2004-01-01

    A combined first and second-order model, which includes bulk decay and wall decay, was developed to describe chlorine decay in water distribution systems. In the model the bulk decay has complex relationships with total organic carbon (TOC), the initial chlorine concentration and the temperature. Except for the initial stages they can be simplified into a linear increase with TOC, a linear decrease with initial chlorine concentration and an exponential relationship with the temperature. The model also explains why chlorine decays rapidly in the initial stages. The parameters of model are determined by deriving the best fitness with experimental data. And the accuracy of model has been verified by using the experimental data and the monitoring data in a distribution system.

  17. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquife

  18. CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

    Science.gov (United States)

    This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

  19. Fate of free chlorine in drinking water during distribution in premise plumbing.

    Science.gov (United States)

    Zheng, Muzi; He, Chunguang; He, Qiang

    2015-12-01

    Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of pipe deposits. In contrast, the impact on chlorine decay by pipe deposits was not significant in galvanized iron and PVC pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise plumbing.

  20. Silver-Catalyzed C(sp(3))-H Chlorination.

    Science.gov (United States)

    Ozawa, Jun; Kanai, Motomu

    2017-03-17

    A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp(3))-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.

  1. Bromoform production in tropical open-ocean waters: OTEC chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, E.O.; Valentine, R.

    1981-09-01

    The bromoform, and other volatile organics produced while chlorinating both the evaporator and condenser seawater during operation of the one megawatt (1 MW) OTEC-1 test facility are reported. Although many halogenated compounds might be produced as a result of chlorination, the quantitative analyses in this study focused on volatile EPA priority pollutants. Bromoform is the compound specifically recognized as a potential pollutant. Its concentration may be indicative of other halogenated species.

  2. Assessment of the risk of transporting liquid chlorine by rail

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, W.B.

    1980-03-01

    This report presents the risk of shipping liquid chlorine by rail. While chlorine is not an energy material, there are several benefits to studying chlorine transportation risks. First, chlorine, like energy materials, is widely used as a feedstock to industry. Second, it is the major purification agent in municipal water treatment systems and therefore, provides direct benefits to the public. Finally, other risk assessments have been completed for liquid chlorine shipments in the US and Europe, which provide a basis for comparison with this study. None of the previous PNL energy material risk assessments have had other studies for comparison. For these reasons, it was felt that a risk assessment of chlorine transportation by rail could provide information on chlorine risk levels, identify ways to reduce these risks and use previous studies on chlorine risks to assess the strengths and weaknesses of the PNL risk assessment methodology. The risk assessment methodology used in this study is summarized. The methodology is presented in the form of a risk assessment model which is constructed for ease of periodic updating of the data base so that the risk may be reevaluated as additional data become available. The report is sectioned to correspond to specific analysis steps identified in the model. The transport system and accident environment are described. The response of the transport system to accident environments is described. Release sequences are postulated and evaluated to determine both the likelihood and possible consequences of a release. Supportive data and analyses are given in the appendices. The risk assessment results are related to the year 1985 to allow a direct comparison with other reports in this series.

  3. SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; Brian02 Looney, B; Michael J. Truex; Charles J. Newell

    2006-08-16

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  4. Identification and Synthesis of (Z,Z-8,11-Heptadecadienyl Formate and (Z-8-Heptadecenyl Formate: Unsaturated Aliphatic Formates Found in the Unidentified Astigmatid Mite, Sancassania sp. Sasagawa (Acari: Acaridae

    Directory of Open Access Journals (Sweden)

    Nobuhiro Shimizu

    2016-05-01

    Full Text Available We identified two aliphatic formates, (Z,Z-8,11-heptadecadienyl formate and (Z-8-heptadecenyl formate in the opisthonotal gland secretions of an unidentified acarid species, namely Sancassania sp. Sasagawa. Both compounds were isolated using silica gel column chromatography and the structures were elucidated by 1H-NMR and GC/FT-IR. Further information on the double bond positions was obtained by GC-MS analysis of the corresponding dimethyl disulfide derivatives. Based on the estimated structures of the two formates and using linoleic and oleic acids as the respective starting materials, a simple four-step synthesis was achieved via Barton decarboxylation as the key step. The aliphatic formates identified in acarids thus far are neryl formate ((Z-3,7-dimethylocta-2,6-dienyl formate and lardolure (1,3,5,7-tetramethyldecyl formate, and both have been reported to have pheromone functions. The biological function of the two formates isolated in this study is currently being investigated. Although we can speculate that the two compounds were biosynthesized from linoleic and oleic acid, there is a possibility that the synthetic processes featured a novel chain shortening and formic acid esterification mechanism.

  5. Identification and Synthesis of (Z,Z)-8,11-Heptadecadienyl Formate and (Z)-8-Heptadecenyl Formate: Unsaturated Aliphatic Formates Found in the Unidentified Astigmatid Mite, Sancassania sp. Sasagawa (Acari: Acaridae).

    Science.gov (United States)

    Shimizu, Nobuhiro; Sakata, Daisuke; Miyazaki, Honami; Shimura, Yasuhiro; Kuwahara, Yasumasa

    2016-05-11

    We identified two aliphatic formates, (Z,Z)-8,11-heptadecadienyl formate and (Z)-8-heptadecenyl formate in the opisthonotal gland secretions of an unidentified acarid species, namely Sancassania sp. Sasagawa. Both compounds were isolated using silica gel column chromatography and the structures were elucidated by ¹H-NMR and GC/FT-IR. Further information on the double bond positions was obtained by GC-MS analysis of the corresponding dimethyl disulfide derivatives. Based on the estimated structures of the two formates and using linoleic and oleic acids as the respective starting materials, a simple four-step synthesis was achieved via Barton decarboxylation as the key step. The aliphatic formates identified in acarids thus far are neryl formate ((Z)-3,7-dimethylocta-2,6-dienyl formate) and lardolure (1,3,5,7-tetramethyldecyl formate), and both have been reported to have pheromone functions. The biological function of the two formates isolated in this study is currently being investigated. Although we can speculate that the two compounds were biosynthesized from linoleic and oleic acid, there is a possibility that the synthetic processes featured a novel chain shortening and formic acid esterification mechanism.

  6. Shock-tube pyrolysis of chlorinated hydrocarbons - Formation of soot

    Science.gov (United States)

    Frenklach, M.; Hsu, J. P.; Miller, D. L.; Matula, R. A.

    1986-01-01

    Soot formation in pyrolysis of chlorinated methanes, their mixtures with methane, and chlorinated ethylenes were studied behind reflected shock waves by monitoring the attenuation of an He-Ne laser beam. An additional single-pulse shock-tube study was conducted for the pyrolysis of methane, methyl chloride, and dichloromethane. The experiments were performed at temperatures 1300-3000 K, pressures of 0.4-3.6 bar, and total carbon atom concentrations of 1-5 x 10 to the 17th atoms cu cm. The amounts of soot produced in the pyrolysis of chlorinated hydrocarbons are larger than that of their nonchlorinated counterparts. The sooting behavior and product distribution can be generally explained in terms of chlorine-catalyzed chemical reaction mechanisms. The pathway to soot from chlorinated methanes and ethylenes with high H:Cl ratio proceeds via the formation of C2H, C2H2, and C2H3 species. For chlorinated hydrocarbons with low H:Cl ratio, the formation of C2 and its contribution to soot formation at high temperatures becomes significant. There is evidence for the importance of CHCl radical and its reactions in the pyrolysis of dichloromethane.

  7. Prompt gamma analysis of chlorine in concrete for corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2006-02-15

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine {gamma}-rays and calcium {gamma}-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine {gamma}-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  8. Prompt gamma analysis of chlorine in concrete for corrosion study.

    Science.gov (United States)

    Naqvi, A A; Nagadi, M M; Al-Amoudi, O S B

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  9. Chlorine dioxide project allows Stora to clean up, use hardwoods

    Energy Technology Data Exchange (ETDEWEB)

    Butters, G.

    1988-10-01

    Effluent fouling into the Strait of Canso between Nova Scotia mainland and Cape Breton Island has caused Stora Forest Industries Ltd. to develop a $5.6 million solution to its chlorine and acid problems. In 1987, Stora produced about 160,000 tonnes of market pulp where their resource base increasingly consisted of hardwood. The company uses hardwood chips for a growing percentage of its annual pulp production and for its hog fuel boiler, but became faced with having to use more local hardwoods which contributes to the resin problem. Their solution was to construct a 12-tpd chlorine dioxide generator, a process using dry sodium chlorate added to concentrated H/sub 2/SO/sub 4/, The products are chlorine dioxide and highly concentrated sulphuric acid resulting from the elimination of water at the starting point. This will eliminate the acid effluent from the generator and the sulphuric acid will be recycled to the top of the chlorine dioxide generation process. In the new process, ClCO/sub 2/ replaces 70% of the chlorine in the first stage, with 100% substitution a goal. In addition to eliminating the chlorine, other benefits include an increase in pulp production, a nominal increase in pulp strength, lower production costs, and an economic incentive to harvest the area's mixed-wood stands.

  10. Zebra mussel control using periodic chlorine dioxide treatments

    Energy Technology Data Exchange (ETDEWEB)

    Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Coyle, J. [Central Illinois Public Service, Merdosia, IL (United States); Crone, D. [Illinois Power Company, Alton, IL (United States)] [and others

    1996-08-01

    This paper summarizes the EPRI report (TR-105202) on the same topic as well as presents changes in current thinking on the suitability (applicability) of chlorine dioxide for fouling control. Chlorine dioxide was tested as a zebra mussel biocide at two steam electric generating stations in Illinois and one in Indiana. The purpose of these studies was to determine the efficacy of chlorine dioxide in killing zebra mussels and to develop site specific treatment programs for the three utilities. The Electric Power Research Institute (EPRI) Zebra Mussel Consortium sponsored the testing of this recent use of chlorine dioxide. The raw water system at Central Illinois Public Service`s Meredosia Station, on the Illinois River, received applications of chlorine dioxide in April, July, and September 1994. The raw water system at Illinois Power Company`s Wood River Station, on the Mississippi River, received applications in July 1993, January, April, May, July, and September 1994. The Gallagher Station, on the Ohio River, was treated in July and October 1994. Chlorine dioxide was generated on-site and injected into the water intake structure. Both cooling and service water systems were treated at the facilities. 6 refs., 13 figs.

  11. Chlorobenzene outputs from combustion of chlorinated organic and inorganic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Green, A.E.S.; Vitali, J.A.; Miller, T.L. [Univ. of Florida, Gainesville, FL (United States)

    1994-12-31

    The authors consider the gas phase formation of chlorinated benzenes and phenols as precursors of chlorinated dioxins and furans from the combustion of solid fuels containing organically bound chlorine. The model investigated is intended to apply to the combustion of medical waste, municipal waste and coals containing chlorine. Assuming a temperature-time profile drawn from incinerator experiments, the authors use kinetic modeling with known reaction rates to further investigate four models of chlorinated benzene formation. Since reaction rates for most chlorination processes are now known, the authors choose simple systems of reaction rates that yield outputs that can be made approximately compatible with results of the Pittsfield-Vicon incinerator and Clean Combustion Technology Laboratory experiments. The authors also consider recent measurements of HCI emissions from crematoria and the implication of this work with respect to the benefits of material substitution in medical and municipal waste incineration. These benefits should also accompany the dechlorination of coals. The authors note the disparity between the prevailing USA position and the emerging position of Germany on the issue of halogenated plastics. The authors also note that Europe and Asia are beginning to address solid fuel issues as a consolidated discipline. This pattern should be helpful in broadening the understanding of solid fuels combustion processes and in ferreting out erroneous data and conclusions. This is important in view of the recent concern about the role of low dioxin exposure levels on fetal development and the immune system.

  12. Disinfection of swine wastewater using chlorine, ultraviolet light and ozone.

    Science.gov (United States)

    Macauley, John J; Qiang, Zhimin; Adams, Craig D; Surampalli, Rao; Mormile, Melanie R

    2006-06-01

    Veterinary antibiotics are widely used at concentrated animal feeding operations (CAFOs) to prevent disease and promote growth of livestock. However, the majority of antibiotics are excreted from animals in urine, feces, and manure. Consequently, the lagoons used to store these wastes can act as reservoirs of antibiotics and antibiotic-resistant bacteria. There is currently no regulation or control of these systems to prevent the spread of these bacteria and their genes for antibiotic resistance into other environments. This study was conducted to determine the disinfection potential of chlorine, ultraviolet light and ozone against swine lagoon bacteria. Results indicate that a chlorine dose of 30 mg/L could achieve a 2.2-3.4 log bacteria reduction in lagoon samples. However, increasing the dose of chlorine did not significantly enhance the disinfection activity due to the presence of chlorine-resistant bacteria. The chlorine resistant bacteria were identified to be closely related to Bacillus subtilis and Bacillus licheniformis. A significant percentage of lagoon bacteria were not susceptible to the four selected antibiotics: chlortetracycline, lincomycin, sulfamethazine and tetracycline (TET). However, the presence of both chlorine and TET could inactivate all bacteria in one lagoon sample. The disinfection potential of UV irradiation and ozone was also examined. Ultraviolet light was an effective bacterial disinfectant, but was unlikely to be economically viable due to its high energy requirements. At an ozone dose of 100 mg/L, the bacteria inactivation efficiency could reach 3.3-3.9 log.

  13. Purification of highly chlorinated dioxins degrading enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, K.; Furuichi, T.; Koike, K.; Kuboshima, M. [Hokkaido Univ. (Japan). Division of Environment Resource Engineering, Graduate School of Engineering

    2004-09-15

    Soil contamination caused by dioxins in and around sites of incinerators for municipal solid waste (MSW) is a concern in Japan. For example, scattering wastewater from a wet gas scrubber at an MSW incinerator facility in Nose, Osaka caused soil and surface water contamination. The concentration of dioxins in the soil was about 8,000 pg-TEQ/g. Other contamination sites include soils on which fly ash has been placed directly or improperly stored and landfill sites that have received bottom and fly ash over a long period. Some countermeasures are required immediately at these dioxins-contaminated sites. We have previously developed bioreactor systems for dioxin-contaminated water and soil. We have shown that a fungus, Pseudallescheria boydii (P. boydii), isolated from activated sludge treating wastewater that contained dioxins, has the ability to degrade highly chlorinated dioxins. A reaction product of octachlorinated dibenzo-p-dioxin (OCDD) was identified as heptachlorinated dibenzo-p-dioxin. Therefore, one of the pathways for degradation of OCDD by this fungus was predicted to be as follows: OCDD is transformed by dechlorination and then one of the remaining aromatic rings is oxidized. To apply P. boydii to on-site technologies (e.g., bioreactor systems), as well as in situ technologies, enzyme treatment using a dioxin-degrading enzyme from P. boydii needs to be developed because P. boydii is a weak pathogenic fungus, known to cause opportunistic infection. As a result, we have studied enzyme purification of nonchlorinated dioxin, namely, dibenzo-pdioxin (DD). However, we did not try to identify enzymes capable of degrading highly chlorinated dioxins. This study has elucidated a method of enzyme assay for measuring OCDD-degrading activity, and has attempted to purify OCDD-degrading enzymes from P. boydii using enzyme assay. In addition, as first step toward purifying 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-TCDD degradation tests were carried out

  14. Transition-metal-free visible-light photoredox catalysis at room-temperature for decarboxylative fluorination of aliphatic carboxylic acids by organic dyes.

    Science.gov (United States)

    Wu, Xinxin; Meng, Chunna; Yuan, Xiaoqian; Jia, Xiaotong; Qian, Xuhong; Ye, Jinxing

    2015-07-28

    We report herein an efficient, general and green method for decarboxylative fluorination of aliphatic carboxylic acids. By using a transition-metal-free, organocatalytic photoredox system, the reaction of various aliphatic carboxylic acids with the Selectfluor reagent afforded the corresponding alkyl fluorides in satisfactory yields under visible light irradiation at room temperature.

  15. Synergistic effect between UV and chlorine (UV/chlorine) on the degradation of carbamazepine: Influence factors and radical species.

    Science.gov (United States)

    Wang, Wen-Long; Wu, Qian-Yuan; Huang, Nan; Wang, Ting; Hu, Hong-Ying

    2016-07-01

    For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants (kobs,CBZ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl(-) and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min(-1) and that by Cl decreased from 0.40 to 0.11 min(-1). The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 10(10) M(-1) s(-1). Anions of HCO3(-) (1-50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl(-) did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14-0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione.

  16. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ren, Hongqiang, E-mail: hqren@nju.edu.cn; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L{sup −1}. The transformation kinetic data for ARGs removal (log C{sub 0} / C) followed the second-order reaction kinetic model with FC dosage (R{sup 2} = 0.6829–0.9999) and contact time (R{sup 2} = 0.7353–8634), respectively. Higher ammonia nitrogen (NH{sub 3}–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl{sub 2}:NH{sub 3}–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm{sup −2}, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - Highlights: • Chlorine is more effective than UV irradiation in removing ARGs from MWTP effluent. • The chlorination reaction followed the second-order reaction kinetic model. • Higher NH{sub 3}–N contents result in lower ARGs removal in the chlorination process. • FC is more effective than CC on the inactivation of ARGs. • UV irradiation followed by chlorination shows high efficiency in removing ARGs.

  17. Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

    Energy Technology Data Exchange (ETDEWEB)

    Arantes, C., E-mail: csilva@inmetro.gov.br [Divisão de Metrologia de Materiais, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Xerém 25250-020, Duque de Caxias, RJ (Brazil); Mendes, L.A.V. [Instituto de Física, Universidade Federal da Bahia, Ondina, 40210-340 Salvador, BA (Brazil); Pinho, R.R. [Departamento de Física-ICE, Universidade Federal de Juiz de Fora, Campus Universitário, 36036-330 Juiz de Fora, MG (Brazil); Ferreira, M. [PEMM/COPPE, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-972 Rio de Janeiro, RJ (Brazil); Souza, G.G.B. de; Rocha, A.B.; Rocco, M.L.M. [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-909 Rio de Janeiro, RJ (Brazil)

    2013-03-29

    Highlights: ► PVC and PVDC were studied by PSID and NEXAFS techniques at the Chlorine 1s-edge. ► PVC film presented isotope ratio of 3:1 in the PSID spectrum. ► Cl{sup +} ion yield curves reproduce the photoabsorption spectrum for both polymers. ► Site-selectivity of C–Cl bond breaking due to an efficient spectator Auger decay. - Abstract: Photon stimulated ion desorption (PSID) and Near-edge X-ray absorption fine structure (NEXAFS) studies have been performed on poly(vinyl chloride) (PVC) and poly(vinyl dichloride) (PVDC) around the chlorine 1s-edge. Experiments were performed using a synchrotron source operating in the single-bunch mode and a time-of-flight mass spectrometry for ion analysis. Cl{sup +} ion yields, as a function of the photon energy, reproduce the photoabsorption spectrum, showing significant increase at the 1s-resonance. Edge-jump ratios, defined as the ratio between edge-jumps (intensity ratio of the yields between above and below the absorption edge) of two different transitions, for Cl{sup +} ion yields were much higher than the equivalent electron yields, indicating site-selectivity in C–Cl bond breaking for both polymers, as a result of efficient spectator Auger decay. The expected isotope ratio of 3:1 for chlorine was measured for PVC. The interpretation of the NEXAFS spectrum was assisted by quantum mechanical calculations at a multireference perturbation theory level.

  18. Ficusmicrochlorin A-C, two new methoxy lactone chlorins and an anhydride chlorin from the leaves of Ficus microcarpa.

    Science.gov (United States)

    Lin, Huan-You; Chiu, Hsi-Lin; Lu, Te-Ling; Tzeng, Chih-Ying; Lee, Tzong-Huei; Lee, Ching-Kuo; Shao, Yi-Yuan; Chen, Chiy-Rong; Chang, Chi-I; Kuo, Yueh-Hsiung

    2011-01-01

    Two new methoxy lactone chlorins ficusmicrochlorin A (1) and ficusmicrochlorin B (2), and one new anhydride chlorin ficusmicrochlorin C (3), along with eight known pheophytins were isolated from the leaves of Ficus microcarpa. Their structures were determined by the extensive 1D- and 2D-NMR techniques. New pheophytin compound was rarely obtained from natural sources. In the past ten years, only three new natural pheophytins were characterized.

  19. Occurrence, fate and risk assessment of parabens and their chlorinated derivatives in an advanced wastewater treatment plant.

    Science.gov (United States)

    Li, Wenhui; Shi, Yali; Gao, Lihong; Liu, Jiemin; Cai, Yaqi

    2015-12-30

    In the present study, parabens, p-hydroxybenzoic acid (PHBA) and chlorinated derivatives, were simultaneously determined in wastewater and sludge samples along the whole process in an advanced wastewater treatment plant (WWTP). Nine target compounds were detected in this WWTP, and methylparaben and PHBA were the dominant compounds in these samples. It is noteworthy that octylparaben with longer chain was firstly detected in this work. Mass balance results showed that 91.8% of the initial parabens mass loading was lost mainly due to degradation, while the contribution of sorption and output of primary and excess sludge was much less (7.5%), indicating that biodegradation played a significant role in the removal of parabens during the conventional treatment process. Specifically, parabens were mainly degraded in the anaerobic tank, and PHBA could be effectively removed at high rates after the advanced treatment. However, both biodegradation and adsorption accounted for minor contribution to the removal of chlorinated parabens during conventional treatment process, and they were only scantly removed by conventional treatment (33.9-40.7%) and partially removed by advanced treatment (59.2-82.8%). Risk assessment indicated that parabens and their chlorinated derivatives in second and tertiary effluent are not likely to produce biological effects on aquatic ecosystems.

  20. Decontamination of a drinking water pipeline system contaminated with adenovirus and Escherichia coli utilizing peracetic acid and chlorine.

    Science.gov (United States)

    Kauppinen, Ari; Ikonen, Jenni; Pursiainen, Anna; Pitkänen, Tarja; Miettinen, Ilkka T

    2012-09-01

    A contaminated drinking water distribution network can be responsible for major outbreaks of infections. In this study, two chemical decontaminants, peracetic acid (PAA) and chlorine, were used to test how a laboratory-scale pipeline system can be cleaned after simultaneous contamination with human adenovirus 40 (AdV40) and Escherichia coli. In addition, the effect of the decontaminants on biofilms was followed as heterotrophic plate counts (HPC) and total cell counts (TCC). Real-time quantitative polymerase chain reaction (qPCR) was used to determine AdV40 and plate counting was used to enumerate E. coli. PAA and chlorine proved to be effective decontaminants since they decreased the levels of AdV40 and E. coli to below method detection limits in both water and biofilms. However, without decontamination, AdV40 remained present in the pipelines for up to 4 days. In contrast, the concentration of cultivable E. coli decreased rapidly in the control pipelines, implying that E. coli may be an inadequate indicator for the presence of viral pathogens. Biofilms responded to the decontaminants by decreased HPCs while TCC remained stable. This indicates that the mechanism of pipeline decontamination by chlorine and PAA is inactivation rather than physical removal of microbes.