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Sample records for toluene xylene styrene

  1. All rights reserved Competitive Adsorption of Xylene and Toluene on ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2018-03-23

    Mar 23, 2018 ... organic solvents (diesel, kerosene, gasoline, toluene and m-xylene), with and without agitation. The result showed that modified magnesium bentonite swelled more than the unmodified and the order of the swelling factor is; m- xylene > toluene > gasoline > diesel > DPK > water. However, when the assay ...

  2. Metabolism of Benzene, Toluene, and Xylene Hydrocarbons in Soil†

    OpenAIRE

    Tsao, C.-W.; Song, H.-G.; Bartha, R.

    1998-01-01

    Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed system that automatically replenished any O2 consumed. The decrease in solvent vapors and the produ...

  3. Degradation of toluene and m-xylene and transformation of o-xylene by denitrifying enrichment cultures.

    OpenAIRE

    Evans, P J; Mang, D T; Young, L Y

    1991-01-01

    Seven different sources of inocula that included sediments, contaminated soils, groundwater, process effluent, and sludge were used to establish enrichment cultures of denitrifying bacteria on benzene, toluene, and xylenes in the absence of molecular oxygen. All of the enrichment cultures demonstrated complete depletion of toluene and partial depletion of o-xylene within 3 months of incubation. The depletion of o-xylene was correlated to and dependent on the metabolism of toluene. No losses o...

  4. Degradation of toluene and m-xylene and transformation of o-xylene by denitrifying enrichment cultures.

    Science.gov (United States)

    Evans, P J; Mang, D T; Young, L Y

    1991-01-01

    Seven different sources of inocula that included sediments, contaminated soils, groundwater, process effluent, and sludge were used to establish enrichment cultures of denitrifying bacteria on benzene, toluene, and xylenes in the absence of molecular oxygen. All of the enrichment cultures demonstrated complete depletion of toluene and partial depletion of o-xylene within 3 months of incubation. The depletion of o-xylene was correlated to and dependent on the metabolism of toluene. No losses of benzene, p-xylene, or m-xylene were observed in these initial enrichment cultures. However, m-xylene was degraded by a subculture that was incubated on m-xylene alone. Complete carbon, nitrogen, and electron balances were determined for the degradation of toluene and m-xylene. These balances showed that these compounds were mineralized with greater than 50% conversion to CO2 and significant assimilation into biomass. Additionally, the oxidation of these compounds was shown to be dependent on nitrate reduction and denitrification. These microbial degradative capabilities appear to be widespread, since the widely varied inoculum sources all yielded similar results. PMID:2014990

  5. Detection of benzene, toluene, ethyl benzene, and xylenes (BTEX) using toluene dioxygenase-peroxidase coupling reactions.

    Science.gov (United States)

    Xu, Zhaohui; Mulchandani, Ashok; Chen, Wilfred

    2003-01-01

    We have developed a simple, whole-cell bioassay for the detection of bioavailable benzene, toluene, ethyl benzene, and xylenes (BTEX) and similar compounds. A genetically engineered E. coli strain expressing toluene dioxygenase (TDO) and toluene dihydrodiol dehydrogenase (TodD) was constructed, enabling the conversion of BTEX into their respective catechols, which were quickly converted into colored products by a horseradish peroxidase (HRP)-coupled reaction. The intensity of the color formation was correlated to concentrations of the BTEX compounds. Under the optimized conditions, a detection limit (defined as three times the standard deviation of the response obtained from the blank) of 10, 10, 20, and 50 microM was observed for benzene, toluene, ethyl benzene, and xylene, respectively. The bioassay was selective toward BTEX-related compounds with no interference observed with commonly used pesticides, herbicides, and organic solvent. The bioassay was very stable with little change in response over a 10-week period. The excellent stability suggests that the reported bioassay may be suitable for field monitoring of BTEX to identify and track contaminated water and follow the bioremediation progress.

  6. Accumulation and turnover of metabolites of toluene and xylene in nasal mucosa and olfactory bulb in the mouse

    Energy Technology Data Exchange (ETDEWEB)

    Ghantous, H.; Dencker, L.; Danielsson, B.R.G (Department of Toxicology, Uppsala University, Uppsala (Sweden)); Gabrielsson, J. (Department of Biopharmaceutics and Pharmacokinetics, Uppsala University, Uppsala (Sweden)); Bergman, K. (Toxicology Laboratory, National Swedish Food Administration, Uppsala (Sweden))

    1990-01-01

    Autoradiography of male mice following inhalation of the radioactively labelled solvents, toluene, xylene, and styrene, revealed an accumulation of non-volatile metabolites in the nasal mucosa and olfactory bulb of the brain. Since no accumulation occurred after benzene inhalation, it was assumed that the activity represented aromatic acids, which are known metabolites of these solvents. This was supported by the finding that also radioactive benzoic acid (main metabolite of toluene) and salicylic acid accumulated in the olfactory bulb. High-performance liquid chromatography revealed that after toluene inhalation (for 1 hr), nasal mucosa and olfactory bulb contained mainly benzoic acid, with a strong accumulation in relation to blood plasma, and considerably less of its blycine conjugate, hippuric acid. After xylene inhalation, on the other hand, methyl hippuric acid dominated over the non-conjugated metabolite, toluic acid. The results indicate a specific, possibly axonal flow-mediated transport of aromatic acids from the nasal mucosa to the olfactory lobe of the brain. The toxicological significance of these results remains to be studied. (author).

  7. Adsorption of BTX (benzene, toluene, o-xylene, and p-xylene) from aqueous solutions by modified periodic mesoporous organosilica.

    Science.gov (United States)

    Moura, Cícero P; Vidal, Carla B; Barros, Allen L; Costa, Luelc S; Vasconcellos, Luiz C G; Dias, Francisco S; Nascimento, Ronaldo F

    2011-11-15

    The capacity of a periodic mesoporous organosilica (PMO) to adsorb the aromatic compounds benzene, toluene, o-, and p-xylenes (BTX), which are usually present in produced waters, was investigated under both column and batch processes. The PMO was synthesized by condensation of 1,4 bis(triethoxisilyl)benzene (BTEB) under acidic conditions by using structure-directing agent (SDA) Pluronic P123 in the presence of KCl. Thermogravimetric analysis showed that the presence of the surfactant decreases the thermal stability of the PMO. The small-angle X-ray diffraction pattern, as well as the nitrogen adsorption/desorption isotherm measurements, revealed that the synthesized material has a crystalline structure, with hexagonally-ordered cylindrical mesopores. The adsorption kinetics study indicated an adsorption equilibrium time of 50 min and also showed that the data best fitted the pseudo-first order kinetic model. The intraparticle diffusion model was also tested and pointed to the occurrence of such process in all cases. Both Langmuir and Temkin models best represented the adsorption isotherms of toluene; Langmuir and Redlich-Peterson models best represented the data obtained for the other compounds. Adsorption capacity decreases in the order benzene>o-xylene>p-xylene>toluene. Satisfactory results were observed in the application of the synthesized PMO for the removal of BTX from aqueous solution. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Biocomplementation of SVE to achieve clean up goals in soils contaminated with toluene and xylene

    DEFF Research Database (Denmark)

    Soares, Antonio; Pinho, Maria Teresa; Albergaria, José Tomás

    2013-01-01

    aimed to study the combination of these two technologies in order to verify the achievement of the legal clean-up goals in soil remediation projects involving seven different simulated soils separately contaminated with toluene and xylene. The remediations consisted of the application of SVE followed...... by biostimulation. The results show that the combination of these two technologies is effective and manages to achieve the clean-up goals imposed by the Spanish Legislation. Under the experimental conditions used in this work, SVE is sufficient for the remediation of soils, contaminated separately with toluene...... and xylene, with organic matter contents (OMC) below 4 %. In soils with higher OMC, the use of BR, as a complementary technology, and when the concentration of contaminant in the gas phase of the soil reaches values near 1 mg/L, allows the achievement of the clean-up goals. The OMC was a key parameter...

  9. Biocomplementation of SVE to achieve clean-up goals in soils contaminated with toluene and xylene.

    Science.gov (United States)

    Soares, António Alves; Pinho, Maria Teresa; Albergaria, José Tomás; Domingues, Valentina; da Conceição Alvim-Ferraz, Maria; Delerue-Matos, Cristina

    2013-10-01

    Soil vapor extraction (SVE) and bioremediation (BR) are two of the most common soil remediation technologies. Their application is widespread; however, both present limitations, namely related to the efficiencies of SVE on organic soils and to the remediation times of some BR processes. This work aimed to study the combination of these two technologies in order to verify the achievement of the legal clean-up goals in soil remediation projects involving seven different simulated soils separately contaminated with toluene and xylene. The remediations consisted of the application of SVE followed by biostimulation. The results show that the combination of these two technologies is effective and manages to achieve the clean-up goals imposed by the Spanish Legislation. Under the experimental conditions used in this work, SVE is sufficient for the remediation of soils, contaminated separately with toluene and xylene, with organic matter contents (OMC) below 4 %. In soils with higher OMC, the use of BR, as a complementary technology, and when the concentration of contaminant in the gas phase of the soil reaches values near 1 mg/L, allows the achievement of the clean-up goals. The OMC was a key parameter because it hindered SVE due to adsorption phenomena but enhanced the BR process because it acted as a microorganism and nutrient source.

  10. Simulating Retention in Gas-Liquid Chromatography: Benzene, Toluene, and Xylene Solutes

    Energy Technology Data Exchange (ETDEWEB)

    WICK,COLLIN D.; MARTIN,MARCUS G.; SIEPMANN, J. ILJA; SCHURE,MARK R.

    2000-07-12

    Accurate predictions of retention times, retention indices, and partition constants are a long sought-after goal for theoretical studies in chromatography. Although advances in computational chemistry have improved the understanding of molecular interactions, little attention has been focused on chromatography, let alone calculations of retention properties. Configurational-bias Monte Carlo simulations in the isobaric-isothermal Gibbs ensemble were used to investigate the partitioning of benzene, toluene, and the three xylene isomers between a squalane liquid phase and a helium vapor phase. The united-atom representation of the TraPPE (Transferable Potentials for Phase Equilibria) force field was used for all solutes and squalane. The Gibbs free energies of transfer and Kovats retention indices of the solutes were calculated directly from the partition constants (which were averaged over several independent simulations). While the calculated Kovats indices of benzene and toluene at T = 403 K are significantly higher than their experimental counterparts, much better agreement is found for the xylene isomers at T = 365 K.

  11. Volumetric, Viscometric and Excess Properties of Binary Mixtures of 1-Iodobutane with Benzene, Toluene, o-Xylene, m-Xylene, p-Xylene, and Mesitylene at Temperatures from 303.15 to 313.15 K

    OpenAIRE

    Sharma, Sangita; Thakkar, Khushbu; Patel, Paras; Makavana, Madhuresh

    2013-01-01

    Densities and viscosities have been determined for binary mixtures of 1-iodobutane with benzene, toluene, o-xylene, m-xylene, p-xylene, and mesitylene at 303.15, 308.15, and 313.15 K for the entire composition range at atmospheric pressure. The excess molar volumes, , deviations in viscosity, Δη, and excess Gibbs’ free energy of activation flow, Δ have been calculated from the experimental values. The experimental data were fitted to Redlich-Kister polynomial equation. The variations of these...

  12. Adsorption of benzene, toluene, and xylene by two tetramethylammonium-smectites having different charge densities

    Science.gov (United States)

    Lee, Jiunn-Fwu; Mortland, Max M.; Chiou, Cary T.; Kite, Daniel E.; Boyd, Stephen A.

    1990-01-01

    A high-charge smectite from Arizona [cation-exchange capacity (CEC) = 120 meq/100 g] and a low-charge smectite from Wyoming (CEC = 90 meq/100 g) were used to prepare homoionic tetramethylammonium (TMA)-clay complexes. The adsorption of benzene, toluene, and o-xylene as vapors by the dry TMA-clays and as solutes from water by the wet TMA-clays was studied. The adsorption of the organic vapors by the dry TMA-smectite samples was strong and apparently consisted of interactions with both the aluminosilicate mineral surfaces and the TMA exchange ions in the interlayers. In the adsorption of organic vapors, the closer packing of TMA ions in the dry high-charge TMA-smectite, compared with the dry low-charge TMA-smectite, resulted in a somewhat higher degree of shape-selective adsorption of benzene, toluene, and xylene. In the presence of water, the adsorption capacities of both samples for the aromatic compounds were significantly reduced, although the uptake of benzene from water by the low-charge TMA-smectite was still substantial. This lower sorption capacity was accompanied by increased shape-selectivity for the aromatic compounds. The reduction in uptake and increased selectivity was much more pronounced for the water-saturated, high-charge TMA-smectite than for the low-charge TMA-smectite. Hydration of the TMA exchange ions and/or the mineral surfaces apparently reduced the accessibility of the aromatic molecules to interlamellar regions. The resulting water-induced sieving effect was greater for the high-charge TMA-smectite due to the higher density of exchanged TMA-ions. The low-charge Wyoming TMA-smectite was a highly effective adsorbent for removing benzene from water and may be useful for purifying benzene-contaminated water.

  13. Conversion of toluene to benzene and mixed xylenes on old Thermofor Catalytic Cracking Units (TCC) in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Alfonso; Usachev, Nikolai Y.; Kalinin, Valera P. [Russian Academy of Sciences, Moscow (Russian Federation). Zelinsky Institute of Organic Chemistry]. E-mails: romero@orc.ru; ny@ioc.ac.ru

    2004-07-01

    World demand on toluene was in regression during the last years due to environmental and economical reasons, and there is a surplus of this compound from the processing to the petrochemical products. Disproportionation and transalkylation for the production of benzene and xylenes from toluene are now important industrial processes (Ikai Wang, 1999.). We analyze here the possibility of processing toluene on the Russian 43-102 'Houdry' type continuous Catalytic Cracking units (TCC), by studying the behaviour of EMCAT-100 catalyst on the disproportionation of toluene under the VHSV, temperature and catalyst/feed mass ratio characteristic for 43-102 facilities. Our previous results show that toluene disproportionation could be carried out on the Russian TCC units. (author)

  14. Safety assessment of xylene sulfonic acid, toluene sulfonic acid, and alkyl aryl sulfonate hydrotropes as used in cosmetics.

    Science.gov (United States)

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

    2011-12-01

    Xylene sulfonic acid, toluene sulfonic acid, and alkyl aryl sulfonate hydrotropes used in cosmetics as surfactants, hydrotropes, were reviewed in this safety assessment. The similar structure, properties, functions, and uses of these ingredients enabled grouping them and using the available toxicological data to assess the safety of the entire group. The Cosmetic Ingredient Review Expert Panel reviewed relevant animal and human data related to these ingredients. The panel concluded that xylene sulfonic acid and alkyl aryl sulfonate hydrotropes are safe as cosmetic ingredients in the present practices of use and concentrations as described in this safety assessment, when formulated to be nonirritating.

  15. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations; Exposition par inhalation au benzene, toluene, ethylbenzene et xylenes (BTEX) dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  16. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  17. Determination of Xylene and Toluene by Solid-Phase Microextraction Using Au Nanoparticles-Thiol Silane Film Coupled to Ion Mobility Spectrometry.

    Science.gov (United States)

    Allafchian, Ali Reza; Akhgar, Ava; Ielbeigi, Vahideh; Tabrizchi, Mahmoud

    2016-11-01

    A simple, rapid and sensitive method for analysis of xylene and toluene was developed using the solid-phase microextraction (SPME) combined with ion mobilityspectrometry (IMS). Gold nanoparticles-thiol silane film (Au NPs-TSF) was applied as a newsorbent for SPME. Thiol silane film was formed on the surface of a stainless steel wire through incorporating Au nanoparticles during synthesis using sol-gel technique. The extraction properties of the fiber to xylene and toluene were examined, using a SPME device and thermal desorption ininjection port of IMS. The calibration graphs were linear in the range of 1.10-32.0 and 16.0-112.0 ppb for xylene and toluene, respectively. The detection limits for xylene and toluene were 0.7 and 8.0 ppb, respectively. The proposed method was applied without any considerable sample pretreatment and it was found to be simple enough to be strongly recommended for real sample analysis.

  18. Degradation of toluene, ethylbenzene, and xylene using heat and chelated-ferrous iron activated persulfate oxidation

    Science.gov (United States)

    Mondal, P.; Sleep, B.

    2014-12-01

    Toluene, ethylbenze, and xylene (TEX) are common contaminants in the subsurface. Activated persulfate has shown promise for degrading a wide variety of organic compounds. However, studies of persulfate application for in situ degradation of TEX and effects on the subsequent bioremediation are limited. In this work, degradation studies of TEX in aqueous media and soil are being conducted using heat activated and chelated-ferrous iron activated persulfate oxidation in batch and flow-through column experiments. In the batch experiments, sodium persulfate is being used at different concentrations to provide an initial persulfate to TEX molar ratios between 10:1 and 100:1. Sodium persulfate solutions are being activated at 20, 37, 60, and 80 oC temperatures for the heat activated oxidation. For the chelated-ferrous iron activated oxidation, ferrous iron and citric acid, both are being used at concentration of 5 mM. In the experiments with soil slurry, a soil to water ratio of 1 to 5 is being used. Flow through water saturated column experiments are being conducted with glass columns (45 cm in length and 4 cm in diameter) uniformly packed with soils, and equilibrated with water containing TEX at the target concentrations. Both the heat activation and chelated-ferrous iron activation of persulfate are being employed in the column experiments. Future experiments are planned to determine the suitability of persulfate oxidation of TEX on the subsequent biodegradation using batch microcosms containing TEX degrading microbial cultures. In these experiments, the microbial biomass will be monitored using total phospholipids, and the microbial community will be determined using quantitative real-time polymerase chain reaction (qPCR) on the extracted DNA. This study is expected to provide suitable operating conditions for in situ chemical oxidation of TEX with activated persulfate followed by bioremediation.

  19. Substrate Interactions during the Biodegradation of Benzene, Toluene, Ethylbenze, and Xylene (BTEX) Hydrocarbons by the Fungus Cladophialophora sp. Strain T1

    NARCIS (Netherlands)

    Prenafeta-Boldú, F.X.; Vervoort, J.; Grotenhuis, J.T.C.; Groenestijn, van J.W.

    2002-01-01

    The soil fungus Cladophialophora sp. strain T1 (= ATCC MYA-2335) was capable of growth on a model water-soluble fraction of gasoline that contained all six BTEX components (benzene, toluene, ethylbenzene, and the xylene isomers). Benzene was not metabolized, but the alkylated benzenes (toluene,

  20. A chromosomally based tod-luxCDABE whole-cell reporter for benzene, toluene, ethybenzene, and xylene (BTEX) sensing

    International Nuclear Information System (INIS)

    Applegate, B.M.; Kehrmeyer, S.R.; Sayler, G.S.

    1998-01-01

    A tod-luxCDABE fusion was constructed and introduced into the chromosome of Pseudomonas putida F1, yielding the strain TVA8. This strain was used to examine the induction of the tod operon when exposed to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and aqueous solutions of JP-4 jet fuel constituents. Since this system contained the complete lux cassette (luxCDABE), bacterial bioluminescence in response to putative chemical inducers of the tod operon was measured on-line in whole cells without added aldehyde substrate. There was an increasing response to toluene concentrations from 30 microg/liter to 50 mg/liter, which began to saturate at higher concentrations. The detection limit was 30 microg/liter. There was a significant light response to benzene, m- and p-xylenes, phenol, and water-soluble JP-4 jet fuel components, but there was no bioluminescence response upon exposure to o-xylene. The transposon insertion was stable and had no negative effect on cell growth

  1. Evaluation of neuropsychological symptoms and exposure to benzene, toluene and xylene among two different furniture worker groups in Izmir.

    Science.gov (United States)

    Mandiracioglu, Aliye; Akgur, Serap; Kocabiyik, Nesrin; Sener, Ufuk

    2011-10-01

    This study was conducted to determine whether there was any exposure to toluene, xylene and benzene and to assess the health impact of these solvents on workers in furniture enterprises in Karabaglar, Izmir. This cross-sectional study covered furniture enterprises in Karabaglar, Izmir. This study was comprised of an exposed group consisting of workers engaged in painting and varnishing and therefore exposed either directly or indirectly toluene, xylene and benzene in the workplace and the non-exposed group engaged in other aspects of production. While a total of 261 individuals completed questionnaires, 210 workers agreed to provide blood samples. Blood solvents levels were determined using gas chromatograph at Ege University, Intoxication Research and Application Centre. The modified EUROQUEST questionnaire was used to assess neuropsychological symptoms and neurological and general examination were performed. Occupational and exposure history, demographic and work-related information was collected. In this study of workers, blood toluene and benzene levels were found to be significantly higher among those engaged in painting and varnishing compared to those who perform other tasks. The average blood toluene and benzene concentrations among exposed workers were 6.95 times and 1.64 times respectively higher than those in the nonexposed groups. Smokers and participants who worked in excess of 8 hours/day had higher blood toluene and benzene levels. The most frequently work-related health complaints were back pain, allergies and asthma. No differences were found in the average scores in the neuropsychological symptoms questionnaire between exposed and non-exposed groups. Neurological examination of two individuals with these complaints revealed a loss of reflexes. The workers were unaware that they were being exposed to solvents at work. Tobacco smoke is a major source of internal exposure to benzene. Improving working conditions in furniture work places is a priority.

  2. Quantitative detection of benzene in toluene- and xylene-rich atmospheres using high-kinetic-energy ion mobility spectrometry (IMS).

    Science.gov (United States)

    Langejuergen, Jens; Allers, Maria; Oermann, Jens; Kirk, Ansgar; Zimmermann, Stefan

    2014-12-02

    One major drawback of ion mobility spectrometry (IMS) is the dependence of the response to a certain analyte on the concentration of water or the presence of other compounds in the sample gas. Especially for low proton affine analytes, e.g., benzene, which often exists in mixtures with other volatile organic compounds, such as toluene and xylene (BTX), a time-consuming preseparation is necessary. In this work, we investigate BTX mixtures using a compact IMS operated at decreased pressure (20 mbar) and high kinetic ion energies (HiKE-IMS). The reduced electric field in both the reaction tube and the drift tube can be independently increased up to 120 Td. Under these conditions, the water cluster distribution of reactant ions is shifted toward smaller clusters independent of the water content in the sample gas. Thus, benzene can be ionized via proton transfer from H3O(+) reactant ions. Also, a formation of benzene ions via charge transfer from NO(+) is possible. Furthermore, the time for interaction between ions and neutrals of different analytes is limited to such an extent that a simultaneous quantification of benzene, toluene, and xylene is possible from low ppbv up to several ppmv concentrations. The mobility resolution of the presented HiKE-IMS varies from R = 65 at high field (90 Td) to R = 73 at lower field (40 Td) in the drift tube, which is sufficient to separate the analyzed compounds. The detection limit for benzene is 29 ppbv (2 s of averaging) with 3700 ppmv water, 12.4 ppmv toluene, and 9 ppmv xylene present in the sample gas. Furthermore, a less-moisture-dependent benzene measurement with a detection limit of 32 ppbv with ca. 21 000 ppmv (90% relative humidity (RH) at 20 °C) water present in the sample gas is possible evaluating the signal from benzene ions formed via charge transfer.

  3. Evaluation of the occupational risk for exposition to Benzene, Toluene and Xylene in a paintings industry in Bogota

    International Nuclear Information System (INIS)

    Rubiano D, Maria del Pilar; Marciales C, Clara; Duarte A, Martha

    2002-01-01

    It was determined Benzene, Toluene and Xylene (BTX) levels in air from paint manufacture assigned to Instituto Colombiano de Seguro Social with the purpose to evaluate the occupational hazard caused by the use of these solvents. These results were compared with the threshold limit value (TLV). It was selected as sampling strategy, the methodology of partial period with consecutive samples and charcoal tubes as adsorbent of solvents. The extraction was realized with carbon disulfide and it was used gas chromatography with FID as analysis method. It was found that the method is highly selective because in presence of the others ten solvents, utilized in paint manufacture, were obtained a good separation for BTX. The precision, expressed a variance coefficient, was lower than 10%, the accuracy varied between 85 and 99 % for the three solvents. The airborne concentration found was between no detectable and 55,1 mg/m 3 for benzene, 18,3 and 253 mg/m 3 for toluene and 11,8 and 122,2 mg/m 3 for xylene. The corrected TLV values for benzene, toluene and xylenes according to the brief and scale model for the ten hours shift were 1,1, 132 and 304 mg/m 3 respectively. It was found occupational risk for benzene in some workplaces; this one is worried because benzene is not used as raw material for the paint manufacture. It was determinate that exist occupational risk in almost every workplace of the industry when it is considered the mixture of the three solvents

  4. Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX)

    OpenAIRE

    Muliane Ulfi; Lestari Puji

    2018-01-01

    Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX) tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW) having production capacity 4600-ton clinker/day (max. 5000 ton/day) and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day). The concentration of V...

  5. An analysis of factors that influence personal exposure to toluene and xylene in residents of Athens, Greece

    Directory of Open Access Journals (Sweden)

    Linos Athena

    2006-02-01

    Full Text Available Abstract Background Personal exposure to pollutants is influenced by various outdoor and indoor sources. The aim of this study was to evaluate the exposure of Athens citizens to toluene and xylene, excluding exposure from active smoking. Methods Passive air samplers were used to monitor volunteers, their homes and various urban sites for one year, resulting in 2400 measurements of toluene and xylene levels. Since both indoor and outdoor pollution contribute significantly to human exposure, volunteers were chosen from occupational groups who spend a lot of time in the streets (traffic policemen, bus drivers and postmen, and from groups who spend more time indoors (teachers and students. Data on individual and house characteristics were obtained using a questionnaire completed at the beginning of the study; a time-location-activity diary was also completed daily by the volunteers in each of the six monitoring campaigns. Results Average personal toluene exposure varied over the six monitoring campaigns from 53 to 80 μg/m3. Urban and indoor concentrations ranged from 47 – 84 μg/m3 and 30 – 51 μg/m3, respectively. Average personal xylene exposure varied between 56 and 85 μg/m3 while urban and indoor concentrations ranged from 53 – 88 μg/m3 and 27 – 48 μg/m3, respectively. Urban pollution, indoor residential concentrations and personal exposures exhibited the same pattern of variation during the measurement periods. This variation among monitoring campaigns might largely be explained by differences in climate parameters, namely wind speed, humidity and amount of sunlight. Conclusion In Athens, Greece, the time spent outdoors in the city center during work or leisure makes a major contribution to exposure to toluene and xylene among non-smoking citizens. Indoor pollution and means of transportation contribute significantly to individual exposure levels. Other indoor residential characteristics such as recent painting and mode of heating

  6. Volumetric, Viscometric and Excess Properties of Binary Mixtures of 1-Iodobutane with Benzene, Toluene, o-Xylene, m-Xylene, p-Xylene, and Mesitylene at Temperatures from 303.15 to 313.15 K

    Directory of Open Access Journals (Sweden)

    Sangita Sharma

    2013-01-01

    Full Text Available Densities and viscosities have been determined for binary mixtures of 1-iodobutane with benzene, toluene, o-xylene, m-xylene, p-xylene, and mesitylene at 303.15, 308.15, and 313.15 K for the entire composition range at atmospheric pressure. The excess molar volumes, , deviations in viscosity, Δη, and excess Gibbs’ free energy of activation flow, Δ have been calculated from the experimental values. The experimental data were fitted to Redlich-Kister polynomial equation. The variations of these parameters with composition of the mixtures and temperature have been discussed in terms of molecular interactions occurring in these mixtures. Further, the viscosities of these binary mixtures were calculated theoretically from their corresponding pure component data by using empirical relations like Bingham, Arrhenius and Eyring, Kendall and Munroe, Hind, Katti and Chaudhari, Grunberg and Nissan, and Tamura and Kurata. Comparison of various interaction parameters has been expressed to explain the intermolecular interactions between iodobutane and selected hydrocarbons.

  7. Electrodeposited ZnO/ Zn Photo catalysts for the Degradation of Benzene-Toluene-Xylene Mixture in Aqueous Phase

    International Nuclear Information System (INIS)

    Ju, L.C.; Wan Azelee Wan Abu Bakar; Rusmidah Ali

    2012-01-01

    The recognition of the ability of volatile organic compounds, (VOCs) to pollute the ground water is now well documented. VOCs such as benzene, toluene and xylene from the petroleum industries processed water leaked through the underground old piping system into the soils and groundwater during its transportation to the wastewater plant. Photo catalysis have been used as a potential system in the degradation of VOCs in the wastewater. However, the powdered form photo catalysts that were used in various studies are difficult to be separated from the aqueous solution at the end of the treatment. Therefore, the main objective of this research is to prepare the electrodeposited photo catalysts for the degradation of aromatic hydrocarbon mixture, benzene-toluene-xylene (BTX) solution under UV light (354 nm). The concentrations of electrolyte and electrodeposition voltages used to prepare the photo catalysts were studied for their efficiency in the degradation. From the research, ZnO/ Zn prepared in 0.8 M NaOH and under 12 V possessed the best catalytic degradation performance by degrading 32.37 % of BTX in the solution. The ZnO/ Zn photo catalyst was characterized using X-ray Diffraction Techniques (XRD) which illustrated high crystallinity of Zn species and reasonably high amorphous phase of ZnO species. (author)

  8. Simulation of SOA formation and composition from oxidation of toluene and m-xylene in chamber experiments

    Science.gov (United States)

    Xu, J.; Liu, Y.; Nakao, S.; Cocker, D.; Griffin, R. J.

    2013-12-01

    Aromatic hydrocarbons contribute an important fraction of anthropogenic reactive volatile organic compounds (VOCs) in the urban atmosphere. Photo-oxidation of aromatic hydrocarbons leads to secondary organic products that have decreased volatilities or increased solubilities and can form secondary organic aerosol (SOA). Despite the crucial role of aromatic-derived SOA in deteriorating air quality and harming human health, its formation mechanism is not well understood and model simulation of SOA formation still remains difficult. The dependence of aromatic SOA formation on nitrogen oxides (NOx) is not captured fully by most SOA formation models. Most models predict SOA formation under high NOx levels well but underestimate SOA formation under low NOx levels more representative of the ambient atmosphere. Thus, it is crucial to investigate the NOx-dependent chemistry in aromatic photo-oxidation systems and correspondingly update SOA formation models. In this study, NOx-dependent mechanisms of toluene and m-xylene SOA formation are updated using the gas-phase Caltech Atmospheric Chemistry Mechanism (CACM) coupled to a gas/aerosol partitioning model. The updated models were optimized by comparing to eighteen University of California, Riverside United States Environmental Protection Agency (EPA) chamber experiment runs under both high and low NOx conditions. Correction factors for vapor pressures imply uncharacterized aerosol-phase association chemistry. Simulated SOA speciation implies the importance of ring-opening products in governing SOA formation (up to 40%~60% for both aromatics). The newly developed model can predict strong decreases of m-xylene SOA yield with increasing NOx. Speciation distributions under varied NOx levels implies that the well-known competition between RO2 + HO2 and RO2 + NO (RO2 = peroxide bicyclic radical) may not be the only factor influencing SOA formation. The reaction of aromatic peroxy radicals with NO competing with its self

  9. Theoretical study on the alkylation of o-xylene with styrene in AlCl3-ionic liquid catalytic system.

    Science.gov (United States)

    Cao, Bobo; Du, Jiuyao; Cao, Ziping; Sun, Haitao; Sun, Xuejun; Fu, Hui

    2017-06-01

    To explore sustainable catalysts with innovative mechanisms, the alkylation mechanism of o-xylene with styrene was studied using DFT method in AlCl 3 -ionic liquid catalytic system. The reaction pathway was consisted of CC coupling and a hydrogen shift, in which two transition states were found and further discussed. The reactive energy catalyzed by superelectrophilic AlCl 2 + (12.6kcal/mol) was distinctly lower than AlCl 3 (43.0kcal/mol), which was determined as the rate-determining step. Mulliken charge along IRC gave a comprehensive understanding of charge distribution and electron transfer in dynamic progress. Bond orders and AIM theory were used to study the nature of chemical bonds and the driving forces in different reaction stages. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Comparison of needle concentrator with SPME for GC determination of benzene, toluene, ethylbenzene, and xylenes in aqueous samples

    Energy Technology Data Exchange (ETDEWEB)

    Prikryl, P.; Sevcik, J. [Charles Univ., Prague (Czech Republic). Dept. of Analytical Chemistry; Kubinec, R.; Jurdakova, H.; Ostrovsky, I.; Sojak, L. [Comenius Univ., Bratislava (Slovakia). Chemical Inst.; Berezkin, V. [Russian Academy of Sciences, Moscow (Russian Federation). A.V. Topchiev Inst. of Petrochemical Synthesis

    2006-07-15

    A method of solventless extraction of volatile organic compounds from aqueous samples has been developed and validated. A new arrangement in which the internal volume of a needle capillary adsorption trap is completely filled with Porapak Q, as adsorbent material, and wet alumina, as a source of desorptive water vapor flow, is presented. The device has been used for head-space sampling of benzene, toluene, ethylbenzene, and xylenes (BTEX) from water samples and compared with solid-phase microextraction. Under the same sampling conditions the analytical characteristics of the device for the BTEX compounds are better than those of solid-phase microextraction. Limits of detection and quantification are below 0.5 {mu} g L{sup -1}. (orig.)

  11. Effect of pH and loading manner on the start-up period of peat biofilter degrading xylene and toluene mixture

    Czech Academy of Sciences Publication Activity Database

    Marek, J.; Páca, J.; Halecký, M.; Koutský, B.; Sobotka, Miroslav; Keshavarz, T.

    2001-01-01

    Roč. 46, č. 3 (2001), s. 205-209 ISSN 0015-5632 R&D Projects: GA ČR GA104/99/1623 Institutional research plan: CEZ:AV0Z5020903 Keywords : biofilter * xylene * toluene Subject RIV: EE - Microbiology, Virology Impact factor: 0.776, year: 2001

  12. On-line CO, CO2 emissions evaluation and (benzene, toluene, xylene) determination from experimental burn of tropical biomass.

    Science.gov (United States)

    Tawfiq, Mohammed F; Aroua, Mohamed Kheireddine; Sulaiman, Nik Meriam Nik

    2015-07-01

    Atmospheric pollution and global warming issues are increasingly becoming major environmental concerns. Fire is one of the significant sources of pollutant gases released into the atmosphere; and tropical biomass fires, which are of particular interest in this study, contribute greatly to the global budget of CO and CO2. This pioneer research simulates the natural biomass burning strategy in Malaysia using an experimental burning facility. The investigation was conducted on the emissions (CO2, CO, and Benzene, Toluene, Ethylbenzene, Xylenes (BTEX)) from ten tropical biomass species. The selected species represent the major tropical forests that are frequently subjected to dry forest fire incidents. An experimental burning facility equipped with an on-line gas analyzer was employed to determine the burning emissions. The major emission factors were found to vary among the species, and the specific results were as follows. The moisture content of a particular biomass greatly influenced its emission pattern. The smoke analysis results revealed the existence of BTEX, which were sampled from a combustion chamber by enrichment traps aided with a universal gas sampler. The BTEX were determined by organic solvent extraction followed by GC/MS quantification, the results of which suggested that the biomass burning emission factor contributed significant amounts of benzene, toluene, and m,p-xylene. The modified combustion efficiency (MCE) changed in response to changes in the sample moisture content. Therefore, this study concluded that the emission of some pollutants mainly depends on the burning phase and sample moisture content of the biomass. Copyright © 2015. Published by Elsevier B.V.

  13. Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX

    Directory of Open Access Journals (Sweden)

    Muliane Ulfi

    2018-01-01

    Full Text Available Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW having production capacity 4600-ton clinker/day (max. 5000 ton/day and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day. The concentration of VOCs emissions tends to be higher at the raw mill on rather than the raw mill off. At the raw mill on, concentration of total volatile organic carbon (VOCs emission from cement kiln stack feeding Solid AFR 1, biomass, Solid AFR 2, and mixture of Solid AFR and biomass is 16.18 mg/Nm3, 16.15 mg/Nm3, 9.02 mg/Nm3, and 14.11 mg/Nm3 respectively. The utilization of biomass resulted in the lower fraction of benzene and the higher fraction of xylenes in the total VOCs emission. Operating conditions such as thermal substitution rate, preheater temperature, and kiln speed are also likely to affect BTEX emissions.

  14. Phenomena Based Process Intensification of Toluene Methylation for Sustainable Para-xylene Production

    DEFF Research Database (Denmark)

    Anantasarn, Nateetorn; Babi, Deenesh Kavi; Suriyapraphadilok, Uthaiporn

    2016-01-01

    based method. Here, the flowsheet is decomposed into unit operations, tasks and phenomena that are analysed and selected in order to increase driving forces related to, for example, reaction and separation. The phenomena are then re-combined to fulfil tasks that are translated into intensified unit...... operations to generate more sustainable designs. An overview of the key concepts and framework are presented together with the results from a case study highlighting the application of the framework to the sustainable design of a production process for para-xylene, which is an important chemical utilized......The objective of this work is to generate more sustainable intensified process designs for the production of important chemicals in the petrochemical sector. A 3-stage approach is applied. In stage 1, the base case design is generated or selected from literature. In stage 2, the base case design...

  15. Determination of benzene, toluene, ethylbenzene and xylenes in air by solid phase micro-extraction/gas chromatography/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tumbiolo, Simonetta; Gal, Jean-Francois; Maria, Pierre-Charles [Universite de Nice-Sophia Antipolis, Laboratoire de Radiochimie, Sciences Analytiques et Environnement, Faculte des Sciences, Nice Cedex 2 (France); Zerbinati, Orfeo [Universita del Piemonte Orientale ' ' Amedeo Avogadro' ' , Dipartimento di Scienze e Tecnologie Avanzate, Alessandria (Italy)

    2004-11-01

    The aim of the study was to analyse BTEX compounds (benzene, toluene, ethylbenzene, xylenes) in air by solid phase micro-extraction/gas chromatography/mass spectrometry (SPME/GC/MS), and this article presents the features of the calibration method proposed. Examples of real-world air analysis are given. Standard gaseous mixtures of BTEX in air were generated by dynamic dilution. SPME sampling was carried out under non-equilibrium conditions using a Carboxen/PDMS fibre exposed for 30 min to standard gas mixtures or to ambient air. The behaviour of the analytical response was studied from 0 to 65 {mu}g/m{sup 3} by adding increasing amounts of BTEX to the air matrix. Detection limits range from 0.05 to 0.1 {mu}g/m{sup 3} for benzene, depending on the fibre. Inter-fibre relative standard deviations (reproducibility) are larger than 18%, although the repeatability for an individual fibre is better than 10%. Therefore, each fibre should be considered to be a particular sampling device, and characterised individually depending on the required accuracy. Sampling indoor and outdoor air by SPME appears to be a suitable short-delay diagnostic method for volatile organic compounds, taking advantage of short sampling time and simplicity. (orig.)

  16. Development of a versatile, easy and rapid atmospheric monitor for benzene, toluene, ethylbenzene and xylenes determination in air.

    Science.gov (United States)

    Esteve-Turrillas, Francesc A; Ly-Verdú, Saray; Pastor, Agustín; de la Guardia, Miguel

    2009-11-27

    A new procedure for the passive sampling in air of benzene, toluene, ethylbenzene and xylene isomers (BTEX) is proposed. A low-density polyethylene layflat tube filled with a mixture of solid phases provided a high versatility tool for the sampling of volatile compounds from air. Several solid phases were assayed in order to increase the BTEX absorption in the sampler and a mixture of florisil and activated carbon provided the best results. Direct head-space-gas chromatography-mass spectrometry (HS-GC-MS) measurement of the whole deployed sampler was employed for a fast determination of BTEX. Absorption isotherms were used to develop simple mathematical models for the estimation of BTEX time-weighted average concentrations in air. The proposed samplers were used to determine BTEX in indoor air environments and results were compared with those found using two reference methodologies: triolein-containing semipermeable membrane devices (SPMDs) and diffusive Radiello samplers. In short, the developed sampling system and analytical strategy provides a versatile, easy and rapid atmospheric monitor (VERAM).

  17. Infrared hollow waveguide sensors for simultaneous gas phase detection of benzene, toluene, and xylenes in field environments.

    Science.gov (United States)

    Young, Christina R; Menegazzo, Nicola; Riley, Andrew E; Brons, Cornelius H; DiSanzo, Frank P; Givens, Jacquelyn L; Martin, John L; Disko, Mark M; Mizaikoff, Boris

    2011-08-15

    Simultaneous and molecularly selective parts-per-billion detection of benzene, toluene, and xylenes (BTX) using a thermal desorption (TD)-FTIR hollow waveguide (HWG) trace gas sensor is demonstrated here for the first time combining laboratory calibration with real-world sample analysis in field. A calibration range of 100-1000 ppb analyte/N(2) was developed and applied for predicting the concentration of blinded environmental air samples within the same concentration range, and demonstrate close agreement with the validation method used here, GC-FID. The analyte concentration prediction capability of the TD-FTIR-HWG trace gas sensor also compares well with the industrial standard and other experimental techniques including GC-PID, ultrafast GC-FID, and GC-DMS, which were simultaneously operated in the field. With the advent of a quantum cascade laser with emission frequencies specifically tailored to efficiently overlap benzene absorption as the most relevant analyte, the overall sensor footprint could be considerably reduced to ultimately yield hand-held trace gas sensors facilitating direct and real-time detection of BTX in air down to low ppb levels.

  18. Dielectric properties of liquid systems: study of interactions in the systems carbon tetrachloride with benzene, toluene, and p-xylene

    Directory of Open Access Journals (Sweden)

    Adrián H. Buep

    2014-12-01

    Full Text Available Intermolecular associations in liquid systems of non-polar and slightly polar compounds were studied through excess molar volumes (VEM and excess dielectric properties (εE and n2ED for mixtures of carbon tetrachloride (CCl4 with benzene (C6H6, toluene (C6H5CH3, and p-xylene (p-(CH32C6H4. These excess properties were calculated from measurements of density (ρ, static permittivity (ε, and refractive index (nD over the whole range of concentrations at 298.15 K. The values of the excess dielectric properties for these mixtures were fitted in two different ways, one through least squares using the Redlich–Kister equation and the other using a model developed to explain deviations from ideality. The first fit was found to be descriptive while the second gave the equilibrium constant values for the interaction products actually formed in the mixtures and the respective electronic polarizabilities and dipole moments, indicating the existence of interaction products.

  19. Evaluation of seawater contamination with benzene, toluene and xylene in the Ubatuba north coast, SP region, and study of their removal by ionizing radiation

    International Nuclear Information System (INIS)

    Almeida, Kelly Cristina Santana de

    2006-01-01

    A major concern with leaking petroleum is the environmental contamination by the toxic and low water-soluble components such as benzene, toluene, and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. The objective of this study was to evaluate the contamination of seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene, and xylene, and their removal by the exposure to the ionizing radiation. The studied region was Ubatuba region, SP, between 23 deg 26'S and 23 deg 46'S of latitude and 45 deg 02'W and 45 deg 11'W of longitude, area of carry and output of petroleum, and samples were collected from November, 2003 to July, 2005. For BTX in seawater analysis, the Purge and Trap concentrator with FIDGC detector showed significantly higher sensibility than Head Space concentrator with MSGC detector. The minimal detected limits (MDL) obtained at FIDGC were of 0.50 μg/L for benzene, 0.70 μg/L for toluene, and 1.54 μg/L for xylene, and the obtained experimental variability was 15%. While the concentrator type Headspace system with MS detector showed higher MLD, about of 9.30 mg/L for benzene, 8.50 mg/L for toluene, and 9.80 mg/L for xylene, and 10% of experimental variability. In the studied area the benzene concentration varied from 1.0 μg/L to 2.0 μg/L, the concentration of toluene varied from 60 Co, presented a removal from 10% to 40% of benzene at 20 kGy absorbed doses and concentration of 35.1 mg/L and 70.2 mg/L, respectively; from 20% to 60% of toluene removal with 15 kGy absorbed dose and from 20% to 80% of xylene with 15 kGy absorbed dose in similar concentrations. (author)

  20. Real-time monitoring of benzene, toluene, and p-xylene in a photoreaction chamber with a tunable mid-infrared laser and ultraviolet differential optical absorption spectroscopy.

    Science.gov (United States)

    Parsons, Matthew T; Sydoryk, Ihor; Lim, Alan; McIntyre, Thomas J; Tulip, John; Jäger, Wolfgang; McDonald, Karen

    2011-02-01

    We describe the implementation of a mid-infrared laser-based trace gas sensor with a photoreaction chamber, used for reproducing chemical transformations of benzene, toluene, and p-xylene (BTX) gases that may occur in the atmosphere. The system performance was assessed in the presence of photoreaction products including aerosol particles. A mid-infrared external cavity quantum cascade laser (EC-QCL)-tunable from 9.41-9.88 μm (1012-1063 cm(-1))-was used to monitor gas phase concentrations of BTX simultaneously and in real time during chemical processing of these compounds with hydroxyl radicals in a photoreaction chamber. Results are compared to concurrent measurements using ultraviolet differential optical absorption spectroscopy (UV DOAS). The EC-QCL based system provides quantitation limits of approximately 200, 200, and 600 parts in 10(9) (ppb) for benzene, toluene, and p-xylene, respectively, which represents a significant improvement over our previous work with this laser system. Correspondingly, we observe the best agreement between the EC-QCL measurements and the UV DOAS measurements with benzene, followed by toluene, then p-xylene. Although BTX gas-detection limits are not as low for the EC-QCL system as for UV DOAS, an unidentified by-product of the photoreactions was observed with the EC-QCL, but not with the UV DOAS system.

  1. The investigation of exposure to benzene, toluene, ethylbenzene and xylene (BTEX with Solid Phase Microextr action Method in gas station in Yazd province

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Mosaddegh Mehrjerdi

    2014-01-01

    Full Text Available Abstract Background: Benzene, toluene, ethylbenzene and xylene (BTEX are volatile organic compounds which their physical and chemical characteristics are similar. Evaporation of BTEX from gasoline in petrol station into the air causes gasoline station attendants expose to them. A new extraction method of volatile organic compounds is solid phase microextraction (SPME. The aim of this study is to optimize extraction conditions of BTEX from air samples and then determination of gasoline station air contamination with BTEX in Yazd. Material and Methods: In this study air samples were collected using Tedlar bags and then extracted and analyzed with SPME fiber and gas chromatography equipped with a flame ionization detector. Results: Our results indicate that PDMS/CAR has the best peak area in comparison with two other fibers The Optimized extraction and desorption times are estimated 3 and 1 minutes, respectively Mean concentration of benzene, toluene, ethyl benzene and xylene in gas station’s air were 1932±807, 667±405, 148±89, 340±216 µg/m3 respectively. Conclusion: Benzene mean concentration is above threshold limit value (0.5PPM. Whereas, toluene, ethylbenzene and xylene mean concentration are lower than threshold limit values.

  2. Side chain alkylation of toluene with methanol over basic zeolites - novel production route towards styrene?

    NARCIS (Netherlands)

    Rep, M.; Rep, M.

    2002-01-01

    Styrene is an important monomer for the production of different types of (co-) polymers that are used in, e.g., toys, medical devices, food packaging, paper coatings etc. Styrene is produced with several different industrial processes. In 1998, the production of styrene monomer was approximately 21

  3. The aromatic volatile organic compounds toluene, benzene and styrene induce COX-2 and prostaglandins in human lung epithelial cells via oxidative stress and p38 MAPK activation.

    Science.gov (United States)

    Mögel, Iljana; Baumann, Sven; Böhme, Alexander; Kohajda, Tibor; von Bergen, Martin; Simon, Jan-Christoph; Lehmann, Irina

    2011-10-28

    Toluene, benzene and styrene are volatile organic compounds (VOCs) widely distributed in the environment. Tobacco smoke, traffic exposure and solvents used for paints, rubber and adhesives are known sources for these compounds. The aim of the present study was to investigate whether toluene, benzene and styrene can induce inflammatory reactions in lung cells and to characterize possible underlying mechanisms. A previous study gave evidence that expression of cyclooxygenase-2 (COX-2) is upregulated following exposure to the aromatic VOC chlorobenzene. Here, we investigated the effects of the aromatics toluene, benzene and styrene on human lung cells, with emphasis on COX-2, the rate-limiting enzyme of the prostaglandin pathway. In addition, we studied the potential role of oxidative stress and p38 MAPK activation in the toluene/benzene/styrene-dependent COX-2 induction. Following exposure to the aromatic compounds the expression level of COX-2 increased markedly. In addition, prostaglandin E(2) (PGE(2)) and prostaglandin F(2α) (PGF(2α)), major products of the COX enzyme, were found to be upregulated in response to toluene, benzene or styrene exposure. Furthermore, we observed an activation of p38 MAPK resulting from aromatic VOC exposure. Treatment of the cells with a specific p38 inhibitor (SB203580) or the antioxidant N-acetylcysteine (NAC) was able to prevent the toluene/benzene/styrene-dependent COX-2 activation, and subsequent increased PGE(2) and PGF(2α) secretion. These results suggest that toluene, benzene and styrene induce production and secretion of PGE(2) and PGF(2α) in lung epithelial cells via p38 MAPK and COX-2 activation in a redox sensitive manner. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  4. Optimization of an automated FI-FT-IR procedure for the determination of o-xylene, toluene and ethyl benzene in n-hexane

    OpenAIRE

    Wells, Ian; Worsfold, Paul J.

    1999-01-01

    The development and optimization of an automated flow injection (FI) manifold coupled with a Fourier transform infrared (FT-IR) detector for the determination of toluene, ethyl benzene and o-oxylene in an n-hexane matrix is described. FT-IR parameters optimized were resolution and number of co-added scans; FI parameters optimized were type of pump tubing, carrier flow rate and sample volume. ATR and transmission flow cells were compared for the determination of o-xylene, the ATR cell was easi...

  5. Relative contributions of secondary organic aerosol formation from toluene, xylenes, isoprene, and monoterpenes in Hong Kong and Guangzhou in the Pearl River Delta, China: an emission-based box modeling study

    Science.gov (United States)

    Wang, Siyuan; Wu, Dongwei; Wang, Xin-Ming; Fung, Jimmy Chi-Hung; Yu, Jian Zhen

    2013-01-01

    Secondary organic aerosols (SOA) formed from common anthropogenic and biogenic volatile organic compounds (VOCs) account for a significant portion of organic particulate matter in the ambient atmosphere. The Pearl River Delta (PRD) in southern China, located in the subtropics and as a region with intensive manufacturing industries, has significant emissions of both anthropogenic and biogenic VOCs. Two recent SOA tracer-based measurement studies, one in Hong Kong (located at the mouth of the PRD) and the other at a site 20 to 50 km downwind of urban Guangzhou districts in the middle of the PRD, show a rather considerable difference in the relative SOA contributions from one group of two biogenic VOCs (isoprene and monoterpenes) and one group of anthropogenic VOCs, namely, toluene + xylenes. In Hong Kong, more SOA was formed from isoprene and monoterpenes than from toluene and xylenes, although the relative contributions of the two groups of VOCs were reversed at the site downwind of Guangzhou. An emission-based 0-D box model has been developed to investigate this issue. The emission inputs of major inorganic pollutants and VOCs are generated using the programs Sparse Matrix Operator Kernel Emissions and Model of Emissions of Gases and Aerosols from Nature for this region. Toluene/xylene emissions in Guangzhou are more than twice that in Hong Kong whereas isoprene and monoterpenes emissions were similar at the two locations. The model incorporates a CB05 chemical mechanism and gas-particle partitioning of condensable VOC oxidation products to simulate SOA formation from major VOCs including isoprene, monoterpenes, toluene, and xylenes. The model-simulated VOCs fall within the range of ambient observations, demonstrating reasonable representation of emissions and oxidation of VOCs. The model simulates the sum of the SOA formation from isoprene, monoterpenes, and toluene + xylenes. In Hong Kong, monoterpenes are the major contributor (up to 70%), followed by isoprene

  6. Effect of substrate interaction on the degradation of methyl tert-butyl ether, benzene, toluene, ethylbenzene, and xylene by Rhodococcus sp.

    Science.gov (United States)

    Lee, Eun-Hee; Cho, Kyung-Suk

    2009-08-15

    It was examined the substrate interactions of benzene (B), tolulene (T), ethylbenzene (E), xylene (X), and methyl tert-butyl ether (M) in binary, ternary, quaternary, and quinary mixtures by Rhodococcus sp. EH831 that could aerobically degrade all of five single components. The specific degradation rates (SDRs) of B, T, E, X, and M were 234, 913, 131, 184 and 139 micromol g-dry cell weight (DCW)(-1)h(-1), respectively. In binary, ternary, quaternary, and quinary mixtures of them, ethylbenzene was the strongest inhibitor for the other substrates, and methyl tert-butyl ether was the weakest inhibitor. Interestingly, no degradation of benzene and methyl tert-butyl ether was found in the coexistence of ethylbenzene. The degradation of benzene followed only after toluene became exhausted when both was present. Ethylbenzene was least inhibited by methyl tert-butyl ether and most inhibited by toluene.

  7. The effect of gallium supported on mesoporous silica and its catalytic activity for oxidation of benzene, toluene and o-xylene

    Energy Technology Data Exchange (ETDEWEB)

    Schwanke, A.J.; Pergher, S.; Probst, L.F.D. [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil); Balzer, R. [Universidade Federal do Parana (UFPR), PR (Brazil)

    2016-07-01

    Full text: Benzene, toluene and xylene (BTX) are a particular class of volatile organic compounds, which are highly toxic pollutants. In this study, samples of gallium-containing mesoporous silica (MS-Ga7% and MS-Ga11%) were synthesized and their catalytic activity in the oxidation of BTX was investigated. The physicochemical characterization by XRD, XPS, XRF, nitrogen adsorption and desorption isotherms at 77K, FTIR, SEM and TEM shows that the inclusion of gallium in the mesoporous silica structure leads to an increase in the number of oxygen vacancies in the structure of the MS-Ga system, which can result in an increase in the total and surface oxygen mobility. The results show the highest conversion for benzene (65%), with >40% for toluene and >28% for o-xylene. The high catalytic activity observed was attributed to a combination of several factors including a higher number of active sites (gallium and gallium oxide) being exposed, with a greater mobility of the active oxygen species on the surface of the catalyst promoting the catalytic activity. (author)

  8. Poly(o-anisidine)/graphene oxide nanosheets composite as a coating for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene and xylenes.

    Science.gov (United States)

    Behzadi, Mansoureh; Mirzaei, Mohammad

    2016-04-22

    A poly(o-anisidine)/graphene oxide nanosheets (PoA/GONSs) coating is fabricated by a simple and efficient electrochemical deposition method on steel wire. The incorporation of PoA and GONSs allows preparing a nanocomposite that can successfully integrate the advantages of both. Then, the prepared fiber is applied to the headspace solid-phase microextraction (HS-SPME) and gas chromatographic analysis of benzene, toluene, ethylbenzene and xylenes. In order to obtain an adherent, stable and efficient fiber to extract target analytes, experimental parameters related to the coating process such as deposition potential, deposition time, concentration of the monomer and concentration of GONSs were studied. The prepared composite fiber were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction and scanning electron microscopy. The effect of various parameters on the efficiency of HS-SPME process consisting of desorption temperature and time, extraction temperature and time and ionic strength were also optimized. Under the optimal conditions, the method was linear for orders of magnitude with correlation coefficients varying from 0.9888 to 0.9993. Intra- and inter-day precisions of the method were determined from mixed aqueous solutions containing 5.0 ng mL(-1) of each BTEX. The intra-day precisions varied from 3.1% for toluene to 5.7% for ethylbenzene, while the inter-day precisions varied from 4.9% for o-xylene to 7.3% for m,p-xylene. Limits of detection were in the range 0.01-0.06 ng mL(-1). The proposed method was applied to monitor BTEX compounds in some water samples and the accuracies found through spiking river water samples showed high recoveries between 92.0 and 101.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. The role of substrate binding pocket residues phenylalanine 176 and phenylalanine 196 on Pseudomonas sp. OX1 toluene o-xylene monooxygenase activity and regiospecificity.

    Science.gov (United States)

    Sönmez, Burcu; Yanık-Yıldırım, K Cansu; Wood, Thomas K; Vardar-Schara, Gönül

    2014-08-01

    Saturation mutagenesis was used to generate eleven substitutions of toluene-o-xylene monooxygenase (ToMO) at alpha subunit (TouA) positions F176 and F196 among which nine were novel: F176H, F176N, F176S, F176T, F196A, F196L, F196T, F196Y, F196H, F196I, and F196V. By testing the substrates phenol, toluene, and naphthalene, these positions were found to influence ToMO oxidation activity and regiospecificity. Specifically, TouA variant F176H was identified that had 4.7-, 4.3-, and 1.8-fold faster hydroxylation activity towards phenol, toluene, and naphthalene, respectively, compared to native ToMO. The F176H variant also produced the novel product hydroquinone (61%) from phenol, made twofold more 2-naphthol from naphthalene (34% vs. 16% by the wild-type ToMO), and had the regiospecificity of toluene changed from 51% to 73% p-cresol. The TouA F176N variant had the most para-hydroxylation capability, forming p-cresol (92%) from toluene and hydroquinone (82%) from phenol as the major product, whereas native ToMO formed 30% o-cresol, 19% m-cresol, and 51% of p-cresol from toluene and 100% catechol from phenol. For naphthalene oxidation, TouA variant F176S exhibited the largest shift in the product distribution by producing threefold more 2-naphthol. Among the other F196 variants, F196L produced catechol from phenol two times faster than the wild-type enzyme. The TouA F196I variant produced twofold less o-cresol and 19% more p-cresol from toluene, and the TouA F196A variant produced 62% more 2-naphthol from naphthalene compared to wild-type ToMO. Both of these positions have never been studied through the saturation mutagenesis and some of the best substitutions uncovered here have never been predicted and characterized for aromatics hydroxylation. © 2014 Wiley Periodicals, Inc.

  10. Experimental study and kinetic modeling of the thermal degradation of aromatic volatile organic compounds (benzene, toluene and xylene-para) in methane flames; Etude experimentale et modelisation cinetique de la degradation thermique des composes organiques volatils aromatiques benzenes, toluene et para-xylene dans des flammes de methane

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, L.

    2001-02-01

    This study treats of the thermal degradation of a family of aromatic volatile organic compounds (VOCs) in laminar premixed methane flames at low pressure. The experimental influence of benzene, toluene and xylene-para on the structure of a reference methane flame has been studied. The molar fraction profiles of the stable and reactive, aliphatic, aromatic and cyclic species have been established by the coupling of the molecular beam sampling/mass spectroscopy technique with the gas chromatography/mass spectroscopy technique. Temperature profiles have been measured using a covered thermocouple. A detailed kinetic mechanism of oxidation of these compounds in flame conditions has been developed. Different available sub-mechanisms have been used as references: the GDF-Kin 1.0 model for the oxidation of methane and the models of Tan and Franck (1996) and of Lindstedt and Maurice (1996) in the case of benzene and toluene. In the case of para-xylene, a model has been developed because no mechanisms was available in the literature. These different mechanisms have been refined, completed or adjusted by comparing the experimental results with those obtained by kinetic modeling. The complete kinetic mechanism, comprising 156 chemical species involved in 1072 reactions allows to reproduce all the experimental observations in a satisfactory manner. The kinetic analysis of reactions velocity has permitted to determine oxidation kinetic schemes for benzene, toluene, xylene-para and for the cyclopentadienyl radical, main species at the origin of the rupture of the aromatic cycle. Reactions of recombination with the methyl radicals formed during methane oxidation, of the different aromatic or aliphatic radicals created during the oxidation of aromatics, play an important role and lead to the formation of several aromatic pollutants (ethyl-benzene for instance) or aliphatic pollutants (butadiene or penta-diene for instance) in flames. (J.S.)

  11. Modified dispersive liquid-liquid microextraction for pre-concentration of benzene, toluene, ethylbenzene and xylenes prior to their determination by GC

    International Nuclear Information System (INIS)

    Faraji, Hakim; Feizbakhsh, Alireza; Helalizadeh, Masoumeh

    2013-01-01

    We have developed a modified method for the extraction and preconcentration of benzene, toluene, ethylbenzene and xylenes (BTEX) in aqueous samples. It based on dispersive liquid-liquid microextraction along with solidification of floating organic microdrops. The dispersion of microvolumes of an extracting solvent into the aqueous occurs without dispersive solvent. Various parameters have been optimized. BTEX were quantified via GC with FID detection. Under optimized conditions, the preconcentration factors range from 301 to 514, extraction efficiencies from 60 to 103 %, repeatabilities from 2.2 to 4.1 %, and intermediate precisions from 3.5 to 7.0 %. The relative recovery for each analyte in water samples at three spiking levels is >85.6 %, with a relative standard deviation of <7.4 %. (author)

  12. Variation of isomer distribution in electrophilic nitration of toluene, anisole, and o-xylene: Independence of high regioselectivity from reactivity of reagent*

    Science.gov (United States)

    Olah, George A.; Lin, Henry C.; Olah, Judith A.; Narang, Subhash C.

    1978-01-01

    The nitration of toluene and anisole was studied with nitrating systems of varying reactivity. High regioselectivity of ortho-para over meta substitution was maintained in all nitrations, regardless of the reactivity of the nitrating system. At the same time, the amount of meta substitution stayed low (3% or less), even when the fast reactions may have reached the encounter-controlled limit. Because the nitration of o-xylene, in which both ring positions are activated by the effect of a methyl group, also does not show any diminishing of regioselectivity, the possibility of a dual mechanistic pathway, in which the activated position would react by a fast, encounter-controlled path, whereas the nonactivated meta position by a slower σ-type path, can be ruled out. The data unambiguously prove that the high regioselectivity of electrophilic aromatic nitration is independent of the reactivity of the reagent, because no significant increase of meta substitution of toluene or anisole was observed, regardless of the activity of the nitrating system. No selectivity-reactivity relationship is thus evident and the ortho-para directing effect of primary substituents over meta substitution is always maintained. The variation in the amount of the meta isomer, up to the observed limit of about 3% in the case of toluene and nitrations. Steric factors, such as increasing bulkiness of the nitrating agent, also can affect the ortho-para isomer ratios but are not considered to be the only reason for the observed variations, which reflect the specific nitrating systems, affecting the nature and position of the transition state of highest energy on the reaction pathway. PMID:16592489

  13. -Styrene)

    KAUST Repository

    Sutisna, Burhannudin

    2017-10-04

    Membranes are prepared by self-assembly and casting of 5 and 13 wt% poly(styrene-b-butadiene-b-styrene) (PS-b-PB-b-PS) copolymers solutions in different solvents, followed by immersion in water or ethanol. By controlling the solution-casting gap, porous films of 50 and 1 µm thickness are obtained. A gradient of increasing pore size is generated as the distance from the surface increased. An ordered porous surface layer with continuous nanochannels can be observed. Its formation is investigated, by using time-resolved grazing incident small angle X-ray scattering, electron microscopy, and rheology, suggesting a strong effect of the air-solution interface on the morphology formation. The thin PS-b-PB-b-PS ordered films are modified, by promoting the photolytic addition of thioglycolic acid to the polybutadiene groups, adding chemical functionality and specific transport characteristics on the preformed nanochannels, without sacrificing the membrane morphology. Photomodification increases fivefold the water permeance to around 2 L m(-2) h(-1) bar(-1) , compared to that of the unmodified one. A rejection of 74% is measured for methyl orange in water. The membranes fabrication with tailored nanochannels and chemical functionalities can be demonstrated using relatively lower cost block copolymers. Casting on porous polyacrylonitrile supports makes the membranes even more scalable and competitive in large scale.

  14. Removal of o-xylene using biofilter inoculated with Rhodococcus sp. BTO62.

    Science.gov (United States)

    Jeong, Euisoon; Hirai, Mitsuyo; Shoda, Makoto

    2008-03-21

    Rhodococcus sp. BTO62 was isolated from activated sludge from a wastewater treatment plant as an o-xylene-degrading microorganism. BOT62 degraded not only o-xylene, but also benzene, toluene, ethylbenzene, m- and p-xylenes and styrene (BTEXS). A laboratory scale biofilter packed with Biosol as packing material, which is made from foamed waste glass mixed with corrugated cardboard, was inoculated with strain BTO62 and operated to remove relatively high loading of o-xylene at different space velocities under non-sterile and sterile conditions. The o-xylene elimination capacity to maintain more than 90% removal efficiency was 41g/m3/h under sterile condition, but it enhanced to 160g/m3/h under non-sterile condition. This indicates possibilities of the role of other contaminants for degradation of o-xylene and the degradation of intermediate products of o-xylene by contaminants. Quick recovery of o-xylene degradation was observed after shutdown of o-xylene gas supply and mineral medium circulation for 10-30 days.

  15. Testicular atrophy and loss of nerve growth factor-immunoreactive germ cell line in rats exposed to n-hexane and a protective effect of simultaneous exposure to toluene or xylene

    Energy Technology Data Exchange (ETDEWEB)

    Nylen, P.; Johnson, A.C.; Hoeglund, G.; Ebendal, T.; Eriksdotter-Nilsson, M.; Henschen, A.; Olson, L.; Hansson, T.; Kronevi, T.; Kvist, U.

    1989-07-01

    Testicular and germ cell line morphology in rats were studied 2 weeks, 10 months and 14 months after cessation of a 61-day inhalation exposure to 1000 ppm n-hexane. Androgen biosynthetic capacity of testis, testosterone blood concentration, vas deferens morphology and noradrenaline (NA) concentration, epididymal sperm morphology, and fertility were also studied. Severe testicular atrophy involving the seminiferous tubules with loss of the nerve growth factor (NGF) immunoreactive germ cell line was found. Total loss of the germ cell line was found in a fraction of animals up to 14 months post-exposure, indicating permanent testicular damage. No impairment of androgen synthesis or androgen dependent accessory organs was observed. Simultaneous administration of 1000 ppm n-hexane and 1000 ppm toluene, or 1000 ppm n-hexane and 1000 ppm xylene, did not cause germ cell line alterations or testicular atrophy. Toluene and xylene were thus found to protect from n-hexane induced testicular atrophy. (orig.).

  16. Biodegradation of BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) composites present in the petrochemical effluents industries; Biodegradacao dos compostos BTX (Benzeno, Tolueno e Xilenos) presentes em efluentes petroquimicos

    Energy Technology Data Exchange (ETDEWEB)

    Minatti, Gheise; Mello, Josiane M.M. de; Souza, Selene M.A. Guelli Ulson de; Antonio Augusto Ulson de [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2008-07-01

    The compounds BTX inside of the petrochemical effluent have presented a high potential of pollution, representing a serious risk to the environment and to the human. The great improvements in the field of biological treatment of liquid effluent were reached through the process using biofilm capable of degrading toxic compounds. The objective of this paper is to determine the degradation kinetics of BTX using biofilm. The experimental data were compared with two kinetic models, kinetic of first order and model of Michaelis-Menten. The kinetic parameters of BTX compounds were experimentally obtained in a bioreactor in batch with biomass immobilized in activated-carbon, being fed daily with solution of nutrients and BTX. For the kinetic models studied in this paper, the best performance was achieved with the model of Michaelis-Menten showing a good correlation coefficient for the three compounds. The biomass amount in these bioreactors was 49.18, 28.35 and 5.15 mg of SSV per gram of support for the toluene, benzene and o-xylene, respectively. The experimental tests showed that the biomass inside of bioreactor is capable to degrade all compounds in a time of approximately 300 minutes. (author)

  17. The active and passive sampling of benzene, toluene, ethyl benzene and xylenes compounds using the inside needle capillary adsorption trap device.

    Science.gov (United States)

    Shojania, S; Oleschuk, R D; McComb, M E; Gesser, H D; Chow, A

    1999-08-23

    A new and simple method of solventless extraction of volatile organic compounds (VOCs) from air is presented. The sampling device has an adsorbing carbon coating on the interior surface of a hollow needle, and is called the inside needle capillary adsorption trap (INCAT). This paper describes a study of the reproducibility in the preparation and sampling of the INCAT device. In addition, this paper examines the effects of sample volume in active sampling and exposure time in passive sampling on the analyte adsorption. Analysis was achieved by sampling the air from an environmental chamber doped with benzene, toluene, ethyl benzene and xylenes (BTEX) compounds. Initial rates of adsorption were found to vary among the different compounds, but ranged from 0.0099 to 0.016 nmol h(-1) for passive sampling and from 2.2 to 10 nmol h(-1) for active sampling. Analysis was done by thermal desorption of the adsorbed compounds directly into a gas chromatograph injection port. Quantification of the analysis was done by comparison to actively sampled activated carbon solid phase extraction (SPE) measurements.

  18. Optimization of non-thermal plasma efficiency in the simultaneous elimination of benzene, toluene, ethyl-benzene, and xylene from polluted airstreams using response surface methodology.

    Science.gov (United States)

    Najafpoor, Ali Asghar; Jonidi Jafari, Ahmad; Hosseinzadeh, Ahmad; Khani Jazani, Reza; Bargozin, Hasan

    2018-01-01

    Treatment with a non-thermal plasma (NTP) is a new and effective technology applied recently for conversion of gases for air pollution control. This research was initiated to optimize the efficient application of the NTP process in benzene, toluene, ethyl-benzene, and xylene (BTEX) removal. The effects of four variables including temperature, initial BTEX concentration, voltage, and flow rate on the BTEX elimination efficiency were investigated using response surface methodology (RSM). The constructed model was evaluated by analysis of variance (ANOVA). The model goodness-of-fit and statistical significance was assessed using determination coefficients (R 2 and R 2 adj ) and the F-test. The results revealed that the R 2 proportion was greater than 0.96 for BTEX removal efficiency. The statistical analysis demonstrated that the BTEX removal efficiency was significantly correlated with the temperature, BTEX concentration, voltage, and flow rate. Voltage was the most influential variable affecting the dependent variable as it exerted a significant effect (p polluted with BTEX in conditions of low residence time and high concentrations of pollutants.

  19. (Liquid + liquid) equilibria of ternary and quaternary systems containing n-hexane, toluene, m-xylene, propanol, sulfolane, and water at T = 303.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Mohsen-Nia, M. [Thermodynamic Research Lab, Department of Chemical Engineering, Kashan University, Ghotbe Ravandi, Kashan 87317-51167 (Iran, Islamic Republic of)]. E-mail: m.mohsennia@kashanu.ac.ir; Paikar, I. [Thermodynamic Research Lab, Department of Chemical Engineering, Kashan University, Ghotbe Ravandi, Kashan 87317-51167 (Iran, Islamic Republic of)

    2007-07-15

    (Liquid + liquid) equilibrium data for ternary and quaternary systems containing n-hexane (C{sub 6}H{sub 14}), toluene (C{sub 7}H{sub 8}), m-xylene (C{sub 8}H{sub 10}), propanol (C{sub 3}H{sub 8}O), sulfolane (C{sub 4}H{sub 8}SO{sub 2}), and water (H{sub 2}O) were measured at T = 303.15 K. Phase diagrams of {l_brace}w {sub 1}C{sub 4}H{sub 8}SO{sub 2} + w {sub 2}C{sub 7}H{sub 8} + (1 - w {sub 1} - w {sub 2})C{sub 6}H{sub 14}{r_brace}, {l_brace}w {sub 1}C{sub 4}H{sub 8}SO{sub 2} + w {sub 2}C{sub 8}H{sub 10} + (1 - w {sub 1} - w {sub 2})C{sub 6}H{sub 14}{r_brace}, {l_brace}w {sub 1}C{sub 4}H{sub 8}SO{sub 2} + w {sub 2}C{sub 3}H{sub 8}O + w {sub 3}C{sub 7}H{sub 8} + (1 - w {sub 1} - w {sub 2} - w {sub 3})C{sub 6}H{sub 14}{r_brace} and also systems containing water: {l_brace}w {sub 1}C{sub 4}H{sub 8}SO{sub 2} + w {sub 2}H{sub 2}O + w {sub 3}C{sub 7}H{sub 8} + (1 - w {sub 1} - w {sub 2} - w {sub 3})C{sub 6}H{sub 14}{r_brace} and {l_brace}w {sub 1}C{sub 4}H{sub 8}SO{sub 2} + w {sub 2}H{sub 2}O + w {sub 3}C{sub 8}H{sub 10} + (1 - w {sub 1} - w {sub 2} - w {sub 3})C{sub 6}H{sub 14}{r_brace} (w = mass fraction) were obtained at T 303.15 K. The (liquid + liquid) equilibrium data of the systems were used to obtain interaction parameters in non-random two-liquid (NRTL) and universal quasi-chemical theory (UNIQUAC) activity coefficient models. These parameters can be used to predict equilibrium data of ternary and quaternary systems. The root mean square deviations (RMSDs) using these models were calculated and reported. The partition coefficients and the selectivity factors of solvents for extraction of toluene or m-xylene from n-hexane at T = 303.15 K are calculated and presented. The experimental selectivity factors of sulfolane for the system {l_brace}w {sub 1}C{sub 4}H{sub 8}SO{sub 2} + w {sub 2}C{sub 7}H{sub 8} + (1 - w {sub 1} - w {sub 2})C{sub 6}H{sub 14}{r_brace} at T = 298.15 K and T = 323.15 K were taken from the literature and the influence of temperature on the

  20. Evaluating the effects of maternal exposure to benzene, toluene, ethyl benzene, and xylene on oral clefts among offspring in Texas: 1999-2008.

    Science.gov (United States)

    Ramakrishnan, Anushuya; Lupo, Philip J; Agopian, A J; Linder, Stephen H; Stock, Thomas H; Langlois, Peter H; Craft, Elena

    2013-08-01

    There is evidence from previous studies that maternal occupational exposure to hazardous air pollutants (HAPs) is positively associated with oral clefts; however, studies evaluating the association between residential exposure to these toxicants and oral clefts are lacking. Therefore, our goal was to conduct a case-control study examining the association between estimated maternal residential exposure to benzene, toluene, ethyl benzene, and xylene (BTEX) and the risk of oral clefts among offspring. Data on 6045 nonsyndromic isolated oral cleft cases (3915 cleft lip with or without cleft palate [CL ± P] and 2130 nonsyndromic isolated cleft palate [CP] cases) delivered between 1999 and 2008 were obtained from the Texas Birth Defects Registry. The control group was a sample of unaffected live births, frequency matched to cases on year of birth. Census tract-level estimates of annual average exposures were obtained from the U.S. Environmental Protection Agency 2005 Hazardous Air Pollutant Exposure Model (HAPEM5) for each pollutant and assigned to each subject based on maternal residence during pregnancy. Logistic regression was used to assess the relationship between estimated maternal exposure to each pollutant (BTEX) separately and the risk of oral clefts in offspring. High estimated maternal exposure to benzene was not associated with oral clefts, compared with low estimated exposure (CL ± P adjusted OR = 0.95; 95% CI = 0.81 - 1.12; CP adjusted OR = 0.85; 95% CI = 0.67 - 1.09). Similar results were seen for the other pollutants. In our study, there was no evidence that maternal exposure to environmental levels of BTEX was associated with oral clefts. Copyright © 2013 Wiley Periodicals, Inc.

  1. Evaluation of potential toxicity from co-exposure to three CNS depressants (toluene, ethylbenzene, and xylene) under resting and working conditions using PBPK modeling.

    Science.gov (United States)

    Dennison, James E; Bigelow, Philip L; Mumtaz, Moiz M; Andersen, Melvin E; Dobrev, Ivan D; Yang, Raymond S H

    2005-03-01

    Under OSHA and American Conference of Governmental Industrial Hygienists (ACGIH) guidelines, the mixture formula (unity calculation) provides a method for evaluating exposures to mixtures of chemicals that cause similar toxicities. According to the formula, if exposures are reduced in proportion to the number of chemicals and their respective exposure limits, the overall exposure is acceptable. This approach assumes that responses are additive, which is not the case when pharmacokinetic interactions occur. To determine the validity of the additivity assumption, we performed unity calculations for a variety of exposures to toluene, ethylbenzene, and/or xylene using the concentration of each chemical in blood in the calculation instead of the inhaled concentration. The blood concentrations were predicted using a validated physiologically based pharmacokinetic (PBPK) model to allow exploration of a variety of exposure scenarios. In addition, the Occupational Safety and Health Administration and ACGIH occupational exposure limits were largely based on studies of humans or animals that were resting during exposure. The PBPK model was also used to determine the increased concentration of chemicals in the blood when employees were exercising or performing manual work. At rest, a modest overexposure occurs due to pharmacokinetic interactions when exposure is equal to levels where a unity calculation is 1.0 based on threshold limit values (TLVs). Under work load, however, internal exposure was 87%higher than provided by the TLVs. When exposures were controlled by a unity calculation based on permissible exposure limits (PELs), internal exposure was 2.9 and 4.6 times the exposures at the TLVs at rest and workload, respectively. If exposure was equal to PELs outright, internal exposure was 12.5 and 16 times the exposure at the TLVs at rest and workload, respectively. These analyses indicate the importance of (1) selecting appropriate exposure limits, (2) performing unity

  2. Cobalt oxide nanoparticles as a novel high-efficiency fiber coating for solid phase microextraction of benzene, toluene, ethylbenzene and xylene from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gholivand, Mohammad Bagher, E-mail: MB.Gholivand@yahoo.com [Department of Analytical Chemistry, Faculty of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Shamsipur, Mojtaba; Shamizadeh, Mohammad [Department of Analytical Chemistry, Faculty of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Moradian, Rostam; Astinchap, Bandar [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Nano Technology Research Laboratory, Razi University, Kermanshah (Iran, Islamic Republic of)

    2014-04-01

    Highlights: • Co{sub 3}O{sub 4} nanoparticles were introduced as a novel SPME fiber coating. • The fiber was evaluated for the extraction of BTEX in combination with GC–MS. • The fiber showed extraction efficiencies better than a PDMS fiber toward BTEX. • The fiber was successfully applied to the determination of BTEX in real samples. - Abstract: In this work cobalt oxide nanoparticles were introduced for preparation of a novel solid phase microextraction (SPME) fiber coating. Chemical bath deposition (CBD) technique was used in order for synthesis and immobilization of the Co{sub 3}O{sub 4} nanomaterials on a Pt wire for fabrication of SPME fiber. The prepared cobalt oxide coating was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The fiber was evaluated for the extraction of benzene, toluene, ethylbenzene and xylene (BTEX) in combination with GC–MS. A simplex optimization method was used to optimize the factors affecting the extraction efficiency. Under optimized conditions, the proposed fiber showed extraction efficiencies comparable to those of a commercial polydimethylsiloxane (PDMS) fiber toward the BTEX compounds. The repeatability of the fiber and its reproducibility, expressed as relative standard deviation (RSD), were lower than about 11%. No significant change was observed in the extraction efficiency of the new SPME fiber after over 50 extractions. The fiber was successfully applied to the determination of BTEX compounds in real samples. The proposed nanostructure cobalt oxide fiber is a promising alternative to the commercial fibers as it is robust, inexpensive and easily prepared.

  3. Measurement of BTEX (benzene, toluene, ethybenzene, and xylene) levels at urban and semirural areas of Algiers City using passive air samplers.

    Science.gov (United States)

    Kerchich, Yacine; Kerbachi, Rabah

    2012-12-01

    The study presents the levels of air pollution by aromatic organic compounds BTEX (benzene, toluene, ethylbenzene, o-, m-, and p-xylenes) in the city of Algiers. The sampling was carried out using Radiello passive sampler. Three sampling campaigns were carried out in roadside, tunnel, urban background, and semirural sites in Algiers. In order to determine the diurnal mean levels of air pollution by BTEX to which people are exposed, a modified passive sampler was used for the first time. In addition, monitoring of pollution inside vehicles was also made. In the spring of 2009, more than 27 samplings were carried out. In the background and road traffic sites the Radiello sampler was exposed for 7 days, whereas the time exposure was reduced to 1 day in the case of the vehicle as well as the tunnel. The results indicate that average benzene concentrations in the roadside and inside vehicle exceed largely the limit value of 5 microg m(-3) established by the European Community (EC). On the other hand, it has been noticed that the concentration levels of other BTEX are relatively high. Also, in order to identify the origin of emission sources, ratios and correlations between the BTEX species have been highlighted. This study shows that road traffic remains the main source of many local emission in Algiers. The vehicle fleet in Algeria is growing rapidly since the 1990s following economic growth and is responsible for the increasing air pollution in large cities. Because there are no data collection of BTEX carried out by national air quality network, all environmental and transportation policies are based on European emissions standards, but national emission standards are currently not in place. This work will contribute to the analysis of real emissions of BTEX in Algiers, for the development of management and for assessment of population exposure variation depending on the location in the city of Algiers.

  4. Quantification of benzene, toluene, ethylbenzene and o-xylene in internal combustion engine exhaust with time-weighted average solid phase microextraction and gas chromatography mass spectrometry.

    Science.gov (United States)

    Baimatova, Nassiba; Koziel, Jacek A; Kenessov, Bulat

    2015-05-11

    A new and simple method for benzene, toluene, ethylbenzene and o-xylene (BTEX) quantification in vehicle exhaust was developed based on diffusion-controlled extraction onto a retracted solid-phase microextraction (SPME) fiber coating. The rationale was to develop a method based on existing and proven SPME technology that is feasible for field adaptation in developing countries. Passive sampling with SPME fiber retracted into the needle extracted nearly two orders of magnitude less mass (n) compared with exposed fiber (outside of needle) and sampling was in a time weighted-averaging (TWA) mode. Both the sampling time (t) and fiber retraction depth (Z) were adjusted to quantify a wider range of Cgas. Extraction and quantification is conducted in a non-equilibrium mode. Effects of Cgas, t, Z and T were tested. In addition, contribution of n extracted by metallic surfaces of needle assembly without SPME coating was studied. Effects of sample storage time on n loss was studied. Retracted TWA-SPME extractions followed the theoretical model. Extracted n of BTEX was proportional to Cgas, t, Dg, T and inversely proportional to Z. Method detection limits were 1.8, 2.7, 2.1 and 5.2 mg m(-3) (0.51, 0.83, 0.66 and 1.62 ppm) for BTEX, respectively. The contribution of extraction onto metallic surfaces was reproducible and influenced by Cgas and t and less so by T and by the Z. The new method was applied to measure BTEX in the exhaust gas of a Ford Crown Victoria 1995 and compared with a whole gas and direct injection method. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Benzene, toluene and xylene biodegradation by Pseudomonas putida CCMI 852 Biodegradação de benzeno, tolueno e xileno pela Pseudomonas putida CCMI 852

    Directory of Open Access Journals (Sweden)

    Marcelo Henrique Otenio

    2005-09-01

    Full Text Available A minimal liquid medium containing benzene (B, toluene (T and xylene (X and mixtures thereof, was used to evaluate degradation activity of Pseudomonas putida CCMI 852 containing a TOL plasmid. Experiments were developed with B, T and X (100 mg L-1, with mixtures of BT, BX, and TX (50 + 50 mg L-1 each and BTX (33.3 + 33.3 + 33.3 mg L-1 each, added to 500 mL of medium. After 18 to 24 hours, the inoculum was added and solvent disappearance was determined after 24 to 25 hours by GC. Results showed that P. putida CCMI 852 was able to metabolize T and X, but B was not metabolized. In a BTX mixture, B was not metabolized and T and X degradation rate decreased 50%.Meio mineral líquido contendo benzeno (B ou tolueno (T ou xileno (X a 100 mg L-1 e suas misturas de BT, BX e TX (50 + 50 mg L-1 cada mistura e BTX (33,3 + 33,3 + 33,3 mg L-1 cada mistura foram utilizados para avaliar a atividade de degradação de B, T e X por Pseudomonas putida CCMI 852 contendo um plasmídeo TOL. Após 18 a 24 horas de homogenização da mistura, o inoculo foi adicionado e o decréscimo da concentração dos solventes foi determinado entre 24 e 25 horas por GC. Pseudomonas putida CCMI 852 foi capaz de metabolizar T e X, mas não B. Na mistura BTX, B não foi metabolizado também e a velocidade de degradação de T e X decresceu cerca de 50% comparado com soluções contendo apenas T ou X.

  6. Micro-solid phase extraction of benzene, toluene, ethylbenzene and xylenes from aqueous solutions using water-insoluble β-cyclodextrin polymer as sorbent.

    Science.gov (United States)

    Nojavan, Saeed; Yazdanpanah, Mina

    2017-11-24

    Water-insoluble β-cyclodextrin polymer was synthesized by chemical cross-linking using epichlorohydrin (EPI) as a cross-linker agent. The produced water-insoluble polymer was used as a sorbent for the micro-solid phase extraction (μ-SPE) of benzene, toluene, ethylbenzene and xylenes (BTEX) from water samples. The μ-SPE device consisted of a sealed tea bag envelope containing 15mg of sorbent. For the evaluation of the extraction efficiency, parameters such as extraction and desorption time, desorption solvent and salt concentration were investigated. At an extraction time of 30min in the course of the extraction process, analytes were extracted from a 10mL aqueous sample solution. The analytes were desorbed by ultrasonication in 200μL of acetonitrile for 20min. Analysis of the analytes was done by a gas chromatography-flame ionization detector (GC-FID) system. The enrichment factor (EF) was found to be in the range 23.0-45.4 (EF max =50.0). The method provided linearity ranges of between 0.5 and 500.0ng/mL (depending on the analytes), with good coefficients of determination (r 2 ) ranging between 0.997 and 0.999 under optimized conditions. Detection limits for BTEX were in the range of between 0.15 and 0.60ng/mL, while corresponding recoveries were in the range of 46.0-90.0%. The relative standard deviation of the method for the analytes at 100.0ng/mL concentration level ranged from 5.5 to 11.2% (n=5). The proposed method was concluded to be a cost effective and environmentally-friendly extraction technique with ease of operation and minimal usage of organic solvent. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Xylene isomerization

    KAUST Repository

    Bilaus, Rakan Sulaiman

    2016-06-23

    A process for producing xylenes, in particular para-xylene that is less energy intensive than conventional processes is provided. In an embodiment the process comprises contacting a feed mixture in an isomenzation zone with a catalyst at isomenzation conditions and producing an isomerized product comprising a higher proportion of p-xylene than in the feed mixture, wherein the catalyst comprises an acidic sulfonated catalytic membrane. Xylene isomenzation can also be coupled with a p-xylene extraction process, where the raffinate (p-xylene deprived stream) from the extraction process is fed to an isomenzation reactor to produce p-xylene. In an embodiment, the process can comprise: a) providing a feed stream comprising a mixture of xylene isomers including p-xylene; b) extracting p-xylene from the feed stream using a separator to separate the feed stream into a p-xylene rich stream and a p-xylene deprived stream; and c) delivering the p-xylene deprived stream to an isomenzation unit, the isomenzation unit including an acidic sulfonated catalytic membrane, and using the isomenzation unit to produce an isomerized product comprising a higher proportion of p-xylene than in the p-xylene deprived stream delivered to the isomenzation unit. In any one or more aspects, the isomenzation unit can be operated at a temperature in the range of less than 350°, for example about 20°C to about 200°C.

  8. Iron-functionalized titanium dioxide on flexible glass fibers for photocatalysis of benzene, toluene, ethylbenzene, and o-xylene (BTEX) under visible- or ultraviolet-light irradiation.

    Science.gov (United States)

    Yang, Sung-Bong; Chun, Ho-Hwan; Tayade, Rajesh J; Jo, Wan-Kuen

    2015-03-01

    Iron-functionalized titanium dioxide (TiO2) composites with various Fe-to-Ti ratios were prepared on flexible glass fibers (GF-Fe-TiO2) via a sol-gel method, followed by a dip-coating process. The photocatalytic ability of these composites in degrading selected volatile organic compounds (VOCs; benzene, toluene, ethylbenzene, and o-xylene [BTEX]) at indoor concentration levels was examined. The GF-Fe-TiO2 composites were characterized using scanning electron microscopy, energy-dispersive X-ray elemental analysis, ultraviolet (UV)-visible spectroscopy, and X-ray diffraction. The GF-Fe-TiO2 composites showed superior photocatalytic performance to that of a reference glass fiber-supported TiO2 photocatalyst for the treatment of BTEX under visible light. However, this trend was reversed under UV irradiation. Specifically, the average BTEX photocatalytic efficiencies of the 0.01-GF-Fe-TiO2 composite in a 3-hr visible-light photocatalytic process were 4%, 33%, 51%, and 74%, respectively. Conversely, the average BTEX photocatalytic efficiencies obtained for GF-TiO2 were close to 0%, 5%, 16%, and 29%, respectively. These findings demonstrated that the GF-Fe-TiO2 composites could be applied to photocatalytically purify BTEX, especially under visible-light exposure. Moreover, the GF-Fe-TiO2 composites prepared with different Fe-to-Ti ratios displayed different BTEX photocatalytic decomposition efficiencies under visible or UV light, allowing for optimization of the Fe-to-Ti ratio (which was found to be 0.01). The application of nanomaterials for air purification necessitates a supporting material to stabilize them while in contact with the treated air in the photocatalytic chamber. Glass fibers have an obvious advantage over other supporting materials mainly because of its flexibility, which makes it much easier to handle. However, the applications of glass fiber-supported, visible light-activated photocatalysts to the treatment of air pollutants are rarely reported in

  9. Excess molar volumes of (acetophenone+benzene, or toluene, or 1,3-xylene, or 1,3,5-trimethylbenzene) at temperatures (298.15 and 328.15) K

    International Nuclear Information System (INIS)

    Moravkova, L.; Linek, J.

    2005-01-01

    The densities of (acetophenone+benzene, or toluene, or 1,3-xylene, or 1,3,5-trimethylbenzene) were measured at temperatures (298.15 and 328.15) K by means of a vibrating-tube densimeter. The excess molar volumes V m E calculated from the density data show that the deviations from ideal behaviour in the systems studied (all being negative) become more negative as the temperature is raised. The V m E results were correlated using the fourth-order Redlich-Kister equation, with the maximum likelihood principle being applied for the determination of the adjustable parameters

  10. Excess and deviation properties for the binary mixtures of methylcyclohexane with benzene, toluene, p-xylene, mesitylene, and anisole at T = (298.15, 303.15, and 308.15) K

    International Nuclear Information System (INIS)

    Baragi, Jagadish G.; Aralaguppi, Mrityunjaya I.

    2006-01-01

    Experimental data on density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, while speed of sound values at T = 298.15 K are presented for the binary mixtures of (methylcyclohexane + benzene), methylbenzene (toluene), 1,4-dimethylbenzene (p-xylene), 1,3,5-trimethylbenzene (mesitylene), and methoxybenzene (anisole). From these data of density, viscosity, and refractive index, the excess molar volume, the deviations in viscosity, molar refraction, speed of sound, and isentropic compressibility have been calculated. The computed values have been fitted to Redlich-Kister polynomial equation to derive the coefficients and estimate the standard errors. Variations in the calculated excess quantities for these mixtures have been studied in terms of molecular interactions between the component liquids and the effects of methyl and methoxy group substitution on benzene ring

  11. Excess molar volumes of (octane + benzene, or toluene, or 1,3-xylene, or 1,3,5-trimethylbenzene) at temperatures between (298.15 and 328.15) K

    International Nuclear Information System (INIS)

    Moravkova, L.; Linek, J.

    2008-01-01

    The densities of (octane + benzene, or toluene, or 1,3-xylene, or 1,3,5-trimethylbenzene) were measured at temperatures (298.15, 308.15, 318.15, and 328.15) K by means of a vibrating-tube densimeter. The excess molar volumes V m E calculated from the density data provide the temperature dependence of V m E in the temperature range of (298 to 328) K. The V m E results were correlated using the fourth-order Redlich-Kister equation, with the maximum likelihood principle being applied for the determination of the adjustable parameters. It was found that the values of V m E are not very much dependent on temperature and in all cases decrease with the number of methyl groups on benzene ring of the alkylbenzene

  12. (Liquid + liquid) equilibria of three ternary systems: (heptane + benzene + N-formylmorpholine), (heptane + toluene + N-formylmorpholine), (heptane + xylene + N-formylmorpholine) from T = (298.15 to 353.15) K

    International Nuclear Information System (INIS)

    Chen Dongchu; Ye Hongqi; Wu Hao

    2007-01-01

    (Liquid + liquid) equilibrium (LLE) data for ternary systems: (heptane + benzene + N-formylmorpholine), (heptane + toluene + N-formylmorpholine), and (heptane + xylene + N-formylmorpholine) have been determined experimentally at temperatures ranging from 298.15 K to 353.15 K. Complete phase diagrams were obtained by determining solubility and tie-line data. Tie-line compositions were correlated by Othmer-Tobias and Bachman methods. The universal quasichemical activity coefficient (UNIQUAC) and the non-random two liquids equation (NRTL) were used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data. It is found that UNIQUAC and NRTL used for LLE could provide a good correlation. Distribution coefficients, separation factors, and selectivity were evaluated for the immiscibility region

  13. Determinação de benzeno, tolueno, etilbenzeno e xilenos em gasolina comercializada nos postos do estado do Piauí Determination of benzene, toluene, ethylbenzene and xylenes in commercial gasoline from Piaui state

    Directory of Open Access Journals (Sweden)

    Flamys Lena do N. Silva

    2009-01-01

    Full Text Available Automotive gasoline consists of a complex mixture of flammable and volatile hydrocarbons derived from crude oil with carbon numbers within the range of 4-12 and boiling points range of 30-225 ºC. Its composition varies with the kind of crude oil and the type of refinery process that they undergone. Aromatics hydrocarbons, in particular benzene, toluene, ethylbenzene and isomeric xylenes (BTEX are the toxic group constituents presents. GC-FID was employed to quantify these hydrocarbons in 50 commercial gasoline samples from Piauí state. Statistical analysis techniques, such as PCA and HCA were used to analyze the data. Moreover, several validation parameters were evaluated.

  14. Evaluation of seawater contamination with benzene, toluene and xylene in the Ubatuba north coast, SP region, and study of their removal by ionizing radiation; Avaliacao da contaminacao da agua do mar por benzeno, tolueno e xileno na regiao de Ubatuba, litoral norte (SP) e estudo da degradacao destes compostos por radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Kelly Cristina Santana de

    2006-07-01

    A major concern with leaking petroleum is the environmental contamination by the toxic and low water-soluble components such as benzene, toluene, and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. The objective of this study was to evaluate the contamination of seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene, and xylene, and their removal by the exposure to the ionizing radiation. The studied region was Ubatuba region, SP, between 23 deg 26'S and 23 deg 46'S of latitude and 45 deg 02'W and 45 deg 11'W of longitude, area of carry and output of petroleum, and samples were collected from November, 2003 to July, 2005. For BTX in seawater analysis, the Purge and Trap concentrator with FIDGC detector showed significantly higher sensibility than Head Space concentrator with MSGC detector. The minimal detected limits (MDL) obtained at FIDGC were of 0.50 {mu}g/L for benzene, 0.70 {mu}g/L for toluene, and 1.54 {mu}g/L for xylene, and the obtained experimental variability was 15%. While the concentrator type Headspace system with MS detector showed higher MLD, about of 9.30 mg/L for benzene, 8.50 mg/L for toluene, and 9.80 mg/L for xylene, and 10% of experimental variability. In the studied area the benzene concentration varied from 1.0 {mu}g/L to 2.0 {mu}g/L, the concentration of toluene varied from < 0.70 {mu}g/L to 3.24 {mu}g/L and the maximum value of xylene observed was of 2.92 {mu}g/L. The seawater samples contaminated with BTX standard and exposed to ionizing radiation using a source of {sup 60}Co, presented a removal from 10% to 40% of benzene at 20 kGy absorbed doses and concentration of 35.1 mg/L and 70.2 mg/L, respectively; from 20% to 60% of toluene removal with 15 kGy absorbed dose and from 20% to 80% of xylene with 15 kGy absorbed dose in similar concentrations. (author)

  15. Hollow fiber supported liquid-phase microextraction using ionic liquid as extractant for preconcentration of benzene, toluene, ethylbenzene and xylenes from water sample with gas chromatography-hydrogen flame ionization detection.

    Science.gov (United States)

    Ma, Xiaoguo; Huang, Minghua; Li, Zhihua; Wu, Jianmei

    2011-10-30

    A novel method has been developed for the analysis of benzene, toluene, ethyl-benzene, and o-, m- and p-xylenes (BTEXs) in water using hollow fiber supported liquid-phase microextraction (HF-LPME) followed by gas chromatography-hydrogen flame ionization detection. Ionic liquid 1-butyl-3-methy-limidazolium hexafluorophosphate ([BMIM][PF(6)]) was acted as the extractant for extraction and preconcentration of BTEXs from aqueous samples, and a porous-walled polypropylene hollow fiber was utilized to stabilize and protect [BMIM][PF(6)] during the extraction process. Various parameters that affect extraction efficiency were investigated in detail, and the optimized experimental conditions were as follows: 8 μL of [BMIM][PF(6)] as extraction solvent for the target analytes in 20 mL of sample solution, 30 min of extraction time, a stirring rate of 1400 rpm and 15% NaCl (w/v) in aqueous sample at 25°C (ambient temperature). The recovery was found to be 90.0-111.5% with RSD (n=5) of 1.3-5.4%, and the detection limits (S/N=3) were in the range of 2.7-4.0 μg/L. The proposed method was simple, cheap, rapid, sensitive and environmentally benign, and could act as an alternative to techniques for BTEXs analysis with expensive instrumentations. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Catalytic oxidation of volatile organic compounds (n-hexane, benzene, toluene, o-xylene promoted by cobalt catalysts supported on γ-Al2O3-CeO2

    Directory of Open Access Journals (Sweden)

    R. Balzer

    2014-09-01

    Full Text Available Cobalt catalysts supported on γ-alumina, ceria and γ-alumina-ceria, with 10 or 20%wt of cobalt load, prepared by the wet impregnation method and characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, field emission transmission electron microscopy (FETEM, N2 adsorption-desorption isotherms (BET/BJH methods, energy-dispersive X-ray spectroscopy (EDX, X-ray photoemission spectroscopy (XPS, O2-chemisorption and temperature programmed reduction (TPR were used to promote the oxidation of volatile organic compounds (n-hexane, benzene, toluene and o-xylene. For a range of low temperatures (50-350 °C, the activity of the catalysts with a higher cobalt load (20% wt was greater than that of the catalysts with a lower cobalt load (10% wt. The Co/γ-Al2O3-CeO2 catalytic systems presented the best performances. The results obtained in the characterization suggest that the higher catalytic activity of the Co20/γ-Al2O3-CeO2 catalyst may be attributed to the higher metal content and amount of oxygen vacancies, as well as the effects of the interaction between the cobalt and the alumina and cerium oxides.

  17. Surface grafting of styrene on polypropylene fibers by argon plasma and its adsorption-regeneration of BTX

    Science.gov (United States)

    Xu, J. J.; Guo, M. L.; Chen, Q. G.; Lian, Z. Y.; Wei, W. J.; Luo, Z. W.; Xie, G.; Chen, H. N.; Dong, K.

    2017-08-01

    Active macromolecular free radicals were generated on polypropylene (PP) fibers surfaces by argon (Ar) plasma irradiation, then, PP surface modified fibers (PP-g-St fibers) were prepared by in-situ grafting reaction of styrene monomers (St). Effects of reaction parameters on grafting percentage were studied and adsorption capacities of PP-g-St fibers for benzene, toluene and xylene (BTX) were evaluated. Afterwards, regeneration adsorption efficiencies after maximum adsorption were explored. The results indicated that the optimum input power, irradiation time and grafting reaction time are 90 W, 3 min and 3 h respectively and the grafting percentage of St reached 5.7 %. The adsorption capacities of PP-g-St fibers towards toluene and xylene emulsions and solutions in water increased by 336.89 % and 344.57 % respectively, compared to pristine PP fibers. In addition, regeneration adsorption efficiencies of modified fibers remained > 90 % after six cycles of regeneration-adsorption experiments, which showed excellent regeneration ability.

  18. The volumetric properties of (1,2-propanediol carbonate+benzene, or toluene, or styrene) binary mixtures at temperatures from T=293.15 K to T=353.15 K

    International Nuclear Information System (INIS)

    Wang Haijun; Wu Yonghua; Huang Jihou

    2006-01-01

    The densities and excess molar volumes V m E for binary liquid mixtures of (1,2-propanediol carbonate+benzene, or toluene, or ethylbenzene, or styrene) have been measured as a function of compositions using a vibrating-tube densimeter in the temperature range of (293.15 to 353.15) K and at atmospheric pressure. The V m E results were correlated using the fourth-order Redlich-Kister equation. It was found that the V m E in these systems studied increases with rising temperature

  19. Phase diagrams for binary liquid system tetradecane-neodymium(III) nitrate tri-n-butyl phosphate solvate and ternary liquid systems tetradecane-n-octanol (n-butanol, o-xylene, toluene)- neodymium(III) nitrate tri-n-butyl phosphate solvate at various temperatures

    International Nuclear Information System (INIS)

    Pyartman, A.K.; Kudrova, A.V.; Keskinov, V.A.

    2005-01-01

    Phase diagrams at temperatures from 298.15 to 344.85 K were studied for the binary liquid system tetradecane-neodymium(III) nitrate tri-n-butyl phosphate solvate and ternary liquid systems tetradecane-n-octanol (n-butanol, o-xylene, toluene)-neodymium(III) nitrate tri-n-butyl phosphate (TBP) solvate. The ternary phase diagrams consist of a homogeneous solution field and a liquid-liquid phase separation field: phase I is rich in tetradecane, and phase II is rich in [Nd(NO 3 ) 3 (TBP) 3 ]. The miscibility gaps in the binary system and the ternary systems narrow with an increase in temperature. The compositions at the critical solution points of the ternary system at various temperatures were determined [ru

  20. A review of environmental and occupational exposure to xylene and its health concerns.

    Science.gov (United States)

    Niaz, Kamal; Bahadar, Haji; Maqbool, Faheem; Abdollahi, Mohammad

    2015-01-01

    Xylene is a cyclic hydrocarbon, and an environmental pollutant. It is also used in dyes, paints, polishes, medical technology and different industries as a solvent. Xylene easily vaporizes and divides by sunlight into other harmless chemicals. The aim of the present review is to collect the evidence of the xylene toxicity, related to non-cancerous health hazards, as well as to provide possible effective measurement to minimize its risk ratio. For current study a bibliographic search of more than 250 peer-reviewed papers in scientific data including PubMed, and Google Scholar about xylene was done. But approximately 130 peer-reviewed papers relevant to xylene were included (Figure 1(Fig. 1)). All scientific data was reviewed with key words of "xylene toxicity", "xylene toxic health effects", "environmental volatile organic compounds", "human exposure to xylene", "xylene poisoning in laboratory workers", "effects of xylene along with other hydrocarbons", "neurotoxicity of selected hydrocarbons", and "toxic effects of particular xylene isomers in animals". According to these studies, xylene is released into the atmosphere as fugitive emissions from petrochemical industries, fire, cigarette, from different vehicles. Short term exposure to mixed xylene or their individual isomers result in irritation of the nose, eyes and throat subsequently leading toward neurological, gastrointestinal and reproductive harmful effects. In addition long term exposure to xylene may cause hazardous effects on respiratory system, central nervous system, cardiovascular system, and renal system. The health concerns of xylene are well documented in animals and human. It is important to improve health policies, launch xylene related health and toxicity awareness campaigns, to get rid of its dangerous outcomes. Chronic diseases have become a threat to human globally, with special prominence in regions, where xylene is used with other chemicals (benzene, toluene etc.) especially in petroleum and

  1. Synthesis of Poly(para-aminostyrene) from 4-Chloromethyl Styrene Homopolymer and Its Styrene Copolymer

    OpenAIRE

    B. Massoumi; M. Saraei; M. Hatamzadeh; A. A. Entezami

    2010-01-01

    4-Chloromethyl styrene homopolymer and its copolymers with styrene were prepared from their corresponding 4-chloromethyl styrene and styrene monomers at 1:0, 1:1, 1:3 and 1:5 mole ratios. These homo- and copolymerswere synthesized by radical polymerization in presence of AIBN as initiator and dry toluene as solvent. Then, chloromethyl groups were converted into azidomethyl groups on the homo- and copolymers by substitution nucleophilic reaction in the presence of sodium azide (NaN3) and dry d...

  2. Replacing xylene with n-heptane for paraffin embedding.

    Science.gov (United States)

    Stockert, J C; López-Arias, B; Del Castillo, P; Romero, A; Blázquez-Castro, A

    2012-10-01

    In standard histological technique, aromatic solvents such as xylene and toluene are used as clearing agents between ethanol dehydration and paraffin embedding. In addition, these solvents are used for de-waxing paraffin sections. Unfortunately, these solvents are harmful and therefore adequate substitutes would be useful. We suggest the use of n-heptane as a convenient substitute for xylene. Paraffin sections of rat tissues processed with n-heptane and stained with hematoxylin-eosin or Masson's trichrome showed proper embedment, well preserved morphology and excellent staining.

  3. Anticonvulsant and antipunishment effects of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.W.; Coleman, J.B.; Schuler, R.; Cox, C.

    1984-01-01

    Toluene can have striking acute behavioral effects and is subject to abuse by inhalation. To determine if its actions resemble those of drugs used in the treatment of anxiety (anxiolytics), two sets of experiments were undertaken. Inasmuch as prevention of pentylenetetrazol-induced convulsions is an identifying property of this class of agents, the authors first demonstrated that pretreatment of mice with injections of toluene delayed the onset of convulsive signs and prevented the tonic extension phase of the convulsant activity in a dose-related manner. Injections of another alkyl benzene, m-xylene, were of comparable potency to toluene. Inhalation of toluene delayed the time of death after pentylenetetrazol injection in a manner related to the duration and concentration of exposure; at lower convulsant doses, inhalation of moderate concentrations (EC/sub 58/, 1300 ppm) prevented death. Treatment with a benzodiazepine receptor antagonist (Ro 15-1788) failed to reduce the anticonvulsant activity of inhaled toluene. Anxiolytics also attenuate the reduction in response rate produced by punishment with electric shock. Toluene increased rates of responding suppressed by punishment when responding was maintained under a multiple fixed-interval fixed-interval punishment schedule of reinforcement. Distinct antipunishment effects were observed in rats after 2 hr of exposure to 1780 and 3000 ppm of toluene; the rate-increasing effects of toluene were related to concentration and to time after the termination of exposure. Thus, toluene and m-xylene resemble in several respects clinically useful drugs such as the benzodiazepines. 51 references, 3 figures, 2 tables.

  4. Isolation and characterization of a novel toluene-degrading, sulfate-reducing bacterium.

    Science.gov (United States)

    Beller, H R; Spormann, A M; Sharma, P K; Cole, J R; Reinhard, M

    1996-01-01

    A novel sulfate-reducing bacterium isolated from fuel-contaminated subsurface soil, strain PRTOL1, mineralizes toluene as the sole electron donor and carbon source under strictly anaerobic conditions. The mineralization of 80% of toluene carbon to CO2 was demonstrated in experiments with [ring-U-14C]toluene; 15% of toluene carbon was converted to biomass and nonvolatile metabolic by-products, primarily the former. The observed stoichiometric ratio of moles of sulfate consumed per mole of toluene consumed was consistent with the theoretical ratio for mineralization of toluene coupled with the reduction of sulfate to hydrogen sulfide. Strain PRTOL1 also transforms o- and p-xylene to metabolic products when grown with toluene. However, xylene transformation by PRTOL1 is slow relative to toluene degradation and cannot be sustained over time. Stable isotope-labeled substrates were used in conjunction with gas chromatography-mass spectrometry to investigate the by-products of toluene and xylene metabolism. The predominant by-products from toluene, o-xylene, and p-xylene were benzylsuccinic acid, (2-methylbenzyl)succinic acid, and 4-methylbenzoic acid (or p-toluic acid), respectively. Metabolic by-products accounted for nearly all of the o-xylene consumed. Enzyme assays indicated that acetyl coenzyme A oxidation proceeded via the carbon monoxide dehydrogenase pathway. Compared with the only other reported toluene-degrading, sulfate-reducing bacterium, strain PRTOL1 is distinct in that it has a novel 16S rRNA gene sequence and was derived from a freshwater rather than marine environment. PMID:8919780

  5. Alteraciones hematológicas en trabajadores expuestos ocupacionalmente a mezcla de benceno- tolueno-xileno (BTX en una fábrica de pinturas Blood disorders among workers exposed to a mixture of benzene-toluene-xylene (BTX in a paint factory

    Directory of Open Access Journals (Sweden)

    Luis Haro-García

    2012-06-01

    Full Text Available Objetivos. Evaluar las tres series celulares sanguíneas e identificar la presencia de hipocromía, macrocitosis, leucopenia, linfocitopenia y trombocitopenia en un grupo de trabajadores expuestos a la mezcla de benceno-tolueno-xileno (BTX. Materiales y métodos. Estudio transversal donde se incluyó a 97 trabajadores de una empresa de pinturas de México a los que se les realizó una biometría hemática convencional y les fue estimada la exposición a través de la dosis diaria potencial acumulada para vapores de BTX. Resultados. Del total de trabajadores, 19,6%, mostró macrocitosis, 18,6%, linfocitopenia, 10,3% hipocromía, 7,2% trombocitopenia y 5,2% leucopenia. La asociación cruda de macrocitosis con exposición a dosis alta de mezcla de BTX fue la única significativa (OR:3,6; IC95%: 1,08 - 13,9; p=0,02 y en la que se estructuró un modelo de regresión logística (OR:6,7; IC95%: 1,33 - 13,55; p:0,02 ajustada por edad, consumo de alcohol y tabaquismo. Conclusiones. Todos los componentes citohemáticos analizados mostraron cambios leves; que podrían estar asociados con la exposición a la mezcla de BTX. De ellos, la macrocitosis podría constituirse en una manifestación precoz que merece ser vigilada.Objectives. Evaluate the three blood cell series and identify the presence of hypochromia, macrocytosis, leucopenia, lymphopenia, and thrombocytopenia in a group of workers exposed to the mixture of benzene-toluene-xylene (BTX. Materials and methods. A cross-sectional study which included 97 workers from a paint factory in Mexico. The participants underwent conventional blood count and tests for potential cumulative daily dose of BTX fumes, to estimate exposure. Results. From the total of workers, 19.6% showed macrocytosis, 18.6%, lymphopenia, hypochromia 10.3%, 7.2% and 5.2% thrombocytopenia leukopenia. The crude association of macrocytosis with exposure to high doses of BTX mixture was the only with statistical significance (OR: 3.6, 95

  6. A new condensed toluene mechanism for Carbon Bond: CB05-TU

    Science.gov (United States)

    Whitten, Gary Z.; Heo, Gookyoung; Kimura, Yosuke; McDonald-Buller, Elena; Allen, David T.; Carter, William P. L.; Yarwood, Greg

    2010-12-01

    Toluene is ubiquitous in urban atmospheres and is a precursor to tropospheric ozone and aerosol (smog). An important characteristic of toluene chemistry is the tendency of some degradation products (e.g., cresols and methyl-catechols) to form organic nitro and nitrate compounds that sequester NOx (NO and NO 2) from active participation in smog formation. Explaining the NOx sinks in toluene degradation has made mechanism development more difficult for toluene than for many other organic compounds. Another challenge for toluene is explaining sources of radicals early in the degradation process. This paper describes the development of a new condensed toluene mechanism consisting of 26 reactions, and evaluates the performance of CB05 with this new toluene scheme (Toluene Update, TU) against 38 chamber experiments at 7 different environmental chambers, and provides recommendations for future developments. CB05 with the current toluene mechanism (CB05-Base) under-predicted the maximum O 3 and O 3 production rate for many of these toluene-NOx chamber experiments, especially under low-NOx conditions ([NOx] t=0 toluene mechanism (CB05-TU) includes changes to the yields and reactions of cresols and ring-opening products, and showed better performance than CB05-Base in predicting the maximum O 3, O 3 formation rate, NOx removal rate and cresol concentration. Additional environmental chamber simulations with xylene-NOx experiments showed that the TU mechanism updates tended to improve mechanism performance for xylene.

  7. Solvent influence during radiation induced grafting of styrene in PVDF

    International Nuclear Information System (INIS)

    Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.

    2013-01-01

    Radiation-induced grafting was studied to produce styrene grafted poly(vinylidene fluoride) (PVDF) membranes. PVDF films with 0.125 mm thickness were irradiated at doses between 5 and 20 kGy in the presence of styrene/N,N-dimethylformamide (DMF), styrene/acetone or styrene/toluene solutions (1:1, v/v) at dose rate of 5 kGy h -1 by simultaneous method, using gamma rays from a Co-60, under nitrogen atmosphere and at room temperature. The films were characterized before and after modification by grafting yield (GY %), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM and EDS), differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). GY results shows that grafting increases with dose and toluene hinders the grafting, leading to a small GY comparing to DMF and acetone. It was possible to confirm the grafting of styrene by FT-IR due to the new characteristics peaks and by the TG and DSC due to changes in thermal behavior of the grafted material. SEM and EDS show surface and cross-section distribution of the grafting, which takes place on the surface and heterogeneously with toluene as solvent and homogeneously and penetrating into the inner layers of the matrix using DMF and acetone as solvent. (author)

  8. Synthesis of Poly(para-aminostyrene from 4-Chloromethyl Styrene Homopolymer and Its Styrene Copolymer

    Directory of Open Access Journals (Sweden)

    B. Massoumi

    2010-12-01

    Full Text Available 4-Chloromethyl styrene homopolymer and its copolymers with styrene were prepared from their corresponding 4-chloromethyl styrene and styrene monomers at 1:0, 1:1, 1:3 and 1:5 mole ratios. These homo- and copolymerswere synthesized by radical polymerization in presence of AIBN as initiator and dry toluene as solvent. Then, chloromethyl groups were converted into azidomethyl groups on the homo- and copolymers by substitution nucleophilic reaction in the presence of sodium azide (NaN3 and dry dimethylformamide (DMF as solvent.Finally, poly(para-amino styrene homopolymers with different mole ratios of amino group on the polymer chain were prepared by reaction of Schmidt rearrangement in the presence of 3-fluoromethane sulfonic acid from the homopolymer and its corresponding styrene copolymers having all azido methyl groups. Structures of the obtained homopolymers and copolymers were characterized by FTIR,  1H NMR, and 13CNMR spectroscopy. Solubility of the homopolymer and copolymer products wastested in some organic solvents.

  9. Radiolysis of Aqueous Toluene Solutions

    International Nuclear Information System (INIS)

    Christensen, H.C.; Gustafson, R.

    1971-04-01

    Aqueous toluene solutions have been irradiated with Co γ-rays. In unbuffered solutions the various cresol isomers are formed in a total yield of 0.45, 0.87 and 0.94 molecules/100 eV absorbed energy in argon-, N 2 O- and air - saturated solutions, respectively. The yields are reduced in acid (pH 3) solutions (G 0.14, 0.14 and 0.52, respectively) but the reduction is compensated by the formation of 1,2-di-phenylethane in yields of 0.49 and 1.60 in argon- and N 2 O-saturated solutions, respectively. Benzyl radicals are formed through an acid catalysed water elimination reaction from the initially formed hydroxymethylcyclohexadienyl radical. Phenyltolylmethanes, dimethylbiphenyls and partly reduced dimers are also formed during the radiolysis. Hydrogen is formed in the same yield as the molecular yield, g(H 2 ). Xylene isomers and benzene are formed in trace quantities. The most remarkable effects of the addition of Fe(III) ions to deaerated acid toluene solutions are the formation of benzyl alcohol and benzaldehyde and an increase in the yield of 1,2-diphenylethane

  10. Health Hazards of Xylene: A Literature Review

    OpenAIRE

    T. Rajan, Sharada; Malathi, N.

    2014-01-01

    Xylene, an aromatic hydrocarbon is widely used in industry and medical laboratory as a solvent. It is a flammable liquid that requires utmost care during its usage. On exposure the vapours are rapidly absorbed through the lungs and the slowly through the skin. Prolonged exposure to xylene leads to significant amount of solvent accumulation in the adipose and muscle tissue. This article reviews the various acute and chronic health effects of xylene through various routes of exposure.

  11. o -xylene or p -xylene + (acetic acid or tetrahydro-furan)

    African Journals Online (AJOL)

    The isothermal coefficients of pressure excess molar enthalpy for binary mixtures {o-xylene or p-xylene + acetic acid} at temperatures 313.15-473.15 K and pressure 0.2-2 MPa are negative and for binary mixtures {o-xylene or p-xylene + tetrahydrofuran (THF)} at temperatures 278. 15 K to 318.15 K and pressure 81.5 kPa ...

  12. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase.

    Science.gov (United States)

    Carlin, D A; Bertolani, S J; Siegel, J B

    2015-02-11

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  13. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, DA; Bertolani, SJ; Siegel, JB

    2015-01-01

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  14. A Study of Styrene-Butadiene Rubber Blends as Improved Flame Agents

    Science.gov (United States)

    1976-06-01

    from the following Fishera ACS grade chemicals: n-pentane, 4n percent; hexanes 20 percent; isooctane , 5 percent; toluene, 10 percent; xylene, 20 percent...Butadiene Rubber (SBR) Formulation a Use of these commercial products in carrying out the experiments required by rhis study does not constitute or imply

  15. Blends of Styrene-Butadiene-Styrene Triblock Copolymer with Random Styrene-Maleic Anhydride Copolymers

    NARCIS (Netherlands)

    Piccini, Maria Teresa; Ruggeri, Giacomo; Passaglia, Elisa; Picchioni, Francesco; Aglietto, Mauro

    2002-01-01

    Blends of styrene-butadiene-styrene triblock copolymer (SBS) with random styrene-maleic anhydride copolymers (PS-co-MA), having different MA content, were prepared in a Brabender Plastigraph mixer. The presence of polystyrene (PS) blocks in the SBS copolymer and the high styrene content (93 and 86

  16. pKJ1, a naturally occurring conjugative plasmid coding for toluene degradation and resistance to streptomycin and sulfonamides

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K.; Nishi, T.

    1980-08-01

    Pseudomonas sp. TA8 isolated by m-toluate enrichment from an aqueous sample metabolized toluene and m- and p-xylenes via the meta cleavage pathway, and manifested specific resistance to streptomycin and sulfonamides. A variety of experiments revealed that the pKJ1 plasmid of about 150 megadaltons carried by TA8 specified both the toluene and xylene degradative function (the Tol function) and streptomycin/sulfonamide resistance. The deletion of a segment of pKJ1 (about 22 megadaltons) resulted in the loss of the Tol function. pKJ1 was not assigned to Pseudomonas incompatibility group P-1, P-2, P-3, or P-9.

  17. Reaction Mechanism for m- Xylene Oxidation in the Claus Process by Sulfur Dioxide

    KAUST Repository

    Sinha, Sourab

    2015-09-24

    In the Claus process, the presence of aromatic contaminants such benzene, toluene, and xylenes (BTX), in the H2S feed stream has a detrimental effect on catalytic reactors, where BTX form soot particles and clog and deactivate the catalysts. Among BTX, xylenes are proven to be most damaging contaminant for catalysts. BTX oxidation in the Claus furnace, before they enter catalyst beds, provides a solution to this problem. A reaction kinetics study on m-xylene oxidation by SO2, an oxidant present in Claus furnace, is presented. The density functional theory is used to study the formation of m-xylene radicals (3-methylbenzyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, and 3,5-dimethylphenyl) through H-abstraction and their oxidation by SO2. The mechanism begins with SO2 addition on the radicals through an O-atom rather than the S-atom with the release of 180.0-183.1 kJ/mol of reaction energies. This exothermic reaction involves energy barriers in the range 3.9-5.2 kJ/mol for several m-xylene radicals. Thereafter, O-S bond scission takes place to release SO, and the O-atom remaining on aromatics leads to CO formation. Among four m-xylene radicals, the resonantly stabilized 3-methylbenzyl exhibited the lowest SO2 addition and SO elimination rates. The reaction rate constants are provided to facilitate Claus process simulations to find conditions suitable for BTX oxidation. © 2015 American Chemical Society.

  18. Effects of Na and K ions on the crystallization of low-silica X zeolite and its catalytic performance for alkylation of toluene with methanol

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Haitao; Gao, Junhua; Wang, Gencun; Liu, Ping; Zhang, Kan, E-mail: gaojunhua@sxicc.ac.cn, E-mail: zhangkan@sxicc.ac.cn [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan (China)

    2014-01-15

    The crystallization of low-silica X zeolite (LSX) was studied in Na-K gel systems with different extents of replacement of Na by K while fixed content of other components. X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, infrared spectra, and nuclear magnetic resonance were used to characterize liquid and solid phase. In the synthesis of LSX, the molar ratio of K/(Na + K) affects the crystallization and the composition of final products. A higher mole fraction of K corresponded to a lower crystallization rate, higher concentration of Si in the liquid phase, and lower Si/Al ratio of the obtained LSX. The average size of LSX products steadily increased with the progressive replacement of Na by K in the initial gels, and crystal morphology of the LSX products gradually changed from round to octahedral. For alkylation of toluene with methanol over obtained LSX, the selectivity of ring alkylation product xylene decreased while the side chain alkylation products styrene and ethylbenzene increased with the increased x values except x = 0, which was due to its low crystallinity. (author)

  19. Using graphene/styrene-isoprene-styrene copolymer composite thin film as a flexible microstrip antenna for the detection of heptane vapors

    Science.gov (United States)

    Olejnik, Robert; Matyas, Jiri; Slobodian, Petr; Riha, Pavel

    2018-03-01

    Most portable devices, such as mobile phones or tablets, use antennas made of copper. This paper demonstrates the possible use of antenna constructed from electrically conductive polymer composite materials for use in those applications. The method of preparation and the properties of the graphene/styrene-isoprene-styrene copolymer as flexible microstrip antenna are described in this contribution. Graphene/styrene-isoprene-styrene copolymer toluene solution was prepared by means of ultrasound and the PET substrate was dip coated to reach a fine thin film. The main advantages of using PET as a substrate are low weight and flexibility. The final size of the flexible microstrip antenna was 10 × 25 mm with thickness of 0.48 mm (PET substrate 0.25 mm) with a weight of 0.110 g. The resulting antenna operates at a frequency of 1.8 GHz and gain ‑40.02 dB.

  20. Final Technical Report - Autothermal Styrene Manufacturing Process with Net Export of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Trubac, Robert , E.; Lin, Feng; Ghosh, Ruma: Greene, Marvin

    2011-11-29

    The overall objectives of the project were to: (a) develop an economically competitive processing technology for styrene monomer (SM) that would reduce process energy requirements by a minimum 25% relative to those of conventional technology while achieving a minimum 10% ROI; and (b) advance the technology towards commercial readiness. This technology is referred to as OMT (Oxymethylation of Toluene). The unique energy savings feature of the OMT technology would be replacement of the conventional benzene and ethylene feedstocks with toluene, methane in natural gas and air or oxygen, the latter of which have much lower specific energy of production values. As an oxidative technology, OMT is a net energy exporter rather than a net energy consumer like the conventional ethylbenzene/styrene (EB/SM) process. OMT plants would ultimately reduce the cost of styrene monomer which in turn will decrease the costs of polystyrene making it perhaps more cost competitive with competing polymers such as polypropylene.

  1. Grafting of styrene onto poly(vinylidene fluoride) films by gamma irradiation

    International Nuclear Information System (INIS)

    Ferreira, H.P.; Souza, C.P. de; Parra, D.F.; Lugao, A.B.

    2010-01-01

    Radiation induced grafting of styrene onto poly(vinylidene fluoride) (PVDF) was studied owing to the crescent interest in use of grafted films to produce membranes with ion exchange capability. A Cobalt-60 source was used, with doses of 5 and 10 kGy, at dose rate of 5 kGy.h -1 , at room temperature, inert atmosphere and according to the simultaneous method. Solutions of styrene/toluene (1:1, v/v) and styrene/N,N-dimethylformamide (DMF) (1:1, v/v) were used. The films were characterized by FT-IR spectroscopy (Infrared Spectroscopy), Differential Scanning Calorimetry (DSC), Thermogravimetric Measurement (TG) and the degree of grafting (DOG) were calculated gravimetrically. Results shown that in studied conditions, DMF allow greatest DOG than toluene and that increasing the irradiation dose correspond an increase in DOG. Infrared and thermal analyses confirmed the presence in the grafted polymers. (author)

  2. Olefin–Styrene Copolymers

    Directory of Open Access Journals (Sweden)

    Nunzia Galdi

    2016-11-01

    Full Text Available In this review are reported some of the most relevant achievements in the chemistry of the ethylene–styrene copolymerization and in the characterization of the copolymer materials. Focus is put on the relationship between the structure of the catalyst and that of the obtained copolymer. On the other hand, the wide variety of copolymer architecture is related to the properties of the material and to the potential utility.

  3. Impact of biocatalyst and moisture content on toluene/xylene mixture biofiltration

    Directory of Open Access Journals (Sweden)

    Eva Klapková

    2006-03-01

    Full Text Available The objective of this work was to determine the influence of microbial inoculation on degradation efficiency. Three biofilters were used for the treatment of waste gas. A mixture of compost and perlite (8:2 served as the packing material. One biofilter was inoculated with a constructed microbial population. The second remained uninoculated, having the natural population present in the compost. The third biofilter was uninoculated and the packing material was sterilized. The degradation ability of the uninoculated biofilter started to drop after 18 days, while the removal efficiency of inoculated biofilter was stable. The sterile biofilter proved to have no removal efficiency. Moisture content of the packing and ability of the packing to keep moisture was tested. The results showed a significant dependence of the degradation efficiency on the packing moisture content, with highest removal efficiency observed at 70 % moisture content.O objetivo deste trabalho foi determinar a influência da inoculação microbiana na eficiência da degradação. Três biofiltros foram utilizados no tratamento do gás residuais. Uma mistura de composto e perlite na proporção (8:2 serviu como o material de empacotamento dos biofiltros. Um biofiltro foi inoculado com uma população microbial selecionada. O segundo permaneceu inoculado com a população microbiana natural presente no composto. O terceiro biofiltro foi inoculado com microrganismos selecionados com o material de empacotam previamente esterilizado. A capacidade de degradação do biofiltro não inoculado começou a se reduzir após 18 dias, enquanto que a eficiência da remoção do biofiltro se manteve estável. O biofiltro estéril não apresentou nenhuma eficiência na remoção dos compostos tóxicos. O grau de umidade do material e a característica do empacotamento foi avaliado. Os resultados mostraram uma dependência significativa da eficiência de degradação com o teor de umidade do material de empacotamento , a maior elevada remoção foi observada com 70 % de índice de umidade.

  4. Shear Viscosity of Benzene, Toluene, and p-Xylene by Non-equilibrium Molecular Dynamics Simulations

    International Nuclear Information System (INIS)

    Lee, Song Hi

    2004-01-01

    Green and Kubo showed that the phenomenological coefficients describing many transport processes and time dependent phenomena in general could be written as integrals over a certain type of function called a time correlation function. The Green-Kubo formulas are the formal expressions for hydrodynamic field variables and some of the thermodynamic properties in terms of the microscopic variables of an N-particle system. The identification of microscopic expressions for macroscopic variables is made by a process of comparison of the conservation equations of hydrodynamics with the microscopic equations of change for conserved densities. The importance of these formulas is three-fold: they provide an obvious method for calculating transport coefficients using computer simulation, a convenient starting point for constructing analytic theories for non-equilibrium processes, and an essential information for designing non-equilibrium molecular dynamics (NEMD) algorithm.

  5. Rapid microbial mineralization of toluene and 1,3-dimethylbenzene in the absence of molecular oxygen

    International Nuclear Information System (INIS)

    Zeyer, J.; Kuhn, E.P.; Schwarzenbach, R.P.

    1986-01-01

    Up to 0.4 mM 1,3-dimethylbenzene (m-xylene) was rapidly mineralized in a laboratory aquifer column operated in the absence of molecular oxygen with nitrate as an electron acceptor. Under continuous flow conditions, the degradation rate constant (pseudo-first order) was >0.45 h -1 . Based on a carbon mass balance with [ring- 14 C]m-xylene and a calculation of the electron balance, m-xylene was shown to be quantitatively (80%) oxidized to CO 2 with a concomitant reduction of nitrate. The mineralization of m-xylene in the column also took place after reducing the redox potential, E', of the inflowing medium with sulfide to <-0.11 V. Microorganisms adapted to growth on m-xylene were also able to degrade toluene under denitrifying conditions. These results suggest that aromatic hydrocarbons present in anoxic environments such as lake sediments, sludge digestors, and ground water infiltration zones from landfills and polluted rivers are not necessarily persistent but may be mineralized in the absence of molecular oxygen

  6. Toluene destruction in the Claus process by sulfur dioxide: A reaction kinetics study

    KAUST Repository

    Sinha, Sourab

    2014-10-22

    The presence of aromatics such as benzene, toluene, and xylene (BTX) as contaminants in the H2S gas stream entering Claus sulfur recovery units has a detrimental effect on catalytic reactors, where BTX forms soot particles and clogs and deactivates the catalysts. BTX oxidation, before they enter catalyst beds, can solve this problem. A theoretical investigation is presented on toluene oxidation by SO2. Density functional theory is used to study toluene radical (benzyl, o-methylphenyl, m-methylphenyl, and p-methylphenyl)-SO2 interactions. The mechanism begins with SO2 addition on the radical through one of the O atoms rather than the S atom. This exothermic reaction involves energy barriers of 4.8-6.1 kJ/mol for different toluene radicals. Thereafter, O-S bond scission takes place to release SO. The reaction rate constants are evaluated to facilitate process simulations. Among four toluene radicals, the resonantly stabilized benzyl radical exhibited lowest SO2 addition rate. A remarkable similarity between toluene oxidation by O2 and by SO2 is observed.

  7. "Occupational Exposure To Xylene In Workers, Employing At Pathology Wards Of Hospitals Belonging To The Qazvin University Of Medical Sciences "

    Directory of Open Access Journals (Sweden)

    Shah Taheri SJ

    2005-05-01

    Full Text Available Background: Nowadays, aromatic hydrocarbons such as benzene, toluene, and xylene are extensively used in the different environments and industries, causing adverse effects on individuals who are being exposed occupationally and environmentally to these hazardous compounds. In this study, occupational exposure to xylene in workers, employing at pathology wards of hospitals belonging to the Qazvin University of Medical Sciences have been investigated. Materials and Methods: Methyl Hiporic Acid (MHA as a main metabolite of xylene in urine was used to evaluate the workers exposure to this chemical. The urine samples were taken from all 30 workers from 4 hospitals, i.e. Kosar, Shahid Rajaei, Booali and Qods. Through this study, 30 administrative employees were also selected as control group. The direct DBA colorimetric method was used to measure MHA in the workers urine. Results: The results obtained from this study showed that, there were significant differences between MHA and working days, type of jobs, and length of exposure time. This study also showed that, there were no significant differences between urinary MHA concentration and sex, age, and smoking habit. Conclusion: Through this study, it was also clearly obtained that, xylene exposure can not affect on the total and direct serum bilirobin in the workers blood. Finally, it is worth mentioning that, although this study showed no acute exposure to xylene in hospitals pathology wards, the effect of chronic exposure to such compound cannot be ignored, therefore protecting workers against like these organic solvents are strongly recommended as their TLVs are considerably being reduced during these years

  8. Volatilisation of o-Xylene from Sandy Soil

    DEFF Research Database (Denmark)

    Lindhardt, Bo; Christensen, Thomas Højlund; Brun, Adam

    1994-01-01

    The diffusive release of o-xylene from two soils with different contents of organic carbon (1.1 % and 0.11 % TOC) and with two different water contents (app. 5 % w/w and 15 % w/w was studied in the laboratory. The soils were spiked with o-xylene in the laboratory. The fluxes were measured over...

  9. Novel Non-Toxic Xylene Substitute (SBO) for Histology | Kunhua ...

    African Journals Online (AJOL)

    SBO had a high boiling point (188°C) and flash point (144°C) coupled with a scentless and decreased volatility. To compare the effectiveness of SBO and xylene in histology, a wide range of tissue samples from rats and human beings were processed in parallel in SBO and xylene, subjected to various staining procedures.

  10. Toluene monooxygenase from the fungus Cladosporium sphaerospermum

    NARCIS (Netherlands)

    Luykx, D.M.A.M.; Prenafeta-Boldu, F.X.; Bont, de J.A.M.

    2003-01-01

    Assimilation of toluene by Cladosporium sphaerospermum is initially catalyzed by toluene monooxygenase (TOMO). TOMO activity was induced by adding toluene to a glucose-pregrown culture of C. sphaerospermum. The corresponding microsomal enzyme needed NADPH and O2 to oxidize toluene and glycerol,

  11. Review: Microbial degradation of toluene | Gopinath | African ...

    African Journals Online (AJOL)

    In spite of positive potential application, toluene results in many mishaps especially health hazards; hence amputation of toluene is crucial for human welfare as well as environmental issues. This review deals with destruction of toluene using microbial degradation. The overall aerobic biodegradation of toluene into carbon ...

  12. Solvent and irradiation doses effects on the ion exchange capacity of sulfonated styrene grafted PVDF

    International Nuclear Information System (INIS)

    Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.

    2011-01-01

    Polymers exhibiting ion exchange capacity are studied for many years due to their application in several fields, such as membranes for proton exchange fuel cells, filtration membranes, heavy ions recovery and artificial muscles and sensors. Radiation induced grafting followed by sulfonation is a well-known way to obtain ion exchange polymers. Fluorinated polymers are frequently used as polymeric matrix for grafting due to their excellent physicochemical properties. Radiation induced grafting of styrene into poly (vinylidene fluoride) (PVDF) by simultaneous method in 1:1 styrene/toluene or styrene/N,N-dimethylformamide solutions was studied. Irradiations were performed under nitrogen atmosphere, room temperature and at doses of 5, 10 and 20 kGy with dose rate of 5 kGy.h -1 from a 60 Co gamma source. After washing, grafted materials were sulfonated in 10% chlorosulfonic acid/1,2-dichloroethane solutions for 4 h at room temperature. Characterization shows that increasing irradiation dose corresponds to increases in the grafting yield (GY %) gravimetrically calculated and these different solvents shows different grafting behaviors. Toluene allows no more than 3 % of grafting while DMF allows up to 55 % of grafting in the same condition. Grafting in toluene solution occurs on the surface and in DMF solution it occurs in the bulk, as confirmed by SEM. Both irradiation doses and solvent used have direct effects in the ion exchange capacities (calculated after titrations). FT-IR spectra exhibit new peaks after grafting and after sulfonation, attributed to grafted monomer and sulfonic groups attached to the styrene. DSC shows differences in thermal behavior of the polymer before and after each step. (author)

  13. Solvent and irradiation doses effects on the ion exchange capacity of sulfonated styrene grafted PVDF

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Polymers exhibiting ion exchange capacity are studied for many years due to their application in several fields, such as membranes for proton exchange fuel cells, filtration membranes, heavy ions recovery and artificial muscles and sensors. Radiation induced grafting followed by sulfonation is a well-known way to obtain ion exchange polymers. Fluorinated polymers are frequently used as polymeric matrix for grafting due to their excellent physicochemical properties. Radiation induced grafting of styrene into poly (vinylidene fluoride) (PVDF) by simultaneous method in 1:1 styrene/toluene or styrene/N,N-dimethylformamide solutions was studied. Irradiations were performed under nitrogen atmosphere, room temperature and at doses of 5, 10 and 20 kGy with dose rate of 5 kGy.h{sup -1} from a {sup 60}Co gamma source. After washing, grafted materials were sulfonated in 10% chlorosulfonic acid/1,2-dichloroethane solutions for 4 h at room temperature. Characterization shows that increasing irradiation dose corresponds to increases in the grafting yield (GY %) gravimetrically calculated and these different solvents shows different grafting behaviors. Toluene allows no more than 3 % of grafting while DMF allows up to 55 % of grafting in the same condition. Grafting in toluene solution occurs on the surface and in DMF solution it occurs in the bulk, as confirmed by SEM. Both irradiation doses and solvent used have direct effects in the ion exchange capacities (calculated after titrations). FT-IR spectra exhibit new peaks after grafting and after sulfonation, attributed to grafted monomer and sulfonic groups attached to the styrene. DSC shows differences in thermal behavior of the polymer before and after each step. (author)

  14. Radiation effects on styrene-butadiene-styrene copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yan; Zhao Sufang; Li Yintao [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Xie Leidong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)], E-mail: xieleidong@sinap.ac.cn; Sheng Kanglong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2008-08-15

    Styrene-butadiene-styrene copolymer (SBS) of different configuration and block ratio were irradiated by {sup 60}Co {gamma}-rays at 20 deg. C and 120 deg. C. The gel fraction and thermal properties before and after irradiation were discussed. The gel fraction increased with both absorbed doses and temperature. This means higher crosslinking efficiency was obtained at higher temperature. The radiation chemical yields were calculated according to the Charlesby-Pinner equation. The DSC analysis indicated that the crosslinking had taken place in the polybutadiene (PB) block while the chain scission of polystyrene (PS) block was dominant when irradiated at elevated temperature.

  15. Grafting of styrene onto poly(vinylidene fluoride) films by gamma irradiation; Enxertia de estireno em filmes de poli(fluoreto de vinilideno) induzida por irradiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, H.P.; Souza, C.P. de; Parra, D.F.; Lugao, A.B., E-mail: hp.ferreira@yahoo.com.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2010-07-01

    Radiation induced grafting of styrene onto poly(vinylidene fluoride) (PVDF) was studied owing to the crescent interest in use of grafted films to produce membranes with ion exchange capability. A Cobalt-60 source was used, with doses of 5 and 10 kGy, at dose rate of 5 kGy.h{sup -1}, at room temperature, inert atmosphere and according to the simultaneous method. Solutions of styrene/toluene (1:1, v/v) and styrene/N,N-dimethylformamide (DMF) (1:1, v/v) were used. The films were characterized by FT-IR spectroscopy (Infrared Spectroscopy), Differential Scanning Calorimetry (DSC), Thermogravimetric Measurement (TG) and the degree of grafting (DOG) were calculated gravimetrically. Results shown that in studied conditions, DMF allow greatest DOG than toluene and that increasing the irradiation dose correspond an increase in DOG. Infrared and thermal analyses confirmed the presence in the grafted polymers. (author)

  16. Heterogeneous catalytic oxidative dehydrogenation of ethylbenzene to styrene with carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Badstube, T.; Papp, H. [Leipzig Univ. (Germany). Inst. fuer Technische Chemie; Kustrowski, P.; Dziembaj, R. [Jagiellonian Univ., Crakow (Poland). Faculty of Chemistry

    1998-12-31

    Alkaline promoted active carbon supported iron catalysts are very active in the oxidative dehydrogenation of ethylbenzene to styrene in the presence of carbon dioxide. The best results were obtained at 550 C for a Li-promoted catalyst with a conversion of ethylbenzene of 75% and a selectivity towards styrene of nearly 95%. These results are better than those obtained with industrial catalysts which perform the dehydrogenation process with an excess of water. The main product of the dehydrogenation reaction with CO{sub 2} was styrene, but the following by-products were detected - benzene and toluene. The selectivity towards toluene was always higher than towards benzene. We observed also the formation of carbon monoxide and water, which were produced with a constant molar ratio of about 0.8. The weight of the catalysts increased up to 20% during the reaction due to deposition of carbon. Using a too large excess of CO{sub 2} (CO{sub 2}/EB>10) was harmful for the styrene yield. The most favorable molar ratio of CO{sub 2} to EB was 10:1. No correlation between the molar ratios of reactants and the amount of deposited coke on the surface of catalysts was observed. The highest catalytic activity showed iron loaded D-90 catalysts which were promoted with alkali metals in a molar ratio of 1:10. Iron, nickel and cobalt loaded carbonized PPAN, PC, inorganic supports like Al{sub 2}O{sub 3}, SiO{sub 2}/ZrO{sub 2} or TiO{sub 2} respectively and commercial iron catalysts applied for styrene production did not show comparable catalytic activity in similar conditions. (orig.)

  17. Blending of styrene-block-butadiene-block-styrene copolymer with sulfonated vinyl aromatic polymers

    OpenAIRE

    Ruggeri, Giacomo; Passaglia, Elisa; Giorgi, Ivan; Picchioni, Francesco; Aglietto, Mauro

    2001-01-01

    Different polymers containing sulfonic groups attached to the phenyl rings were prepared by sulfonation of polystyrene (PS) and styrene-block-(ethylene-co-1-butene)-block-styrene (SEBS). The sulfonation degree (SD) was varied between 1 and 20 mol% of the styrene units. Polyphase materials containing sulfonated units were prepared by blending styrene-block-butadiene-block-styrene (SBS), with both sulfonated PS and sulfonated SEBS in a Brabender mixer. Such a procedure was performed as an alter...

  18. Performance of rare earth modified faujasites in the process of toluene disproportionation

    International Nuclear Information System (INIS)

    Azzouz, A.; Fourar, M.; Berrak, A.

    1984-06-01

    The purpose of the present paper is the study of the performances of some catalysts based on y-type faujasite exchanged with La (3+) and Ce (3+) cations in the process of toluene disproportionation to benzene and xylenes. In the first stage the crystallographic study by the X-rays diffraction method shows that the cation exchange causes 311 plane displacements in the zeolite structure, accompanied by a decrease of diffraction limit intensity. Further the faujasite pretreatment with NH4 (4+) ions plays some role in the protection of the crystallinity. Moreover the cation exchange seems to take an optimum value around 73% for which the toluene conversion is maximum. This phenomenon is probably due to a decrease of the internal free volume for a pronounced cation exchange. The best performances are obtained by the zeolite that has undergone a slow and programmed thermal activation after cation exchange. This is probably due to the slowness of ion rearrangement phenomena, and of the catalytic surface restructuration. In the second stage the realization of toluene disproportionation process shows that the cation exchange with such elements confers to the faujasite an appreciable catalytic activity in the temperature range of 350-500 degC. The catalysts obtained permit about 20-60% toluene conversions. The catalytic activity is slightly higher in La-modified samples, whereas those containing Ce (3+) present relatively a better selectivity to the main process. Nevertheless, both types of catalysts show approximately a similar behaviour, favourizing the p-xylene formation. The proportion of the latter exceeds that of thermodynamic equilibrium at temperatures less than 430 degC. The temperature increase affects this selectivity. This is probably due to dehydration phenomenon which are frequent around this value

  19. DETERMINATION OF A BOUND MUSK XYLENE ...

    Science.gov (United States)

    Musk xylene (MX) is widely used as a fragrance ingredient in commercial toiletries. Identification and quantification of a bound 4-amino-MX (AMX) metabolite was carried out by gas chromatography-mass spectrometry (GC/MS), with selected ion monitoring (SIM). Detection of AMX occurred after the cysteine adducts in carp hemoglobin, derived from the nitroso metabolite, were released by alkaline hydrolysis. The released AMX metabolite was extracted into n-hexane. The extract was preconcentrated by evaporation, and analyzed by GC-SIM-MS. The concentration of AMX metabolite was found to range from 6.0 to 30.6 ng/g in the carp Hb, collected from the Las Vegas Wash and Lake Mead, Nevada areas. The presence of an AMX metabolite in the carp Hb was confirmed when similar mass spectral features and the same retention time of the AMX metabolite were obtained for both standard AMX and carp Hb extract solutions. In the non-hydrolyzed and reagent blank extracts, the AMX metabolite was not detected. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers,

  20. Transformation of Nitrate and Toluene in Groundwater by Sulfur Modified Iron(SMI-III)

    Science.gov (United States)

    Lee, W.; Park, S.; Lim, J.; Hong, U.; Kwon, S.; Kim, Y.

    2009-12-01

    In Korea, nitrate and benzene, toluene, ethylbenzene, and xylene isomers (BTEX) are frequently detected together as ground water contaminants. Therefore, a system simultaneously treating both nitrate (inorganic compound) and BTEX (organic compounds) is required to utilize groundwater as a water resource. In this study, we investigated the efficiency of Sulfur Modified Iron (SMI-III) in treating both nitrate and BTEX contaminated groundwater. Based on XRD (X-Ray Diffraction) analysis, the SMI-III is mainly composed of Fe3O4, S, and Fe. A series of column tests were conducted at three different empty bed contact times (EBCTs) for each compound. During the experiments, removal efficiency for both nitrate and toluene were linearly correlated with EBCT, suggesting that SMI-III have an ability to transform both nitrate and toluene. The concentration of SO42- and oxidation/reduction potential (ORP) were also measured. After exposed to nitrate contaminated groundwater, the composition of SMI-III was changed to Fe2O3, Fe3O4, Fe, and Fe0.95S1.05. The trends of effluent sulfate concentrations were inversely correlated with effluent nitrate concentrations, while the trends of ORP values, having the minimum values of -480 mV, were highly correlated with effluent nitrate concentrations. XRD analysis before and after exposed to nitrate contaminated groundwater, sulfate production, and nitrite detection as a reductive transformation by-product of nitrate suggest that nitrate is reductively transformed by SMI-III. Interestingly, in the toluene experiments, the trends of ORP values were inversely correlated with effluent toluene concentrations, suggesting that probably degrade through oxidation reaction. Consequently, nitrate and toluene probably degrade through reduction and oxidation reaction, respectively and SMI-III could serve as both electron donor and acceptor.

  1. Xylenes transformation over zeolites ZSM-5 ruled by acidic properties

    Science.gov (United States)

    Gołąbek, Kinga; Tarach, Karolina A.; Góra-Marek, Kinga

    2018-03-01

    The studies presented in this work offer an insight into xylene isomerization process, followed by 2D COS analysis, in the terms of different acidity of microporous zeolites ZSM-5. The isomerisation reaction proceeded effectively over zeolites ZSM-5 of Si/Al equal of 12 and 32. Among them, the Al-poorer zeolite (Si/Al = 32) was found to offer the highest conversion and selectivity to p-xylene with the lowest number of disproportionation products, both in ortho- and meta-xylene transformation. Further reduction of Brønsted acidity facilitated the disproportionation path (zeolites of Si/Al = 48 and 750). The formation of intermediate species induced by the diffusion constraints for m-xylene in 10-ring channels was rationalized in the terms of the methylbenzenium ions formation inside the rigid micropore environment. Finally, both microporous character of zeolite and the optimised acidity were found to be crucial for high selectivity to the most desired product i.e. p-xylene. The analysis of asynchronous maps allowed for concluding on the order of the appearance of the respective products on the zeolite surface.

  2. Toluene stability Space Station Rankine power system

    Science.gov (United States)

    Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

    1987-01-01

    A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

  3. Toxicity of the styrene metabolite, phenylglyoxylic acid, in rats after three months' oral dosing

    DEFF Research Database (Denmark)

    Ladefoged, Ole; Lam, Henrik Rye; Ostergaard, G.

    1998-01-01

    a functional observational battery or radial arm maze. An increased relative kidney weight was seen in the highest dose-group (Controls: 0.504 +/- 0.031 g/100 g b. wt.; 5000 mg PGA/I: 0.579 +/- 0.033 g/100 g b.wt.; porgan weights were affected. Histopathology revealed no change in kidney....... Alternatively, the ototoxicity of styrene, like toluene, may be caused the parent compound itself and not by a metabolite like PGA. (C) 1998 Inter Press, inc....

  4. Blending of styrene-block-butadiene-block-styrene copolymer with sulfonated vinyl aromatic polymers

    NARCIS (Netherlands)

    Ruggeri, Giacomo; Passaglia, Elisa; Giorgi, Ivan; Picchioni, Francesco; Aglietto, Mauro

    2001-01-01

    Different polymers containing sulfonic groups attached to the phenyl rings were prepared by sulfonation of polystyrene (PS) and styrene-block-(ethylene-co-1-butene)-block-styrene (SEBS). The sulfonation degree (SD) was varied between 1 and 20 mol% of the styrene units. Polyphase materials containing

  5. Acute neurobehavioural effects of toluene.

    OpenAIRE

    Echeverria, D; Fine, L; Langolf, G; Schork, A; Sampaio, C

    1989-01-01

    An acute inhalation chamber study of 42 college students was performed to investigate the relation between exposure to 0, 75, and 150 ppm of toluene and changes in central nervous system function and symptoms. Paid subjects were exposed for seven hours over three days. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory); perception (pattern recognition); psychomotor skill (simple reaction time, continuous performance, digit symbol, hand-eye coordination, finger...

  6. Acute neurobehavioural effects of toluene.

    Science.gov (United States)

    Echeverria, D; Fine, L; Langolf, G; Schork, A; Sampaio, C

    1989-07-01

    An acute inhalation chamber study of 42 college students was performed to investigate the relation between exposure to 0, 75, and 150 ppm of toluene and changes in central nervous system function and symptoms. Paid subjects were exposed for seven hours over three days. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory); perception (pattern recognition); psychomotor skill (simple reaction time, continuous performance, digit symbol, hand-eye coordination, finger tapping, and critical tracking); manual dexterity (one hole); mood (profile of mood scales (POMS]; fatigue (fatigue checklist); and verbal ability were evaluated at 0800, 1200, and 1600 hours. Voluntary symptoms and observations of sleep were collected daily. An analysis of variance and test for trend was performed on the difference and score for each concentration reflecting an eight hour workday where each subject was their own control. A 3 x 3 Latin square study design evaluated toluene effects simultaneously, controlling for learning across the three days and the solvent order. Intersubject variation in solvent uptake was monitored in breath and urine. A 5-10% decrement in performance was considered significant if it was consistent with a linear trend at p less than 0.05. Adverse performance at 150 ppm toluene was found at 6.0% for digit span, 12.1% for pattern recognition (latency), 5.0% for pattern memory (number correct), 6.5% for one hole, and 3.0% for critical tracking. The number of headaches and eye irritation also increased in a dose response manner. The greatest effect was found for an increasing number of observations of sleep. Overall, no clear pattern of neurobehavioural effects was found consistent with the type 1 central nervous system as classified by the World Health Organisation. Subtle acute effects, however, were found just below and above the ACGIH TLV of 100 ppm toluene, supporting the position that the guideline be lowered since the biological

  7. Vibrational, conformational and electronic structure investigations of α,α'-dibromo-o-xylene, α,α'-dibromo-m-xylene and α,α'-dibromo-p-xylene

    Science.gov (United States)

    Arjunan, V.; Saravanan, I.; Mythili, C. V.; Balakrishnan, K.; Mohan, S.

    2012-06-01

    The Fourier transform infrared (FTIR) and FT-Raman spectra of α,α'-dibromo-o-xylene (DBOX), α,α'-dibromo-m-xylene (DBMX) and α,α'-dibromo-p-xylene (DBPX) of the configuration BrCH2sbnd C6H4sbnd CH2Br have been recorded in the range 4000-400 and 4000-100 cm-1, respectively. The conformational analysis of these compounds was performed. The complete vibrational assignment and analysis of the fundamental modes of the most stable conformer of the compounds were carried out using the experimental FTIR and FT-Raman data, and quantum mechanical studies. The observed vibrational frequencies were compared with the wavenumbers derived theoretically for the optimized geometry of the compounds from the DFT-B3LYP gradient calculations employing the standard 6-31G**, high level 6-311++G** and cc-pVTZ basis sets. The structural parameters and vibrational wavenumbers obtained from the DFT method are in good agreement with the experimental data. The potential energy distributions of the fundamental modes were also calculated with DFT force fields utilizing Wilson's FG matrix method. The effect of sbnd CH2Br group on the skeletal vibrations has been discussed.

  8. Photoinitiator grafted styrene-butadiene-styrene triblock copolymer

    International Nuclear Information System (INIS)

    Wu Guoliang; Zeng Songjun; Ou Encai; Yu Puren; Lu Yanbing; Xu Weijian

    2010-01-01

    Grafting of photoinitiator-4-maleimidobenzophenone (4-MBP) onto styrene-butadiene-styrene (SBS) triblock copolymer was carried out by free radical polymerization. The grafting ratio was evaluated by varying initiator concentrations, and the structure of grafted copolymer (SBS-g-MBP) was characterized by attenuated total reflectance infrared Fourier transform spectroscopy (ATR-FTIR), proton nuclear magnetic resonance ( 1 H NMR) and X-ray photoelectron spectroscopy (XPS). The results confirmed that 4-MBP was successfully grafted onto the SBS backbone. Thermal gravimetric analyzer (TGA), dynamic mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to study the thermal properties and morphology of the SBS-g-MBP. From the data of TGA, the SBS-g-MBP had better thermal stability compared with that of SBS. DMTA testing indicated that the glass transition temperature (T g ) of SBS-g-MBP was higher than that of SBS. With the aid of SEM and AFM, the structure of micro-phase separation can be observed obviously. What is more, the aggregates become smaller compared with those of pure SBS. The experiment of UV-crosslinked SBS-g-MBP revealed that the gel fraction could be facilely controlled by adjusting grafting ratio and exposure time. The results suggested that this novel grafted copolymer could be attractive for its application in biomedical materials such as medical pressure-sensitive adhesive.

  9. Helbredsrisici ved eksponering for styren i glasfiberplastindustrien

    DEFF Research Database (Denmark)

    Kolstad, Henrik Albert; Ebbehøj, Nielse; Bonde, Jens Peter

    2012-01-01

    or relevant exposure levels. We recommend reconsideration of the current Danish threshold limit value of 25 ppm, biological monitoring of styrene exposed workers, and epidemiological analyses of styrene exposure levels and long-term health effects among employees of the Danish reinforced plastics industry....

  10. Stereochemical metabolism of styrene in volunteers

    NARCIS (Netherlands)

    Wenker, M. A.; Kezić, S.; Monster, A. C.; de Wolff, F. A.

    2001-01-01

    To study the stereochemistry of styrene metabolism in volunteers, and its interindividual variability. Twenty healthy male volunteers (aged 18-37 years) were exposed to 360 mg/m3 styrene for 1 h while they performed 50 W physical exercise. Venous blood was drawn during and for up to 2 h after

  11. Kinetic Aspects of the Direct Electrochemical Oxidation of p -Xylene ...

    African Journals Online (AJOL)

    ... the fraction of A remaining at a particular time. It is shown that the calculated curves agree well with those based on the observed values, indicating that the proposed kinetic model is acceptable. Key words: p-xylene. Electrochemical oxidation, Parallel second order consecutive kinetics. South African Journal of Chemistry ...

  12. A Green Alternative to Aluminum Chloride Alkylation of Xylene

    Science.gov (United States)

    Sereda, Grigoriy A.; Rajpara, Vikul B.

    2007-01-01

    An acutely less toxic 2-bromobutane is used to develop a simple graphite-promoted procedure of alkylation of p-xylene. It is further demonstrated that aluminum chloride is not required, the need for aqueous workup is eliminated, waste solutions are not produced and the multiple use of the catalyst is allowed.

  13. Toluene combustion: reaction paths, thermochemical properties, and kinetic analysis for the methylphenyl radical + O2 reaction.

    Science.gov (United States)

    da Silva, Gabriel; Chen, Chiung-Chu; Bozzelli, Joseph W

    2007-09-06

    Aromatic compounds such as toluene and xylene are major components of many fuels. Accurate kinetic mechanisms for the combustion of toluene are, however, incomplete, as they do not accurately model experimental results such as strain rates and ignition times and consistently underpredict conversion. Current kinetic mechanisms for toluene combustion neglect the reactions of the methylphenyl radicals, and we believe that this is responsible, in part, for the shortcomings of these models. We also demonstrate how methylphenyl radical formation is important in the combustion and pyrolysis of other alkyl-substituted aromatic compounds such as xylene and trimethylbenzene. We have studied the oxidation reactions of the methylphenyl radicals with O2 using computational ab initio and density functional theory methods. A detailed reaction submechanism is presented for the 2-methylphenyl radical + O2 system, with 16 intermediates and products. For each species, enthalpies of formation are calculated using the computational methods G3 and G3B3, with isodesmic work reactions used to minimize computational errors. Transition states are calculated at the G3B3 level, yielding high-pressure limit elementary rate constants as a function of temperature. For the barrierless methylphenyl + O2 and methylphenoxy + O association reactions, rate constants are determined from variational transition state theory. Multichannel, multifrequency quantum Rice-Ramsperger-Kassel (qRRK) theory, with master equation analysis for falloff, provides rate constants as a function of temperature and pressure from 800 to 2400 K and 1 x 10(-4) to 1 x 10(3) atm. Analysis of our results shows that the dominant pathways for reaction of the three isomeric methylphenyl radicals is formation of methyloxepinoxy radicals and subsequent ring opening to methyl-dioxo-hexadienyl radicals. The next most important reaction pathway involves formation of methylphenoxy radicals + O in a chain branching process. At lower

  14. Application of La-ZSM-5 Coated Silicon Carbide Foam Catalyst for Toluene Methylation with Methanol

    Directory of Open Access Journals (Sweden)

    Debarpita Ghosal

    2015-07-01

    Full Text Available The performance of toluene methylation reaction was studied on H-ZSM-5 catalyst modified with La, Ce and Nb at different percentage loading. It was found that 10% metal loading produced the best performance in the reaction in terms of toluene conversion. The catalyst was coated on silicon carbide foam support which showed better conversion than the pelleted catalyst. Again, among the treated and untreated H-ZSM-5, the La-ZSM-5 catalyst is chosen for the reaction for its highest selectivity towards xylene, the main product. All catalysts were characterized in terms of surface properties, SEM, XRD and NH3-TPD. Kinetic study was done on La-ZSM-5 catalyst with 10% loading. In this kineticstudy, Langmuir Hinshelwood kinetic model with surface reaction as rate controlling step was selected as the rate equation. The activation energy was found to be 47 kJ/mol. © 2015 BCREC UNDIP. All rights reserved. Received: 9th December 2014; Revised: 27th April 2015; Accepted: 29th April 2015  How to Cite: Ghosal, D., Basu, J.K., Sengupta, S. (2015. Application of La-ZSM-5 Coated Silicon Carbide Foam Catalyst for Toluene Methylation with Methanol. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 201-209. (doi:10.9767/bcrec.10.2.7872.201-209 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.7872.201-209  

  15. Health risk assessment of ambient air concentrations of benzene, toluene and xylene (BTX) in service station environments.

    Science.gov (United States)

    Edokpolo, Benjamin; Yu, Qiming Jimmy; Connell, Des

    2014-06-18

    A comprehensive evaluation of the adverse health effects of human exposures to BTX from service station emissions was carried out using BTX exposure data from the scientific literature. The data was grouped into different scenarios based on activity, location and occupation and plotted as Cumulative Probability Distributions (CPD) plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ) at 50% (CEXP50) and 95% (CEXP95) exposure levels. HQ50 and HQ95 > 1 were obtained with benzene in the scenario for service station attendants and mechanics repairing petrol dispensing pumps indicating a possible health risk. The risk was minimized for service stations using vapour recovery systems which greatly reduced the benzene exposure levels. HQ50 and HQ95 service station attendants than any other scenario.

  16. ATOM TRANSFER RADICAL POLYMERIZATION OF STYRENE IN TOLUENE-WATER MIXTURES. (R829580)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  17. Helbredsrisici ved eksponering for styren i glasfiberplastindustrien

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Ebbehøj, Nielse; Bonde, Jens Peter

    2012-01-01

    This is a summary of the health risks of occupational styrene exposure based on recent reviews. We conclude about the exposure levels that there is strong evidence that styrene causes acute irritation of eyes and respiratory tract above 25 ppm, genotoxic effects above 10 ppm, and persistent nervous...... system effects with for instance reduced psychological performance, colour discrimination and hearing level following long-term styrene exposure above 10 ppm. There is moderate evidence of a causal association with cancer, but data are not sufficient to allow us to pinpoint specific cancers at risk...

  18. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

    Hougaard, K. S.; Hansen, A. M.; Hass, Ulla

    2003-01-01

    of corticosteroids from the maternal to the foetal compartment. Pregnant rats were subjected to either 1500 ppm toluene 6 hr/day and/or a schedule of "Chronic mild stress" during the last two weeks of gestation. Exposure to toluene was associated with reduced birth weight and lower maternal weight gain, the latter...

  19. Alkylation of toluene with isopropyl alcohol over SAPO-5 catalyst

    Indian Academy of Sciences (India)

    cymene; isopropylation; toluene; SAPO-5. Abstract. Isopropylation of toluene with isopropyl alcohol was studied over the large pore silicon alumino phosphate molecular sieves (SAPO-5) with varying Si content. Toluene conversion was found ...

  20. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

    Hougaard, Karin S; Hansen, Åse Marie; Hass, Ulla

    2003-01-01

    Combined exposure to stressors and chemicals may result in synergistic effects. The effects of prenatal exposure to the organic solvent toluene resemble those observed in offspring of gestationally stressed dams, a possible common mechanism being transfer of stress-/toluene-induced increments...... of corticosteroids from the maternal to the foetal compartment. Pregnant rats were subjected to either 1500 ppm toluene 6 hr/day and/or a schedule of "Chronic mild stress" during the last two weeks of gestation. Exposure to toluene was associated with reduced birth weight and lower maternal weight gain, the latter...... being enhanced by maternal stress. A depressant effect of toluene on maternal corticosterone was observed, hence the study does not provide immediate evidence that transfer of elevated levels of corticosterone from the maternal to the foetal compartment mediates the effects of prenatal exposure...

  1. Separation and effect of residual moisture in liquid phase adsorption of xylene on y zeolites

    Directory of Open Access Journals (Sweden)

    P. Lahot

    2014-06-01

    Full Text Available The separation of p-xylene and m-xylene from C8 aromatic hydrocarbon feed using Y zeolites is investigated. Effect of residual moisture on p-xylene adsorption on BaY was measured in order to optimize the activation temperature of the adsorbent. The results show that with an increase in temperature the moisture on the adsorbent decreases. An optimum loading of moisture is required for adsorption of xylene on the adsorbents. The Everett equation is used to determine the adsorption capacity and selectivity. It has been found that the adsorbents best suited for the separation of p-xylene, m-xylene, o-xylene and ethyl benzene from the mixture of C8 aromatics are NaY, NaY, BaY and KY, respectively. The XRD results show that the crystallinity of the adsorbent decreases upon exchanging the zeolites to K+ and Ba2+ ions.

  2. High-temperature rate constant measurements for OH+xylenes

    KAUST Repository

    Elwardani, Ahmed Elsaid

    2015-06-01

    The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k 1), m-xylene (k 2), and p-xylene (k 3) were measured behind reflected shock waves over 890-1406K at pressures of 1.3-1.8atm using OH laser absorption near 306.7nm. Measurements were performed under pseudo-first-order conditions. The measured rate constants, inferred using a mechanism-fitting approach, can be expressed in Arrhenius form as:k1=2.93×1013exp(-1350.3/T)cm3mol-1s-1(890-1406K)k2=3.49×1013exp(-1449.3/T)cm3mol-1s-1(906-1391K)k3=3.5×1013exp(-1407.5/T)cm3mol-1s-1(908-1383K)This paper presents, to our knowledge, first high-temperature measurements of the rate constants of the reactions of xylene isomers with OH radicals. Low-temperature rate-constant measurements by Nicovich et al. (1981) were combined with the measurements in this study to obtain the following Arrhenius expressions, which are applicable over a wider temperature range:k1=2.64×1013exp(-1181.5/T)cm3mol-1s-1(508-1406K)k2=3.05×109exp(-400/T)cm3mol-1s-1(508-1391K)k3=3.0×109exp(-440/T)cm3mol-1s-1(526-1383K) © 2015 The Combustion Institute.

  3. Polyhedral Oligomeric Silsesquioxane (POSS) Styrene Macromers

    National Research Council Canada - National Science Library

    Haddad, Timothy

    2001-01-01

    .... Cyclohexyl, cyclopentyl and isobutyl substituted POSS-stryenes (at 30 weight % loadings) undergo free radical bulk polymerizations with styrene to produce polymers with an enhanced modulus above the glass transition temperature...

  4. Radiation-induced grafting of styrene on polypropylene pellets

    International Nuclear Information System (INIS)

    Souza, Camila P.; Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.

    2009-01-01

    The changes of radiation-induced in polypropylene (PP) pellets exposed to gamma irradiation in inert atmosphere were investigated in correlation with the applied doses (10 and 50 kGy). Also, results from the grafting of styrene onto PP pellets using simultaneous irradiation at the same doses are presented. The grafting reaction was carried out using toluene as solvent, under nitrogen atmosphere and at room temperature. The properties of the irradiated and grafted PP pellets were studied using Melt Flow Index, thermal analysis (TG and DSC), and ATR-IR. The degree of grafting (DOG) for the grafted pellets was gravimetrically determined. The results showed that radiation-induced graft polymerization on pellets were successfully obtained and the influence of dose irradiated did not change the thermal properties in spite of the increase in the MFI and consequently this increase in the viscosity results an decrease the molecular mass. The MFI for grafted pellets was not achievable because the high degree of viscosity of polymer, even arising the test temperature, the polymer was not flow enough. (author)

  5. Experimental and kinetic modeling investigation of rich premixed toluene flames doped with n-butanol.

    Science.gov (United States)

    Li, Yuyang; Yuan, Wenhao; Li, Tianyu; Li, Wei; Yang, Jiuzhong; Qi, Fei

    2018-02-09

    n-Butanol is a promising renewable biofuel and has a lot of advantages as a gasoline additive compared with ethanol. Though the combustion of pure n-butanol has been extensively investigated, the chemical structures of large hydrocarbons doped with n-butanol, especially for aromatic fuels, are still insufficiently understood. In this work, rich premixed toluene/n-butanol/oxygen/argon flames were investigated at 30 Torr with synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The blending ratio of n-butanol was varied from 0 to 50%, while the equivalence ratio was maintained at a quite rich value (1.75) for the purpose of studying the influence of n-butanol on the aromatic growth process. Flame species including radicals, reactive molecules, isomers and polycyclic aromatic hydrocarbons (PAHs) were identified and their mole fraction profiles were measured. A kinetic model of toluene/n-butanol combustion was developed from our recently reported toluene and n-butanol models. It is observed that the production of most toluene decomposition products and larger aromatics was suppressed as the blending ratio of n-butanol increases. Meanwhile, the addition of n-butanol generally enhanced the formation of most observed C 2 -C 4 hydrocarbons and C 1 -C 4 oxygenated species. The rate of production (ROP) analysis and experimental observations both indicate that the interaction between toluene and n-butanol in their decomposition processes mainly occurs at the formation of small intermediates, e.g. acetylene and methyl. In particular, the interaction between toluene and n-butanol in methyl formation influences the formation of large monocyclic aromatics such as ethylbenzene, styrene and phenylacetylene, making their maximum mole fractions decay slowly upon increasing the blending ratio of n-butanol compared with toluene and benzyl. The increase of the blending ratio of n-butanol reduces the formation of key PAH precursors such as benzyl, fulvenallenyl

  6. Atmospheric oxidation mechanism of toluene.

    Science.gov (United States)

    Wu, Runrun; Pan, Shanshan; Li, Yun; Wang, Liming

    2014-06-26

    The atmospheric oxidation mechanism of toluene initiated by OH radical addition is investigated by quantum chemistry calculations at M06-2X, G3MP2-RAD, and ROCBS-QB3 levels and by kinetics calculation by using transition state theory and unimolecular reaction theory coupled with master equation (RRKM-ME). The predicted branching ratios are 0.15, 0.59, 0.05, and 0.14 for OH additions to ipso, ortho, meta, and para positions (forming R1-R4 adducts), respectively. The fate of R2, R4, and R1 is investigated in detail. In the atmosphere, R2 reacts with O2 either by irreversible H-abstraction to form o-cresol (36%), or by reversible recombination to R2-1OO-syn and R2-3OO-syn, which subsequently cyclize to bicyclic radical R2-13OO-syn (64%). Similarly, R4 reacts with O2 with branching ratios of 61% for p-cresol and 39% for R4-35OO-syn, while reaction of R1 and O2 leads to R1-26OO-syn. RRKM-ME calculations show that the reactions of R2/R4 with O2 have reached their high-pressure limits at 760 Torr and the formation of R2-16O-3O-s is only important at low pressure, i.e., 5.4% at 100 Torr. The bicyclic radicals (R2-13OO-syn, R4-35OO-syn, and R1-26OO-syn) will recombine with O2 to produce bicyclic alkoxy radicals after reacting with NO. The bicyclic alkoxy radicals would break the ring to form products methylglyoxal/glyoxal (MGLY/GLY) and their corresponding coproducts butenedial/methyl-substituted butenedial as proposed in earlier studies. However, a new reaction pathway is found for the bicyclic alkoxy radicals, leading to products MGLY/GLY and 2,3-epoxybutandial/2-methyl-2,3-epoxybutandial. A new mechanism is proposed for the atmospheric oxidation mechanism of toluene based on current theoretical and previous theoretical and experimental results. The new mechanism predicts much lower yield of GLY and much higher yield of butenedial than other atmospheric models and recent experimental measurements. The new mechanism calls for detection of proposed products 2

  7. Primary atmospheric oxidation mechanism for toluene.

    Science.gov (United States)

    Baltaretu, Cristian O; Lichtman, Eben I; Hadler, Amelia B; Elrod, Matthew J

    2009-01-08

    The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique at temperatures ranging from 228 to 298 K. A major dienedial-producing pathway was detected for the first time for toluene oxidation, and glyoxal and methylglyoxal were found to be minor primary oxidation products. The results suggest that secondary oxidation processes involving dienedial and epoxide primary products are likely responsible for previous observations of glyoxal and methylglyoxal products from toluene oxidation. Because the dienedial-producing pathway is a null cycle for tropospheric ozone production and glyoxal and methylglyoxal are important secondary organic aerosol precursors, these new findings have important implications for the modeling of toluene oxidation in the atmosphere.

  8. Health assessment of toluene in California drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Reed, N.; Reed, W.; Beltran, L.; Li, R.; Encomienda, I.

    1989-03-08

    This report reviews existing literature pertinent to the health risk posed by the use of toluene-contaminated drinking water. Also included in the study is an estimate of the toluene exposure of California residents based on the most recent data on toluene concentrations in California drinking water supplies. The concentration of toluene in drinking water that may cause adverse health effects is delineated.

  9. Mobility of Toluene in Polystyrene-Toluene Solutions: A NMR Study

    Science.gov (United States)

    1992-07-01

    FDB-25 Mobility of Toluene in Polystyrene-Toluene Solutions. A NMR Study. by Byaprorn naNagara, Robert D. O’Connor, and Frank D. Blum Department of...NUMBERS Mobility of Toluene in Polystyrene-Toluene Solutions. A NMR Study N00014-91-J-1274 6. AUTHOR(S) Byaporn naNagara, Robert D. O’Connor, Frank D. Blun... Stejskal and Tanner 26 yields an echo amplitude which is given by:4 ,5,26 ,27 X 2-2, 2) A = Ao f(A) ex _(-4- - (y8G) D(A-8/3) where A denotes the

  10. Biodiesel production from wet municipal sludge: evaluation of in situ transesterification using xylene as a cosolvent.

    Science.gov (United States)

    Choi, O K; Song, J S; Cha, D K; Lee, J W

    2014-08-01

    This study proposes a method to produce biodiesel from wet wastewater sludge. Xylene was used as an alternative cosolvent to hexane for transesterification in order to enhance the biodiesel yield from wet wastewater sludge. The water present in the sludge could be separated during transesterification by employing xylene, which has a higher boiling point than water. Xylene enhanced the biodiesel yield up to 8.12%, which was 2.5 times higher than hexane. It was comparable to the maximum biodiesel yield of 9.68% obtained from dried sludge. Xylene could reduce either the reaction time or methanol consumption, when compared to hexane for a similar yield. The fatty acid methyl esters (FAMEs) content of the biodiesel increased approximately two fold by changing the cosolvent from hexane to xylene. The transesterification method using xylene as a cosolvent can be applied effectively and economically for biodiesel recovery from wet wastewater sludge without drying process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. 21 CFR 177.1810 - Styrene block polymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Styrene block polymers. 177.1810 Section 177.1810... FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1810 Styrene block polymers. The styrene...

  12. Pilot-scale production of (S)-styrene oxide from styrene by recombinant Escherichia coli synthesizing styrene monooxygenase.

    Science.gov (United States)

    Panke, Sven; Held, Martin; Wubbolts, Marcel G; Witholt, Bernard; Schmid, Andreas

    2002-10-05

    Recombinant Escherichia coli JM101(pSPZ10) cells produce the styrene monooxygenase of Pseudomonas sp. strain VLB120, which catalyzes the oxidation of styrene to (S)-styrene oxide at an enantiomeric excess larger than 99%. This biocatalyst was used to produce 388 g of styrene oxide in a two-liquid phase 30-L fed-batch bioconversion. The average overall volumetric activity was 170 U per liter over a period of more than 10 h, equivalent to mass transfer rates of 10.2 mmoles per liter per hour at a phase ratio of 0.5. At this transfer rate, the biotransformation system appeared to be substrate mass-transfer limited. The reactor had an estimated power input in the order of 5 W. L(-1), which is close to values typically obtained with commercially operating units. The product could be easily purified by fractional distillation to a purity in excess of 97%. The process illustrates the feasibility of recombinant whole cell biotransformations in two-liquid phase systems with toxic substrates and products. Copyright 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 33-41, 2002.

  13. RAFT Polymerization of Styrene and Maleimide in the Presence of Fluoroalcohol: Hydrogen Bonding Effects with Classical Alternating Copolymerization as Reference

    Directory of Open Access Journals (Sweden)

    Fangjun Yao

    2017-03-01

    Full Text Available The impacts of hydrogen bonding on polymerization behavior has been of interest for a long time; however, universality and in-depth understanding are still lacking. For the first time, the effect of hydrogen bonding on the classical alternating-type copolymerization of styrene and maleimide was explored. N-phenylmaleimide (N-PMI/styrene was chosen as a model monomer pair in the presence of hydrogen bonding donor solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP, which interacted with N-PMI via hydrogen bonding. Reversible addition-fragmentation chain transfer polymerization (RAFT technique was used to guarantee the “living” polymerization and thus the homogeneity of chain compositions. In comparison with the polymerization in nonhydrogen bonding donor solvent (toluene, the copolymerization in HFIP exhibited a high rate and a slight deviation from alternating copolymerization tendency. The reactivity ratios of N-PMI and St were revealed to be 0.078 and 0.068, respectively, while the reactivity ratios in toluene were 0.026 and 0.050. These interesting results were reasonably explained by using computer simulations, wherein the steric repulsion and electron induction by the hydrogen bonding between HFIP and NPMI were revealed. This work first elucidated the hydrogen bonding interaction in the classical alternating-type copolymerization, which will enrich the research on hydrogen bonding-induced polymerizations.

  14. Kinetics modeling of ethylbenzene dehydrogenation to styrene over a mesoporous alumina supported iron catalyst

    KAUST Repository

    Hossain, Mohammad M.

    2012-10-01

    The kinetics of ethylbenzene (EB) dehydrogenation over a FeO x-meso-Al 2O 3 catalyst is studied. The models were developed based on physicochemical characterization and a CREC fluidized Riser Simulator data. N 2 adsorption shows that the synthesized FeO x-meso-Al 2O 3 catalyst is mesoporous with pore size between 9 and 35nm. TPR profile indicates that iron on meso-Al 2O 3 forms easily reducible nanostructured crystals which is confirmed by TEM image. NH 3- and CO-TPD analysis, respectively reveals the availability of both acidic and basic sites. The dehydrogenation of ethylbenzene on FeO x-meso-Al 2O 3 catalyst mainly gives styrene (∼99%) while a small amount of benzene, toluene and coke are also detected. Based on the experimental observations two Langmuir-Hinshelwood type kinetics models are formulated. The possible catalyst deactivation is expressed as function of EB conversion. Parameters are estimated by fitting of the experimental data implemented in MATLAB. Results show that one type site Langmuir-Hinshelwood model appropriately describes the experimental data, with adequate statistical fitting indicators and also satisfied the physical constraints. The activation energy for the formation of styrene (80kJ/mol) found to be significantly lower than that of the undesired products benzene (144kJ/mol) and toluene (164kJ/mol). The estimated heat of adsorptions of EB and ST are found to be 55kJ/mol and 19kJ/mol, respectively. © 2012 Elsevier B.V.

  15. Membrane Materials and Technology for Xylene Isomers Separation and Isomerization via Pervaporation

    KAUST Repository

    Bilaus, Rakan

    2014-11-01

    P-xylene is one of the highly influential commodities in the petrochemical industry. It is used to make 90% of the world’s third largest plastic production, polyethylene terephthalate (PET). With a continuously increasing demand, the current technology’s high energy intensity has become a growing concern. Membrane separation technology is a potential low-energy alternative. Polymeric membranes were investigated in a pervaporation experiment to separate xylene isomers. Polymers of intrinsic microporosity (PIMs) as well as polyimides (PIM-PI), including thermally cross-linked PIM-1, PIM-6FDA-OH and thermally-rearranged PIM-6FDA-OH were investigated as potential candidates. Although they exhibited extremely high permeability to xylenes, selectivity towards p-xylene was poor. This was attributed to the polymers low chemical resistance which was apparent in their strong tendency to swell in xylenes. Consequently, a perfluoro-polymer, Teflon AF 2400, with a high chemical resistance was tested, which resulted in a slightly improved selectivity. A super acid sulfonated perfluoro-polymer (Nafion-H) was used as reactive membrane for xylenes isomerization. The membrane exhibited high catalytic activity, resulting in 19.5% p-xylene yield at 75ᵒC compared to 20% p-xylene yield at 450ᵒC in commercial fixed bed reactors. Nafion-H membrane outperforms the commercial technology with significant energy savings.

  16. Highly enriched Betaproteobacteria growing anaerobically with p-xylene and nitrate

    DEFF Research Database (Denmark)

    Rotaru, Amelia-Elena; Probian, Christina; Wilkes, Heinz

    2010-01-01

    The identity of the microorganisms capable of anaerobic p-xylene degradation under denitrifying conditions is hitherto unknown. Here, we report highly enriched cultures of freshwater denitrifying bacteria that grow anaerobically with p-xylene as the sole organic carbon source and electron donor. ...

  17. Catalytic dehydrogenations of ethylbenzene to styrene

    NARCIS (Netherlands)

    Nederlof, C.

    2012-01-01

    This research work on the catalytic dehydrogenation of ethylbenzene (EB) to styrene (ST) had a primary goal of developing improved catalysts for dehydrogenation processes both in CO2 as well as with O2 that can compete with the conventional dehydrogenation process in steam. In order to achieve this

  18. Regenerated thermosetting styrene-co-acrylonitrile sandwich ...

    Indian Academy of Sciences (India)

    thermosetting styrene-co-acrylonitrile (SAN) foam scraps via compression moulding for the purpose of recycling waste SAN foam and ... is a typical physical recycling method to recycle thermoset- ting material scraps [3], and its .... dried with absorbent paper and the specimens were weighed using an analytical balance with ...

  19. Helbredsrisici ved eksponering for styren i glasfiberplastindustrien

    DEFF Research Database (Denmark)

    Kolstad, Henrik Albert; Ebbehøj, Nielse; Bonde, Jens Peter

    2012-01-01

    system effects with for instance reduced psychological performance, colour discrimination and hearing level following long-term styrene exposure above 10 ppm. There is moderate evidence of a causal association with cancer, but data are not sufficient to allow us to pinpoint specific cancers at risk...

  20. Styrene metabolism, genotoxicity, an potential carcinogenicity

    Czech Academy of Sciences Publication Activity Database

    Vodička, Pavel; Koskinen, M.; Naccarati, Alessio; Oesch-Bartlomowicz, B.; Vodičková, Ludmila; Hemminki, K.; Oesch, F.

    2006-01-01

    Roč. 38, č. 4 (2006), s. 805-853 ISSN 0360-2532 R&D Projects: GA ČR GA310/03/0437 Institutional research plan: CEZ:AV0Z50390512 Keywords : Styrene * Biotransformation * DNA and chromosomal damage Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.754, year: 2006

  1. Environmental behavior and eco-toxicity of xylene in aquatic environments: A review.

    Science.gov (United States)

    Duan, Weiyan; Meng, Fanping; Wang, Feifei; Liu, Qunqun

    2017-11-01

    With the demand for chemicals and fuels increasing continuously, the occurrence of accidental leakage poses great risks to the aquatic environment. Xylene, a hazardous and noxious substance, has been major concerns with regard to heterogeneity and eco-toxicity towards aquatic organisms. This review focused on the ecotoxicological hazards of m-, o-, and p-xylene, as well as mixed xylene, on aquatic organisms. The mechanism of action of xylenes was also demonstrated in details. The purpose of this review was to further understand transfer and diffusion of toxicity on marine and freshwater organisms of xylene in the aquatic environment. Another aim was to screen sensitive biomarkers which were suitable for ecotoxicological assessment and monitoring in an aquatic system. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Stages of xylene transforming during carbon particle synthesis.

    Science.gov (United States)

    Koprinarov, N; Konstantinova, M

    2012-12-01

    Xylene is one of the materials that could be used for synthesis of different carbon nanoparticles including perfect carbon spheres with diameters of 1 to 8 microm and ellipsoids. Its changes in the course of the pyrolytic process in a hermetically sealed stainless steal container have been examined by stopping the process at different stage of temperature treatment from 100 degrees C to 600 degrees C. The prepared material is in a liquid phase up to 400 degrees C and its relative weight and optical transmittance changes have been measured. The origins of these changes are traced to solid micro and nanoparticles and their morphology, which was studied by Scanning (SEM) and Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Electron Probe X-ray Micro Analysis and Energy Dispersive X-ray Spectrometry (EDS), and Fourier Transform Infrared Spectroscopy (FTIR).

  3. Performance of raw and regenerated multi- and single-walled carbon nanotubes in xylene removal from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Hamidreza Pourzamani

    2012-01-01

    Conclusions: It is concluded that recycled carbon nanotubes on heating for the first time, show a better performance for xylene adsorption than when they are raw. The SWCNT are efficient as xylene adsorbents in an environmental pollution cleanup.

  4. Metal-Organic Frameworks for Resonant-Gravimetric Detection of Trace-Level Xylene Molecules.

    Science.gov (United States)

    Xu, Tao; Xu, Pengcheng; Zheng, Dan; Yu, Haitao; Li, Xinxin

    2016-12-20

    As one of typical VOCs, xylene is seriously harmful to human health. Nowadays, however, there is really lack of portable sensing method to directly detect environmental xylene that has chemical inertness. Especially when the concentration of xylene is lower than the human olfactory threshold of 470 ppb, people are indeed hard to be aware of and avoid this harmful vapor. Herein the metal-organic framework (MOF) of HKUST-1 is first explored for sensing to the nonpolar molecule of p-xylene. And the sensing mechanism is identified that is via host-guest interaction of MOF with xylene molecule. By loading MOFs on mass-gravimetric resonant-cantilevers, sensing experiments for four MOFs of MOF-5, HKUST-1, ZIF-8, and MOF-177 approve that HKUST-1 has the highest sensitivity to p-xylene. The resonant-gravimetric sensing experiments with our HKUST-1 based sensors have demonstrated that trace-level p-xylene of 400 ppb can be detected that is lower than the human olfactory threshold of 470 ppb. We analyze that the specificity of HKUST-1 to xylene comes from Cu 2+ -induced moderate Lewis acidity and the "like dissolves like" interaction of the benzene ring. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is used to elucidate the adsorbing/sensing mechanism of HKUST-1 to p-xylene, where p-xylene adsorbing induced blue-shift phenomenon is observed that confirms the sensing mechanism. Our study also indicates that the sensor shows good selectivity to various kinds of common interfering gases. And the long-term repeatability and stability of the sensing material are also approved for the usage/storage period of two months. This research approves that the MOF materials exhibit potential usages for high performance chemical sensors applications.

  5. Human response to varying concentrations of toluene

    DEFF Research Database (Denmark)

    Bælum, Jesper; Lundqvist, G R; Mølhave, Lars

    1990-01-01

    Thirty two males and 39 females aged 31-50 were exposed for 7 h to one of the three following conditions: (1) Clean air, (2) constant exposure to 100 ppm toluene, or (3) a varying exposure with the same time-weighted average, but with peaks of 300 ppm every 30 min. During exposure the subjects ex...

  6. Chromatographic Determination of Toluene and its Metabolites in Urine for Toluene Exposure - A Review

    International Nuclear Information System (INIS)

    Mohamad Raizul Zinalibdin; Abdul Rahim Yacob; Mohd Marsin Sanagi

    2016-01-01

    The determinations of toluene and their metabolites in biological samples such as urine and blood allow the estimation of the degree of exposure to this chemical. Chromatographic methods and preliminary methods are now universally employed for this purpose. Preliminary color test methods are well established for qualitative determination of toluene and its metabolites. Mobile test kits using color test methods are a vast tool for screening urine samples but chromatographic methods are still needed for confirmation and quantitative analysis. Gas chromatography (GC) methods are well-adapted for the determination of toluene metabolite in urine, but these methods often require several pretreatment steps. Meanwhile, high performance liquid chromatography (HPLC) is becoming a powerful tool for the accurate and easy determination of toluene metabolites considering its decisive advantages for routine monitoring. Furthermore, recent development in HPLC could widen the usefulness of this method to solve the most complex analytical problems that could be encountered during the measurement. (author)

  7. Study of the thermal properties of Acrylonitrile Butadiene Styrene - High Impact Polystyrene blends with Styrene Ethylene Butylene Styrene

    OpenAIRE

    Peydro Rasero, Miguel Ángel; Juárez Varón, David; Sánchez Caballero, Samuel; Parres, F.

    2013-01-01

    A binary blend Acrylonitrile Butadiene Styrene ¿ High Impact Polystyrene (ABS-HIPS 50% wt) was prepared on a twin-screw extruder at 190-210 oC. The different properties were then analyzed using melt flow index (MFI), thermogravimetric analysis (TGA), and Fourier Transform Infrared spectroscopy (FTIR). FTIR analysis indicated heterogeneous distribution of the blend in injected pieces and SEM micrographs show heterogeneous distribution of both phase (ABS and HIPS). On the other hand, we have pr...

  8. Influence of styrene-ethylene-butylene-styrene on the properties of acrylonitrile butadiene styrene-high-impact polystyrene blends

    OpenAIRE

    Peydró Rasero, Miguel Ángel; Parres García, Francisco José; Navarro Vidal, Raúl; Crespo Amorós, José Enrique

    2015-01-01

    A binary blend of acrylonitrile butadiene styrene-high-impact polystyrene (ABS-HIPS 50% wt) was prepared on a twin-screw extruder at 190-210 degrees C. The different properties were then analyzed using tensile strength and impact tests, melt flow index, thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR). The analysis of mechanical properties showed a decrease in elongation at break and impact strength. FTIR analysis indicated heterogeneous distribution of the blend...

  9. The Genome of the Toluene-Degrading Pseudomonas veronii Strain 1YdBTEX2 and Its Differential Gene Expression in Contaminated Sand.

    Directory of Open Access Journals (Sweden)

    Marian Morales

    Full Text Available The natural restoration of soils polluted by aromatic hydrocarbons such as benzene, toluene, ethylbenzene and m- and p-xylene (BTEX may be accelerated by inoculation of specific biodegraders (bioaugmentation. Bioaugmentation mainly involves introducing bacteria that deploy their metabolic properties and adaptation potential to survive and propagate in the contaminated environment by degrading the pollutant. In order to better understand the adaptive response of cells during a transition to contaminated material, we analyzed here the genome and short-term (1 h changes in genome-wide gene expression of the BTEX-degrading bacterium Pseudomonas veronii 1YdBTEX2 in non-sterile soil and liquid medium, both in presence or absence of toluene. We obtained a gapless genome sequence of P. veronii 1YdBTEX2 covering three individual replicons with a total size of 8 Mb, two of which are largely unrelated to current known bacterial replicons. One-hour exposure to toluene, both in soil and liquid, triggered massive transcription (up to 208-fold induction of multiple gene clusters, such as toluene degradation pathway(s, chemotaxis and toluene efflux pumps. This clearly underlines their key role in the adaptive response to toluene. In comparison to liquid medium, cells in soil drastically changed expression of genes involved in membrane functioning (e.g., lipid composition, lipid metabolism, cell fatty acid synthesis, osmotic stress response (e.g., polyamine or trehalose synthesis, uptake of potassium and putrescine metabolism, highlighting the immediate response mechanisms of P. veronii 1YdBTEX2 for successful establishment in polluted soil.

  10. Hepatic metabolism of toluene after gastrointestinal uptake in humans

    DEFF Research Database (Denmark)

    Bælum, Jesper; Mølhave, Lars; Honoré Hansen, S

    1993-01-01

    The metabolism of toluene and the influence of small doses of ethanol were measured in eight male volunteers after gastrointestinal uptake, the toluene concentration in alveolar air and the urinary excretion of hippuric acid and ortho-cresol being used as the measures of metabolism. During toluene...

  11. Nonionic surfactant Brij35 effects on toluene biodegradation in a ...

    African Journals Online (AJOL)

    Nonionic surfactant effects on the toluene dissolved in the water phase and biodegradation kinetic behaviors of toluene in a composite bead biofilter were investigated. The toluene dissolved in the water phase was enhanced by the addition of surfactant into aqueous solution and the enhancing effect was more pronounced ...

  12. Biodegradation and growth characteristics of a toluene-degrading ...

    African Journals Online (AJOL)

    A toluene-degrading strain was isolated from active sludge in this study. Both growth characteristic and the performance to degrade toluene by the strain in batch culture mode were evaluated. Results showed that the isolated strain presented a good ability to remove toluene with the maximum removal efficiency of 93.8%.

  13. Evaluation of the Dermal Bioavailability of Aqueous Xylene in F344 Rats and Human Volunteers

    Energy Technology Data Exchange (ETDEWEB)

    Thrall, Karla D.(BATTELLE (PACIFIC NW LAB)); Woodstock, Angie D.(BATTELLE (PACIFIC NW LAB))

    2003-07-11

    Xylene is a clear, colorless liquid used as a solvent in the printing, rubber, and leather industries and is commonly found in paint thinners, paints, varnishes, and adhesives. Although humans are most likely to be exposed to xylene via inhalation, xylene is also found in well and surface water. Therefore, an assessment of the dermal contribution to total xylene uptake is useful for understanding human exposures. To evaluate the significance of these exposures, the dermal absorption of o-xylene was assessed in F344 male rats and human volunteers using a combination of real-time exhaled breath analysis and physiologically based pharmacokinetic (PBPK) modeling. Animals were exposed to o-xylene dermally. Immediately following the initiation of exposure, individual animals were placed in a glass off-gassing chamber and exhaled breath was monitored. Human volunteers participating in the study placed both legs into a stainless steel hydrotherapy tub containing an initial concentration of approximately 500 g/L o-xylene. Exhaled breath was continually analyzed from each volunteer before, during, and post-exposure to track absorption and subsequent elimination of the compound in real time. In both animal and human studies, a PBPK model was used to estimate the dermal permeability coefficient (Kp) to describe each set of exhaled breath data. Rat skin was found to be approximately 12 times more permeable to aqueous o-xylene than human skin. The estimated human and rat aqueous o-xylene Kp values were 0.005+/- 0.001 cm/hr and 0.058+/- 0.009 cm/hr, respectively.

  14. Preirradiation Graft Polymerization of Styrene in a Poly(tetrafluoroethylene Film Investigated by Time-Resolved Small-Angle Neutron Scattering

    Directory of Open Access Journals (Sweden)

    Hiroki Iwase

    2011-01-01

    Full Text Available Preirradiation graft polymerization of styrene in a poly(tetrafluoroethylene (PTFE film was examined by time-resolved small-angle neutron scattering (SANS. A crosslinked PTFE film, thickness of which is about 50 μm, was irradiated by γ-ray and immersed in a mixed solvent of styrene monomer and toluene. SANS elucidated that graft polymerization proceeds by two reaction processes (I and (II. In process (I at 0<<200 min, graft polymerization occurs at an interface between crystalline and amorphous PTFE domains and the grafted polystyrene segregates from PTFE, forming a thin layer with a sharp interface. In process (II at 200<<600 min, grafted PS layer starts to bridge between crystalline domains. At the end of process (II, 40% of total crystalline PTFE domain is covered by the grafted PS chains.

  15. Styrene-Based Copolymer for Polymer Membrane Modifications

    OpenAIRE

    Harsha Srivastava; Harshad Lade; Diby Paul; G. Arthanareeswaran; Ji Hyang Kweon

    2016-01-01

    Poly(vinylidene fluoride) (PVDF) was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffr...

  16. Copper-catalyzed radical carbooxygenation: alkylation and alkoxylation of styrenes.

    Science.gov (United States)

    Liao, Zhixiong; Yi, Hong; Li, Zheng; Fan, Chao; Zhang, Xu; Liu, Jie; Deng, Zixin; Lei, Aiwen

    2015-01-01

    A simple copper-catalyzed direct radical carbooxygenation of styrenes is developed utilizing alkyl bromides as radical resources. This catalytic radical difunctionalization accomplishes both alkylation and alkoxylation of styrenes in one pot. A broad range of styrenes and alcohols are well tolerated in this transformation. The EPR experiment shows that alkyl halides could oxidize Cu(I) to Cu(II) in this transformation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups

    OpenAIRE

    Branislav Husár; Norbert Moszner; Ivan Lukáč

    2012-01-01

    (±)-10-Methacryloyloxycamphorquinone (MCQ) was synthesized from (±)-10-camphorsulfonic acid either by a known seven-step synthetic route or by a novel, shorter five-step synthetic route. MCQ was copolymerized with styrene (S) and the photochemical behavior of the copolymer MCQ/S was compared with that of a formerly studied copolymer of styrene with monomers containing the benzil (BZ) moiety (another 1,2-dicarbonyl). Irradiation (λ > 380 nm) of aerated films of styrene copolymer...

  18. High-pressure transformations of ortho-xylene probed by combined infrared and Raman spectroscopies

    Science.gov (United States)

    Bai, Yanzhi; Li, Nana; Pei, Cuiying; Yan, Zhipeng; Li, Wentao; Wei, Dongqing

    2018-01-01

    Here, we report high-pressure investigations of ortho-xylene (o-xylene) using combined infrared (IR) and Raman spectral measurements at room temperature and pressures up to 32.1 GPa, respectively. Liquid o-xylene visually crystallized at around 0.4 GPa. Upon compression, the spectra changed; including splitting, disappearing, broadening of modes, and the appearance of new modes. We found four more phase transitions in o-xylene to phases III, IV, V, and VI at around 1.4, 3.9, 12.3, and 16.8 GPa, respectively. The final product recovered from over 20 GPa was preserved at ambient conditions and the mass spectrometry experiment indicated phase transition are polymerization.

  19. The effect of ageing and in vitro exposure to xylene and KCl on [Ca2+](i) in synaptosomes from rats exposed prenatally to xylene

    DEFF Research Database (Denmark)

    Edelfors, S.; Hass, Ulla; Ravn-Jonsen, A.

    1996-01-01

    Female rats (Mol:WIST) were exposed prenatally to 500 p.p.m, of technical xylene on days 7-20. At the age of fourteen months the rats were sacrified and the synaptosomal fraction prepared for in vivo studies. The cytosolic calcium concentration was measured using the FURA-2 technique. The cytosolic...... calcium was increased in synaptosomes from old rats compared to those from rats at the age of three months, but no effect of prenatal exposure was seen. When synaptosomes were incubated with xylene, potassium or both, the cytosolic calcium concentration was changed identically in all groups of rats. When...

  20. Effects of prenatal exposure to xylene on postnatal development and behavior in rats

    DEFF Research Database (Denmark)

    Hass, Ulla; Lund, S. P.; Simonsen, L.

    1995-01-01

    The effects of prenatal exposure to the organic solvent xylene (dimethylbenzene, GAS-no 1330-20-7) on postnatal development and behavior in rats were studied. Pregnant rats (Mol:WIST) were exposed to 500 ppm technical xylene 6 h per day on gestation days 7-20. The dose level was selected so as no......) were found. Generally, the effects were most marked in the female offspring....

  1. Subacute ethanol consumption reverses p-xylene-induced decreases in axonal transport

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, S.; Lyerly, D.L.; Pope, C.N.

    1992-01-01

    Organic solvants, as a class, have been implicated as neurotoxic agents in humans and laboratory animals. The study was designed to assess the interaction between subacute ingestion of moderate levels of ethanol and the p-xylene-induced decreases in protein and glycoprotein synthesis and axonal transport in the rat optic system. The results indicated that animals maintained on 10% ethanol as a drinking liquid show less p-xylene-induced neurotoxicity than animals receiving no ethanol supplement.

  2. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    Directory of Open Access Journals (Sweden)

    OLIVIA ANCA RUSU

    2011-03-01

    Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 μg/m³. Health assessment of a group of 49 workers was based on questionnaire interview, determination of TDI antibodies and lung function tests. Data collected until this stage do not show any negative effects of TDI on the employees health. Since this plant had only recently begun operating, continuous workplace and ambient air TDI monitoring, along with workers health surveillance, is deemed necessary.

  3. Reassessing the atmospheric oxidation mechanism of toluene

    Science.gov (United States)

    Ji, Yuemeng; Zhao, Jun; Terazono, Hajime; Misawa, Kentaro; Levitt, Nicholas P.; Li, Yixin; Lin, Yun; Peng, Jianfei; Wang, Yuan; Duan, Lian; Pan, Bowen; Zhang, Fang; Feng, Xidan; An, Taicheng; Marrero-Ortiz, Wilmarie; Secrest, Jeremiah; Zhang, Annie L.; Shibuya, Kazuhiko; Molina, Mario J.; Zhang, Renyi

    2017-08-01

    Photochemical oxidation of aromatic hydrocarbons leads to tropospheric ozone and secondary organic aerosol (SOA) formation, with profound implications for air quality, human health, and climate. Toluene is the most abundant aromatic compound under urban environments, but its detailed chemical oxidation mechanism remains uncertain. From combined laboratory experiments and quantum chemical calculations, we show a toluene oxidation mechanism that is different from the one adopted in current atmospheric models. Our experimental work indicates a larger-than-expected branching ratio for cresols, but a negligible formation of ring-opening products (e.g., methylglyoxal). Quantum chemical calculations also demonstrate that cresols are much more stable than their corresponding peroxy radicals, and, for the most favorable OH (ortho) addition, the pathway of H extraction by O2 to form the cresol proceeds with a smaller barrier than O2 addition to form the peroxy radical. Our results reveal that phenolic (rather than peroxy radical) formation represents the dominant pathway for toluene oxidation, highlighting the necessity to reassess its role in ozone and SOA formation in the atmosphere.

  4. Reassessing the atmospheric oxidation mechanism of toluene.

    Science.gov (United States)

    Ji, Yuemeng; Zhao, Jun; Terazono, Hajime; Misawa, Kentaro; Levitt, Nicholas P; Li, Yixin; Lin, Yun; Peng, Jianfei; Wang, Yuan; Duan, Lian; Pan, Bowen; Zhang, Fang; Feng, Xidan; An, Taicheng; Marrero-Ortiz, Wilmarie; Secrest, Jeremiah; Zhang, Annie L; Shibuya, Kazuhiko; Molina, Mario J; Zhang, Renyi

    2017-08-01

    Photochemical oxidation of aromatic hydrocarbons leads to tropospheric ozone and secondary organic aerosol (SOA) formation, with profound implications for air quality, human health, and climate. Toluene is the most abundant aromatic compound under urban environments, but its detailed chemical oxidation mechanism remains uncertain. From combined laboratory experiments and quantum chemical calculations, we show a toluene oxidation mechanism that is different from the one adopted in current atmospheric models. Our experimental work indicates a larger-than-expected branching ratio for cresols, but a negligible formation of ring-opening products (e.g., methylglyoxal). Quantum chemical calculations also demonstrate that cresols are much more stable than their corresponding peroxy radicals, and, for the most favorable OH ( ortho ) addition, the pathway of H extraction by O 2 to form the cresol proceeds with a smaller barrier than O 2 addition to form the peroxy radical. Our results reveal that phenolic (rather than peroxy radical) formation represents the dominant pathway for toluene oxidation, highlighting the necessity to reassess its role in ozone and SOA formation in the atmosphere.

  5. Morphology and Phase Transitions in Styrene-Butadiene-Styrene Triblock Copolymer Grafted with Isobutyl Substituted Polyhedral Oligomeric Silsesquioxanes (Postprint)

    National Research Council Canada - National Science Library

    Drazowski, Daniel B; Lee, Andre; Haddad, Timothy S

    2007-01-01

    Two symmetric triblock polystyrene-butadiene-polystyrene (SBS) copolymers with different styrene content were grafted with varying amounts of isobutyl-substituted polyhedral oligomeric silsesquioxane (POSS) molecules...

  6. Morphology and Phase Transitions in Styrene-Butadiene-Styrene Triblock Copolymer Grafted with Isobutyl Substituted Polyhedral Oligomeric Silsesquioxanes (preprint)

    National Research Council Canada - National Science Library

    Drazkowski, Daniel B; Lee, Andre; Haddad, Timothy S

    2006-01-01

    Two symmetric triblock polystyrene-butadiene-polystyrene (SBS) copolymers with different styrene content were grafted with varying amounts of isobutyl-substituted polyhedral oligomeric silsesquioxane (POSS) molecules...

  7. SOA formation from photooxidation of naphthalene and methylnaphthalenes with m-xylene and surrogate mixtures

    Science.gov (United States)

    Chen, Chia-Li; Li, Lijie; Tang, Ping; Cocker, David R.

    2018-05-01

    SOA formation is not well predicted in current models in urban area. The interaction among multiple anthropogenic volatile organic compounds is essential for the SOA formation in the complex urban atmosphere. Secondary organic aerosol (SOA) from the photooxidation of naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene as well as individual polycyclic aromatic hydrocarbons (PAHs) mixed with m-xylene or an atmospheric surrogate mixture was explored in the UCR CE-CERT environmental chamber under urban relevant low NOx and extremely low NOx (H2O2) conditions. Addition of m-xylene suppressed SOA formation from the individual PAH precursor. A similar suppression effect on SOA formation was observed during the surrogate mixture photooxidation suggesting the importance of gas-phase chemical reactivity to SOA formation. The SOA growth rate for different PAH-m-xylene mixtures was strongly correlated with initial [HO2]/[RO2] ratio but negatively correlated with initial m-xylene/NO ratio. Decreasing SOA formation was observed for increasing m-xylene/PAHs ratios and increasing initial m-xylene/NO ratio. The SOA chemical composition characteristics such as f44 versus f43, H/C ratio, O/C ratio, and the oxidation state of the carbon OSbarc were consistent with a continuously aging with the SOA exhibiting characteristics of both individual precursors. SOA formation from PAHs was also suppressed within an atmospheric surrogate mixture compared to the SOA formed from individual PAHs, indicating that atmospheric reactivity directly influences SOA formation from PAHs.

  8. 40 CFR 721.10151 - Modified styrene, divinylbenzene polymer (generic).

    Science.gov (United States)

    2010-07-01

    ... polymer (generic). 721.10151 Section 721.10151 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10151 Modified styrene, divinylbenzene polymer (generic). (a) Chemical... as modified styrene, divinylbenzene polymer (PMN P-07-642) is subject to reporting under this section...

  9. Sex differences in the toxicokinetics of inhaled solvent vaporsin humans 1. m-Xylene

    International Nuclear Information System (INIS)

    Ernstgaard, Lena; Sjoegren, Bengt; Warholm, Margareta; Johanson, Gunnar

    2003-01-01

    The aim of this study was to evaluate possible sex differences in the inhalation toxicokinetics of m-xylene vapor. Seventeen healthy volunteers (nine women and eight men) were exposed to m-xylene (200 mg/m 3 ) and to clean air (control exposure) on different occasions during 2 h of light physical exercise (50 W). The chosen level corresponds to the occupational exposure limit (8-h time weighted average) in Sweden. m-Xylene was monitored up to 24 h after exposure in exhaled air, blood, saliva, and urine by headspace gas chromatography. m-Methylhippuric acid (a metabolite of m-xylene) was analyzed in urine by high-performance liquid chromatography. Body fat and lean body mass (LBM) were estimated from sex-specific equations using bioelectrical impedance, body weight, height, and age. Genotypes and/or phenotypes of cytochromes P450 2E1 and 1A1, glutathione transferases M1 and P1, and epoxide hydrolase were determined. The toxicokinetic profile in blood was analyzed using a two-compartment population model. The area under the concentration-time curve (AUC) of m-xylene in exhaled air postexposure was larger in women than in men. In addition, the excretion via exhaled air was significantly higher in women when correcting for body weight or LBM. In contrast, the men had a significantly higher volume of distribution, excretion of m-methylhippuric acid in urine, and AUC of m-xylene in urine. The toxicokinetic analyses revealed no differences between subjects of different metabolic genotypes or phenotypes. In conclusion, the study indicates small sex differences in the inhalation toxicokinetics of m-xylene, which can be explained by body build

  10. A comparative study on vibrational, conformational and electronic structure of α,α'-diol-o-xylene, α,α'-diol-m-xylene and α,α'-diol-p-xylene

    Science.gov (United States)

    Arjunan, V.; Saravanan, I.; Mythili, C. V.; Kalaivani, M.; Mohan, S.

    2012-06-01

    The Fourier transform infrared (FTIR) and FT-Raman spectra of α,α'-diol-o-xylene (DOLOX), α,α'-diol-m-xylene (DOLMX) and α,α'-diol-p-xylene (DOLPX) of the configuration HOCH2-C6H4-CH2OH have been recorded in the range 4000-400 and 4000-100 cm-1, respectively. The most stable geometry of the compounds was determined by conformational analysis. The complete vibrational assignment and analysis of the fundamental modes of the most stable conformer of the compounds were carried out using the experimental FTIR and FT-Raman data and quantum chemical studies. The observed vibrational frequencies were compared with the wavenumbers derived theoretically for the optimised geometry of the compounds from the DFT-B3LYP gradient calculations employing the standard 6-31G** and high level and 6-311++G** basis sets. The structural parameters and vibrational wavenumbers obtained from the DFT method are in good agreement with the experimental data. The potential energy distributions of the fundamental modes were also calculated by Wilson's FG matrix method. The effect of -CH2OH groups on the skeletal vibrations have been discussed. The intra molecular n → σ* and π → π* interactions were discussed with NBO analysis.

  11. Impact of styrenic polymer one-step hyper-cross-linking on volatile organic compound adsorption and desorption performance.

    Science.gov (United States)

    Ghafari, Mohsen; Atkinson, John D

    2018-06-05

    A novel one-step hyper-cross-linking method, using 1,2-dichloroethane (DCE) and 1,6-dichlorohexane (DCH) cross-linkers, expands the micropore volume of commercial styrenic polymers. Performance of virgin and modified polymers was evaluated by measuring hexane, toluene, and methyl-ethyl-ketone (MEK) adsorption capacity, adsorption/desorption kinetics, and desorption efficiency. Hyper-cross-linked polymers have up to 128% higher adsorption capacity than virgin polymers at P/P 0  = 0.05 due to micropore volume increases up to 330%. Improvements are most pronounced with the DCE cross-linker. Hyper-cross-linking has minimal impact on hexane adsorption kinetics, but adsorption rates for toluene and MEK decrease by 6-41%. Desorption rates decreased (3-36%) for all materials after hyper-cross-linking, with larger decreases for DCE hyper-cross-linked polymers due to smaller average pore widths. For room temperature desorption, 20-220% more adsorbate remains in hyper-cross-linked polymers after regeneration compared to virgin materials. DCE hyper-cross-linked polymers have 13-92% more residual adsorbate than DCH counterparts. Higher temperatures were required for DCE hyper-cross-linked polymers to completely desorb VOCs compared to the DCH hyper-cross-linked and virgin counterparts. Results show that the one-step hyper-cross-linking method for modifying styrenic polymers improves adsorption capacity because of added micropores, but decreases adsorption/desorption kinetics and desorption efficiency for large VOCs due to a decrease in average pore width. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Neuropharmacological and cochleotoxic effects of styrene. Consequences on noise exposures.

    Science.gov (United States)

    Campo, Pierre; Venet, Thomas; Thomas, Aurélie; Cour, Chantal; Brochard, Céline; Cosnier, Frédéric

    2014-01-01

    Occupational noise exposure can damage workers' hearing, particularly when combined with exposure to cochleotoxic chemicals such as styrene. Although styrene-induced cochlear impairments only become apparent after a long incubation period, the pharmacological impact of styrene on the central nervous system (CNS) can be rapidly measured by determining the threshold of the middle-ear acoustic reflex (MER) trigger. The aim of the study was to evaluate the effects of a noise (both continuous and impulse), and a low concentration of styrene [300ppmnoise was lower (80dB SPL sound pressure level) than that of the continuous noise (85dB SPL), it appeared more detrimental to the peripheral auditory receptors. A co-exposure to styrene and continuous noise was less damaging than exposure to continuous noise alone. In contrast, the traumatic effects of impulse noise on the organ of Corti were enhanced by co-exposure to styrene. The pharmacological effects of the solvent on the CNS were discussed to put forward a plausible explanation of these surprising results. We hypothesize that CNS effects of styrene may account for this apparent paradox. Based on the present results, the temporal structure of the noise should be reintroduced as a key parameter in hearing conservation regulations. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Substituent effects in surface-initiated ATRP of substituted styrenes

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sampa, E-mail: ssaha@polymers.iitd.ac.in; Baker, Gregory L.

    2015-12-30

    Graphical abstract: - Highlights: • Suitably substituted styrenes can lead to rapid synthesis of uniform and thick polystyrene brushes (>100 nm in 1 h) from gold surface via surface initiated ATRP. • High growth rates were observed for styrenes substituted with electron withdrawing groups in meta/para positions. • Electron donors at meta sites show surprisingly fast growth rates, which may be due to steric inhibition of termination. • Surface polymerization rates for substituted styrenes followed the Hammett relation with ρ = 0.51, similar to conventional radical polymerization in solution. - Abstract: Surface initiated atom transfer radical polymerization (ATRP) of substituted styrenes leads to rapid synthesis of uniform and thick substituted polystyrene brushes (>100 nm in 1 h) from gold surface. High growth rates were observed for styrenes substituted with electron withdrawing groups in meta/para positions. The effects seen in surface and solution polymerizations are similar for styrenes with electron withdrawing groups, and for electron donors in ortho and para positions. However, electron donors at meta sites have surprisingly fast growth rates, which may be due to steric inhibition of termination. The overall surface polymerization rates for substituted styrenes was analyzed and found to follow the Hammett relation with ρ = 0.51. The ratio of k{sub p} to k{sub t}, is as an indicator of the likelihood that a reaction will reach high degrees of polymerization before termination.

  14. Sulfonated Styrene-(ethylene-co-butylene-styrene/Montmorillonite Clay Nanocomposites: Synthesis, Morphology, and Properties

    Directory of Open Access Journals (Sweden)

    Ganguly Anirban

    2007-01-01

    Full Text Available AbstractSulfonated styrene-(ethylene-butylene-styrene triblock copolymer (SSEBS was synthesized by reaction of acetyl sulfate with SEBS. SSESB-clay nanocomposites were then prepared from hydrophilic Na-montmorillonite (MT and organically (quaternary amine modified hydrophobic nanoclay (OMT at very low loading. SEBS did not show improvement in properties with MT-based nanocomposites. On sulfonation (3 and 6 weight% of SEBS, hydrophilic MT clay-based nanocomposites exhibited better mechanical, dynamic mechanical, and thermal properties, and also controlled water–methanol mixture uptake and permeation and AC resistance. Microstructure determined by X-ray diffraction, atomic force microscopy, and transmission electron microscopy due to better dispersion of MT nanoclay particles and interaction of MT with SSEBS matrix was responsible for this effect. The resulting nanocomposites have potential as proton transfer membranes for Fuel Cell applications.

  15. Evaluation of tri-steps modified styrene-butadiene-styrene block copolymer membrane for wound dressing

    International Nuclear Information System (INIS)

    Yang, Jen Ming; Huang, Huei Tsz

    2012-01-01

    Tri-steps modified styrene-butadiene-styrene block copolymer (SBS) membrane was prepared with epoxidation, ring opening reaction with maleated ionomer and layer-by-layer assembled polyelectrolyte technique. The tri-steps modified SBS membrane was characterized by infrared spectroscopy and X-ray photoelectron spectroscope (XPS). The structures of the modified SBS membranes were identified with methylene blue and azocarmine G. The content of amino group on the surface of the modified membrane was calculated from uptake of an acid dye. The values of the contact angle, water absorption, water vapor transmission rate and the adsorption of fibronectin on the membranes were determined. To evaluate the biocompatibility of the tri-steps modified SBS membrane, the cytotoxicity, antibacterial and growth profile of the cell culture of 3T3 fibroblasts on the membrane were evaluated. The bactericidal activity was found on the modified SBS. From the cell culture of 3T3 fibroblasts on the membrane, it revealed that the cells not only remained viable but also proliferated on the surface of the tri-steps modified SBS membranes. As the membranes are sterile semipermeable with bactericidal activity and transparent allowing wound checks, they can be considered for shallow wound with low exudates. - Highlights: ► Styrene-butadiene-styrene block copolymer (SBS) was modified with tri-steps. ► The tri-steps are epoxidation, ring opening reaction and layer-by-layer assembly. ► Modified SBS membrane for wound dressing is evaluated. ► Membranes are sterile semipermeable with bactericidal activity and transparent. ► Membranes can be considered for shallow wound with low exudates.

  16. Biofiltration of xylene using wood charcoal as the biofilter media under transient and high loading conditions.

    Science.gov (United States)

    Singh, Kiran; Giri, B S; Sahi, Amrita; Geed, S R; Kureel, M K; Singh, Sanjay; Dubey, S K; Rai, B N; Kumar, Surendra; Upadhyay, S N; Singh, R S

    2017-10-01

    The main objective of this study was to evaluate the performance of wood charcoal as biofilter media under transient and high loading condition. Biofiltration of xylene was investigated for 150days in a laboratory scale unit packed with wood charcoal and inoculated with mixed microbial culture at the xylene loading rates ranged from 12 to 553gm -3 h -1 . The kinetic analysis of the xylene revealed absence of substrate inhibition and possibility of achieving higher elimination under optimum condition. The pH, temperature, pressure drop and CO 2 production rate were regularly monitored during the experiments. Throughout experimental period, the removal efficiency (RE) was found to be in the range of 65-98.7% and the maximum elimination capacity (EC) was 405.7gm -3 h -1 . Molecular characterization results show Bacillus sp. as dominating microbial group in the biofilm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. [Investigation of the chain structure and thermal property of xylene solubles of impact polypropylene copolymers].

    Science.gov (United States)

    Luo, Hua-Lin; Zhao, Ying; Wu, Jin-Guang; Wang, Du-Jin

    2012-12-01

    Impact polypropylene copolymers (IPC) are in-situ blends of polypropylene homopolymer and ethylene-alpha-olefin copolymers formed in the reactor, which is a multiphasic complex material with isotactic polypropylene (iPP) as a matrix in which poly(ethylene-alpha-olefin) elastomeric copolymer is finely dispersed, and ethylene-alpha-olefin random copolymer (EPR) acts as an elastomer to improve the impact resistance properties of iPP at room temperature and low temperature. In the present, the content of xylene soluble is used to evaluate the content of EPR rubber phase in IPC. The content, the chain structure, and glass transition temperature (T(g)) of EPR rubber are critical to the toughness of IPC. In the present report, Fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance (NMR) and differential scanning calorimetry(DSC) were utilized to study the comonomer content, chain structure and thermal property of xylene soluble of two IPC prepared by different catalysts. The results indicated that there are small amount of ethylene-propylene segmented copolymers containing short methylene sequence that is crystallizable in the xylene soluble in addition to the ethylene-propylene random copolymers. And the sequence length of crystallizable methylene group of ethylene-propylene segmented copolymers in these two kinds of xylene soluble is different. The random distribution degree of ethylene and propylene monomer in the ethylene-propylene copolymers in these two kinds of xylene soluble is similar. The xylene soluble with lower content of PPP sequence and higher content of ethylene monomer has lower T(g), which will benefit the improvement of impact resistance property of polypropylene.

  18. The role of glutathione and cysteine conjugates in the nephrotoxicity of o-xylene in rats

    Energy Technology Data Exchange (ETDEWEB)

    Morel, G.; Bonnet, P.; Cossec, B.; Morel, S.; Cour, C.; Lambert, A.M.; Roure, M.B.; Brondeau, M.T. [Institut National de Recherche et de Securite, 54 - Vandoeuvre (France)

    1998-09-01

    Moderate nephrotoxicity was induced in male and female rats exposed to o-xylene for 4 h at atmospheric concentrations of {proportional_to}3000 ppm. The xylene in vivo nephrotoxicity resulted in low enzyme leakage from the kidney into the urine. This low leakage was confirmed in 24-h urine by an increase in {gamma}-glutamyltranspeptidase ({gamma}GT), N-acetyl-{beta}-d-glucosaminidase (NAG) and alkaline phosphatase (ALP) activities. Compared to the control, both the 24-h urine output and the glucose excretion increased in male and female rats. These increases were probably a result of damage to the renal proximal tubules. The role of the metabolic pathway of glutathione in the emergence of the renal damage observed with o-xylene was investigated in rats. Recent studies indicate that the metabolic pathway of glutathione may be a bioactivation pathway, which is responsible for nephrotoxic effects with several drugs or chemicals. The renal toxicity of three synthesized o-xylene thio-conjugates was investigated in several groups of female rats. Administration of S-(o-methylbenzyl)glutathione (i.p., 1 mmol/kg), S-(o-methylbenzyl)cysteine (per os, 1 mmol/kg) or N-acetyl-S-(o-methylbenzyl)cysteine (i.p., 0.75 mmol/kg) to female rats did not induce renal toxicity, as monitored by urinary biochemical parameters ({gamma}GT, NAG, ALP, glucose). The data obtained suggest that the glutathione pathway would appear to be only detoxication, and probably does not contribute to the renal toxicity of o-xylene in female rats. Thus, either another metabolic pathway or other intermediate metabolites are probably involved in the nephrotoxic action of o-xylene. (orig.) (orig.) With 2 figs., 1 tab., 23 refs.

  19. Nonionic surfactant Brij35 effects on toluene biodegradation in a ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... behaviors of toluene in a composite bead biofilter were investigated. The toluene dissolved in the water phase was enhanced by the addition of surfactant into aqueous solution and the enhancing effect was more pronounced in the surfactant concentration less than critical micelle concentration. For the.

  20. Toluene removal in a biofilm reactor for waste gas treatment

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Arvin, E.

    1997-01-01

    A lab-scale trickling filter for treatment of toluene-containing waste gas was investigated. The filter performance was investigated for various loads of toluene. Two levels of the gas flow were examined, 322 m d(-1) and 707 m d(-1). The gas inlet concentrations were varied in the range from 0...

  1. Alkylation of toluene with isopropyl alcohol over SAPO-5 catalyst

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Isopropylation of toluene with isopropyl alcohol was studied over the large pore silicon alu- mino phosphate molecular sieves (SAPO-5) with varying Si content. Toluene conversion was found to increase with increase in the Si of the catalysts. The effect of temperature on yields of cymene was studied in the range ...

  2. Cerebellar dysfunction caused by sniffing of toluene-containing thinner

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Y. (Nagoya Univ. School of Medicine, Japan); Hisanaga, N.; Ono, Y.; Ogawa, T.; Hamaguchi, Y.; Okamoto, S.

    1982-01-01

    A 19-year-old man who had sniffed lacquer thinner for 8 months was found to suffer from cerebellar dysfunction and visual disorders. He had blurred vision, dysarthria, nystagmus, slight intention tremor, staggering gait and an abnormal EEG. The thinner contained 68% toluene, 18% ethyl acetate, 9% methyl isobutyl ketone (MIBK), 3% isopropyl alcohol (IPA) and 3% butyl acetate. The concentration of each solvent in the plastic bag used for sniffing was 12,000 ppm toluene, 11,500 ppm ethyl acetate, 6,000 ppm IPA and 2,000 ppm MIBK. Previously reported cerebellar dysfunction due to toluene or toluene-containing solvents are summarized and discussed. Based on these reports and the present case, toluene is presumed to impair function in the order of the vermis,cerebellar hemispheres, and cerebrum, when a relatively high concentration of toluene is inhaled. The effects of organic solvents, especially toluene, on the cerebellum are considered to be very important from the viewpoint of occupational health, since toluene is widely used in industry and many workers are exposed to it.

  3. Laboratory diagnosis of toluene-based inhalants abuse.

    Science.gov (United States)

    Thiesen, Flavia Valladão; Noto, Ana Regina; Barros, Helena M T

    2007-01-01

    Toluene is the main substance contained in products used as inhalants. The frequent abuse of toluene-based inhalants requires the definition of a simple laboratory parameter that allows acute exposure assessment. This study aimed at defining urinary hippuric acid (UHA) levels related to intentional exposure to toluene, and to correlate them to blood toluene concentration (BT). BT and UHA levels were measured in 65 homeless adolescents of Porto Alegre, Brazil. Toluene was detected in 91.9% of the investigated population, who presented BT levels from 0.5 to 83.7 microg/mL. There was good correlation between UHA and BT concentrations (r = 0.78), and in homeless adolescents, UHA levels higher than 3.0 g/g creatinine indicate intentional exposure to toluene. The determination of UHA concentrations can be used as a screening method for the detection of intentional exposure to toluene, but its diagnosis must include BT toluene dosage, as well as circumstantial and clinical evidence.

  4. Active efflux of toluene in a solvent-resistant bacterium.

    OpenAIRE

    Isken, S; de Bont, J A

    1996-01-01

    We investigated the mechanisms behind the organic-solvent resistance of the solvent-tolerant strain Pseudomonas putida S12. By use of 14C-labeled toluene, we obtained evidence that an energy-dependent export system may be responsible for this resistance to toluene.

  5. Effects of prenatal exposure to xylene on postnatal development and behavior in rats

    DEFF Research Database (Denmark)

    Hass, Ulla; Lund, S. P.; Simonsen, L.

    1995-01-01

    The effects of prenatal exposure to the organic solvent xylene (dimethylbenzene, GAS-no 1330-20-7) on postnatal development and behavior in rats were studied. Pregnant rats (Mol:WIST) were exposed to 500 ppm technical xylene 6 h per day on gestation days 7-20. The dose level was selected so...... as not to induce maternal toxicity or decrease the viability of offspring. In the exposed offspring, a delay in the ontogeny of the air righting reflex, a lower absolute brain weight, and impaired performance in behavioral tests for neuromotor abilities (Rotarod) and for learning and memory (Morris water maze...

  6. Toluene inducing acute respiratory failure in a spray paint sniffer.

    Science.gov (United States)

    Peralta, Diego P; Chang, Aymara Y

    2012-01-01

    Toluene, formerly known as toluol, is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent. Like other solvents, toluene is sometimes also used as an inhalant drug for its intoxicating properties. It has potential to cause multiple effects in the body including death. I report a case of a 27-year-old male, chronic spray paint sniffer, who presented with severe generalized muscle weakness and developed acute respiratory failure requiring ventilatory support. Toluene toxicity was confirmed with measurement of hippuric acid of 8.0 g/L (normal <5.0 g/L). Acute respiratory failure is a rare complication of chronic toluene exposure that may be lethal if it is not recognized immediately. To our knowledge, this is the second case of acute respiratory failure due to toluene exposure.

  7. Sustainable hydrogen production from bio-oil model compounds (meta-xylene) and mixtures (1-butanol, meta-xylene and furfural).

    Science.gov (United States)

    Bizkarra, K; Barrio, V L; Arias, P L; Cambra, J F

    2016-09-01

    In the present work m-xylene and an equimolecular mixture of m-xylene, 1-butanol and furfural, all of them bio-oil model compounds, were studied in steam reforming (SR) conditions. Three different nickel catalysts, which showed to be active in 1-butanol SR (Ni/Al2O3, Ni/CeO2-Al2O3 and Ni/La2O3-Al2O3), were tested and compared with thermodynamic equilibrium values. Tests were carried out at temperatures from 800 to 600°C at atmospheric pressure with a steam to carbon ratio (S/C) of 5.0. Despite the different bio-oils fed, the amount of moles going through the catalytic bed was kept constant in order to obtain comparable results. After their use, catalysts were characterized by different techniques and those values were correlated with the activity results. All catalysts were deactivated during the SR of the mixture, mainly by coking. The highest hydrogen yields were obtained with Ni/Al2O3 and Ni/CeO2-Al2O3 catalysts in the SR of m-xylene and SR of the mixture, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. OH-initiated oxidation of toluene. 2. Master equation simulation of toluene oxide isomerization.

    Science.gov (United States)

    Frankcombe, Terry J; Smith, Sean C

    2007-05-17

    In this work we continue our investigation of the toluene-OH-O2 system. We describe master equation modeling of the isomerization of toluene oxide, focusing on the formation of the cresols. A 15 isomer model is used. Simulations of both thermally activated processes and photolysis processes are described. In accord with experiment, it is found that photolysis with a high-energy light source should be expected to give a high yield of the thermal distribution of cresol products (dominated by the para isomer). Photolysis with a low-energy light source, on the other hand, favors formation of the thermally disfavored ortho isomer. Though the 15 isomer system is potentially an excellent test bed for the development of scalable master equation solution methods, existing scalable solution methods were found to fail on this system.

  9. Early Liver and Kidney Dysfunction Associated with Occupational Exposure to Sub-Threshold Limit Value Levels of Benzene, Toluene, and Xylenes in Unleaded Petrol

    Directory of Open Access Journals (Sweden)

    Masoud Neghab

    2015-12-01

    Conclusion: The average exposure of petrol station workers to BTX did not exceed the current threshold limit values (TLVs for these chemicals. However, evidence of subtle, subclinical and prepathologic early liver and kidney dysfunction was evident in exposed individuals.

  10. Validation of a methodology to determine Benzene, Toluene, Ethylbenzene, and Xylenes concentration present in the air and adsorbed in activated charcoal passive samplers by GC/ FID chromatography

    Directory of Open Access Journals (Sweden)

    Mary Luz Gallego-Díez

    2016-01-01

    Full Text Available En este trabajo se presenta la validación del procedimiento analítico que permite determinar las concentraciones de Benceno (B, Tolueno (T, Etilbenceno (E y Xilenos (X, compuestos conocidos como BTEX, presentes en el aire y adsorbidos sobre carbón activado, usando el método de adición de estándar interno (Fluorobenceno para la cuantificación. En el proceso se empleó carbón activado de referencia para la validación y carbón granular (CGC a base de coco para la construcción de los captadores pasivos, empleados en la toma de muestras en exteriores o aire ambiente. El material CGC fue seleccionado a partir de su capacidad de recuperación de BTEX, con un promedio 89,1% para todos los analitos. En la investigación se evaluó la presencia de BTEX en muestras de aire, tomadas en una vía de seis carriles y caracterizada, además, por ser de alto flujo vehicular en la ciudad de Medellín (Antioquia, Colombia. Los captadores empleados, fueron ubicados en pares por punto (en siete franjas transversales de la vía: andenes oriental, central y occidental, y a alturas que oscilaron entre los 2,50 y 3,00 metros a nivel de piso, dentro de una carcasa especial para su protección. El número de estaciones totales fue de veintiuno (21 en un trayecto de 3 km, para un total de 21 muestras recolectadas con tiempos de exposición de 28 días. El procedimiento de desorción de los analitos se realizó con disulfuro de carbono como solvente de extracción y en el análisis cromatográfico de gases se realizó (por triplicado empleando un detector de ionización de llama (FID. Se usó, además, una columna cromatográfica HP- INNOWAX. El tiempo de corrido empleado fue de 18,5 minutos, usando Helio ultra puro, 99,99% de pureza como gas de arrastre y la cuantificación se llevó a cabo en el extracto líquido en términos de concentración (µg/mL. En la investigación se pudo validar la metodología, obteniendo porcentajes de recuperación que oscilaron entre el 75,0 y el 98,2 % para todos los analitos y los límites de cuantificación en µg/mL fueron 0,279; 0,337; 0,349; 0,391; 0,355 y 0,356; para Benceno, Tolueno, Etilbenceno, p-xileno; m-xileno y o-xileno, respectivamente y se logró demostrar que el método validado fue selectivo, específico, lineal, preciso y exacto.

  11. Percutaneous penetration via hand eczema is the major accelerating factor for systemic absorption of toluene and xylene during car spray painting.

    Science.gov (United States)

    Hino, Ryosuke; Nishio, Daisuke; Kabashima, Kenji; Tokura, Yoshiki

    2008-02-01

    For absorption of organic solvents, the respiratory tract is well known as the major site, but percutaneous absorption might be critical in some workplaces. The aim of the study is to determine whether the skin, if disordered, is 1 of the major routes of organic solvent absorption. 72 male workers who painted the car body in the booth of a Japanese car company were participated in this study. The severity of hand eczema, urinary metabolites of organic solvents and the concentration of airborne organic solvents were measured. The correlation coefficiency between the skin severity index and the urinary concentration of hippuric acid or methylhippuric acid was statistically significant. There was no significant correlation between their urinary values and the air concentration of mixed organic solvents. The skin is a more critical absorption route for organic solvents than the respiratory tract in some occupational settings. Hand eczema is a common disease and has a possibility to be a critical absorption route of organic solvents.

  12. Problem Definition Studies on Potential Environmental Pollutants. 4. Physical, Chemical, Toxicological, and Biological Properties of Benzene; Toluene; Xylenes; and para-Chlorophenyl Methyl Sulfide, Sulfoxide, and Sulfone

    Science.gov (United States)

    1976-06-01

    Amounts of Benzene in the Air of Industrial Facilities," r ’Koks I Khimiya, 5:36-67 (1973); C.A., 79, 34722h (1973). 48. Balint , T., S. Igelewski, E...5:36-37 (1973); C.A., 79:34722H (1973). 26. Balint , T., S. Igelewski, E. Kerenyi, J. Stumpfhauser, G. Kerenyi and T. Molnar, "Apparatus for Measuring...34Detennina- tion of Small Amounts of Benzene in the Air of Industrial Facil-ities," Koks I Khlrn, 5:36-37 (1973); C.A.. 79:34722H1 (1973). 77 23. Balint

  13. Validation of a methodology to determine Benzene, Toluene, Ethylbenzene, and Xylenes concentration present in the air and adsorbed in activated charcoal passive samplers by GC/ FID chromatography

    OpenAIRE

    Mary Luz Gallego-Díez; Mauricio Andrés Correa-Ochoa; Julio César Saldarriaga-Molina

    2016-01-01

    En este trabajo se presenta la validación del procedimiento analítico que permite determinar las concentraciones de Benceno (B), Tolueno (T), Etilbenceno (E) y Xilenos (X), compuestos conocidos como BTEX, presentes en el aire y adsorbidos sobre carbón activado, usando el método de adición de estándar interno (Fluorobenceno) para la cuantificación. En el proceso se empleó carbón activado de referencia para la validación y carbón granular (CGC) a base de coco para la construcción de los captado...

  14. An in-situ FTIR study of the side-chain alkylation of toluene with methanol

    International Nuclear Information System (INIS)

    King, S.T.; Garces, J.

    1985-01-01

    The side-chain alkylation of toluene with methanol to styrene and ethylbenzene can be an economically attractive industrial process if it has high enough conversion and selectivity. This process has been investigated by many others using zeolites or metal oxides as the catalyst. It has been generally accepted that high basicity in certain size pores in the catalyst is required for such side-chain alkylation. However, the actual reaction mechanism is still not understood. In this paper the results of an in-situ FT-IR study of the side-chain alkylation in Li, Na, K, Rb and Cs exchanged X zeolites is discussed. It was found that the KX, RbX and CsX zeolites, which are capable of side-chain alkylation, also form surface formate and a surface precursor of formate from methanol decomposition. While the surface formate itself is not the alkylation agent, the observed formate precursor may be the intermediate for side-chain alkylation

  15. Effect of ethanol, cimetidine and propranolol on toluene metabolism in man

    DEFF Research Database (Denmark)

    Døssing, M; Bælum, Jesper; Hansen, S H

    1984-01-01

    In a climatic exposure chamber four healthy volunteers were exposed to 100ppm toluene, 100ppm toluene + ethanol, 100ppm toluene + cimetidine, and 100ppm toluene + propranolol for 7h each at random over four consecutive days. A control experiment and 3.5h of exposure to 200ppm toluene were also...... of exposure the increase was by 3.3. Neither cimetidine nor propranolol changed toluene metabolism significantly. The results indicate that ethanol may prolong the time interval in which toluene is retained in the human body in persons simultaneously exposed to ethanol and toluene. When using o...

  16. Unimolecular dissociation of doubly ionized toluene and electron transfer between neutral toluene and its dication

    Czech Academy of Sciences Publication Activity Database

    Shaffer, Christopher; Schröder, Detlef; Zins, E. L.; Alcaraz, Ch.; Žabka, Ján; Roithová, J.

    2012-01-01

    Roč. 534, 1 May (2012), s. 8-12 ISSN 0009-2614 R&D Projects: GA ČR GA203/09/1223; GA ČR GAP208/11/0446 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : dications * electron transfer * photoionization * toluene * synchrotron radiation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.145, year: 2012

  17. Oxidation of styrene to benzaldehyde/benzoic acid

    Indian Academy of Sciences (India)

    spectroscopy and powder X-ray crystallography. Keywords. Heptamolybdate type polyoxometalate cluster anion; transition metal coordination complexes; oxidation of styrene; hydrogen peroxide as an oxidant; catalysis. 1. Introduction. Over the last ...

  18. Styrene-Based Copolymer for Polymer Membrane Modifications

    Directory of Open Access Journals (Sweden)

    Harsha Srivastava

    2016-05-01

    Full Text Available Poly(vinylidene fluoride (PVDF was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffraction (XRD experiments that the modified PVDF membranes show a drastic reduction in their crystallinity. The neat PVDF membrane has the highest degradation rate, which decreased with the addition of the styrene-based copolymer.

  19. Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films

    KAUST Repository

    Chafin, Raymond

    2010-07-01

    Procedures for Torlon® 4000T membrane formation were developed to provide attractive and repeatable xylene separation properties. Torlon® 4000T membrane films cast by our method were investigated in terms of thermally induced imidization, molecular weight enhancement, and solvent removal. After development of the Torlon® 4000T casting procedure, pervaporation of a xylene mixture (i.e. 30% para-xylene, 30% meta-xylene, 30% ortho-xylene, and 10% ethylbenzene) was performed in both Torlon® 4000T and post casting annealed Torlon® 4000T films. The xylene pervaporation in annealed Torlon® 4000T film at 200°C gave a permeability of 0.25 Barrer and a selectivity of 3.1 (para/ortho) and 2.1 (para/meta) respectively. A so-called " permeability collapse" reflecting an accelerated reduction in the free volume is consistent with significant temperature-induced changes in the films observed after thermal annealing at 300°C. This conditioning effect is induced by a combination of heat treatment and the presence of the interacting aromatic penetrants. Optical methods were used to verify that the density of annealed samples exposed to xylene for 5 days eventually increased, suggesting that the membrane is originally swollen upon initial xylene exposure, and then relaxes to a more densified, and more discriminating state. © 2010 Elsevier Ltd.

  20. Fixed-bed adsorption separation of xylene isomers over sio2/silicallite-1 core-shell adsorbents

    KAUST Repository

    Khan, Easir A.

    2013-12-29

    SiO2/Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin polycrystalline silicalite-1 shell which was synthesized via a self-assembly of silicalite-1 nanocrystals on core silica surface followed by a secondary seeded growth method. The core materials, SiO2 used in this study has mesoporosity with an average pore diameter of 60Å and hence offers no shape selectivity for xylene isomers. However, the shell, silicalite-1 contains rigid pore structures and preferentially adsorbs p-xylene from their isomers mixtures. A series of adsorption fixed bed breakthrough adsorption/desorption experiment was performed to obtain the equilibrium isotherms and adsorption isotherm parameters of xylene isomers. The equilibrium isotherms of xylene isomers follow the Langmuir\\'s model. A chromatographic adsorption model has been used to describe the fixed-bed breakthrough profiles of xylene isomers. The model has successfully predicted the responses of the binary mixtures of p/o-xylene isomers. The SiO2/silicalite-1 core-shell adsorbents have shown para-selectivity as high as 15. © Bangladesh Uni. of Engg. & Tech.

  1. Isotope effect in thermodynamic parameters of styrene polymerization

    International Nuclear Information System (INIS)

    Lebedev, B.V.; Lebedev, N.K.; Smirnova, N.N.

    1985-01-01

    Isotope effects in the enthalpy, entropy and Gibbs energy of the styrene polymerization process are detected by adiabatic- and isothermal calorimetry methods. Thermodynamic parameters of styrene- and deuterostyrene polymerization are calculated in the range from 0 to 350 K. Differences in thermodynamic quantities of these processes are explained by the influence of hydrogen substitution by deuterium and constitute: for enthalpy and Gibbs energy 2-3 kJ/mol, for entropy - 2-3 J/(mol x k)

  2. Obtainment of butadiene-styrene copolymers functionalized with hydroxypropyl methacrylate

    International Nuclear Information System (INIS)

    Luz, Rinaldo F. da; Furtado, Cristina R.G.; Soares, Bluma G.

    2011-01-01

    The elastomeric butadiene-styrene copolymers obtained by the emulsion polymerization process are widely used in compositions of tire tread providing good balance among properties, processability and cost. In this paper it was evaluated the presence of hydroxypropyl methacrylate (HPMA) instead styrene monomer, the concentration of 3% and 5% during the process. The characterization of the functionality was performed by FTIR and 13 C NMR and its influence the polymer microstructure was determined by the SEC, DSC and the Mooney viscosity. (author)

  3. Preliminary response of a pristine aquifer when facing toluene contamination

    Science.gov (United States)

    Qiu, S.; Herzyk, A.; Maloszewski, P.; Larentis, M.; Griebler, C.; Elsner, M.

    2012-04-01

    Toluene is a common groundwater contaminant due to the wide spread of gasoline and industrial solvents. The understanding of how and when ecosystems initially respond to the presence of toluene is yet limited, because field investigations rarely start before a contamination has occurred. In order to investigate for the first time such a scenario, a pristine indoor aquifer model (0.8 - 0.7 - 5 m) was constructed, filled with natural sediment, flushed with natural groundwater at a rate of 9 L/hr, and subsequently exposed to a toluene contamination. Investigation was done to the chemical and biological parameters of the model, including oxygen concentration (9.6 mg/L), nitrate concentration (5.8 mg/L), small organic carbon content (0.8 mg/L), microbial abundance (4 x 104 cell/mL), and ATP (0.01 nM). This agreed with the condition of a typical pristine and oligotrophic aquifer. A 30-hr aqueous toluene pulse (water saturated with toluene) was injected into the system together with a conservative tracer (90% D2O). Water samples were collected 4.2 m away from the injection source. The comparison between the toluene and D2O breakthrough curves indicated that a portion of toluene was removed by degradation at a pseudo 1st order rate of 0.017/hr. Stable carbon isotope values of toluene were also measured along with the breakthrough curves. δ13C values were more positive than the original input, confirming that biodegradation had taken place. Subsequent to the pulse, a constant injection of aqueous toluene together with bromide was applied to obtain a deeper insight of the biological and geochemical processes in the aquifer. High resolution water sampling over the entire aquifer model was conducted 80 hrs after the start of constant injection. Microbial abundance and living biomass (ATP) were observed to be 10 - and 100 -, respectively, higher than under pristine conditions. Biodegradation was detected by comparing the concentration of toluene and bromide, and was confirmed

  4. Styrene-divinylbenzene copolymers loaded with organophosphorus chelating agents for rare earths separation

    International Nuclear Information System (INIS)

    Barbosa, Celina C.R.; Teixeira, Viviane G.; Coutinho, Fernanda M.B.

    1998-01-01

    Styrene-divinylbenzene copolymers used in extraction chromatography were synthesized in presence of selective chelating agents for rare earths: DEHPA, bis (2-ethylhexyl) phosphoric acid, and EHEHPA, bis (2-ethylhexyl) phosphonic acid. The copolymers were prepared by suspension polymerization technique using the pure chelating agents and its mixture with toluene (TOL) as diluents. The influence of synthesis conditions such as chelating agent/TOL ratios, dilution degree of monomers and amount of DVB on the porous structure of the copolymers were studied. The porous structure was characterized by the apparent density, fixed pore volume, surface area and by optical and scanning electron microscopy. The performance of the copolymers in the separation process of rare earths was evaluated. The total chelating capacity of each copolymer and the chelating kinetics in relation to gadolinium ion were determined. The chelating agent content of the copolymers depend on the amount of chelating agents employed in the synthesis. The highest amount of chelating agent that can be used in the synthesis in order to produce copolymers with high chelating capacity and good mechanical properties was determined. The total chelating capacity varied with the content of the chelating agents in the copolymer and the chelating kinetics was dependent mainly on the pore diameter, because this parameter determines the diffusion rate of the ions though the copolymer structure. (author)

  5. Engineering Styrene Monooxygenase for Biocatalysis: Reductase-Epoxidase Fusion Proteins.

    Science.gov (United States)

    Heine, Thomas; Tucker, Kathryn; Okonkwo, Nonye; Assefa, Berhanegebriel; Conrad, Catleen; Scholtissek, Anika; Schlömann, Michael; Gassner, George; Tischler, Dirk

    2017-04-01

    The enantioselective epoxidation of styrene and related compounds by two-component styrene monooxygenases (SMOs) has targeted these enzymes for development as biocatalysts. In the present work, we prepare genetically engineered fusion proteins that join the C-terminus of the epoxidase (StyA) to the N-terminus of the reductase (StyB) through a linker peptide and demonstrate their utility as biocatalysts in the synthesis of Tyrain purple and other indigoid dyes. A single-vector expression system offers a simplified platform for transformation and expansion of the catalytic function of styrene monooxygenases, and the resulting fusion proteins are self-regulated and couple efficiently NADH oxidation to styrene epoxidation. We find that the reductase domain proceeds through a sequential ternary-complex mechanism at low FAD concentration and a double-displacement mechanism at higher concentrations of FAD. Single-turnover studies indicate an observed rate constant for FAD-to-FAD hydride transfer of ~8 s -1 . This step is rate limiting in the styrene epoxidation reaction and helps to ensure that flavin reduction and styrene epoxidation reactions proceed without wasteful side reactions. Comparison of the reductase activity of the fusion proteins with the naturally occurring reductase, SMOB, and N-terminally histidine-tagged reductase, NSMOB, suggests that the observed changes in catalytic mechanism are due in part to an increase in flavin-binding affinity associated with the N-terminal extension of the reductase.

  6. Sinonasal adenocarcinoma following styrene exposure in the reinforced plastics industry.

    Science.gov (United States)

    Nissen, Mette Schou; Stokholm, Zara Ann; Christensen, Mette Skovgaard; Schlünssen, Vivi; Vestergaard, Jesper Medom; Iversen, Inge Brosbøl; Kolstad, Henrik Albert

    2018-03-14

    Sinonasal adenocarcinoma is a rare disease expected to have rare causes and potential for strong risk factors as reflected by the strong association with occupational wood dust exposure. High level styrene exposure is a rare and suspected carcinogen, and this study examines the exposure-response relation between occupational styrene exposure, sinonasal adenocarcinoma and other subtypes. We followed 73 092 styrene-exposed workers from 1968 to 2011 and identified sinonasal cancers in the Danish Cancer Registry. We modelled cumulative styrene exposure and estimated incidence rates and age, sex and wood-industry adjusted ORs. During 1 585 772 person-years, we observed nine cases of adenocarcinoma, corresponding to a fivefold non-significantly increased OR for estimates of high versus low cumulative styrene exposure (OR 5.11, 95% CI 0.58 to 45.12). The increased risk was confined to exposure received during the recent 15 years. The other histological subtypes showed no increased risk. This study suggests increased risk of sinonasal adenocarcinoma following styrene exposure. The observations are, however, few, confounding from wood dust exposure cannot be ruled out, and additional studies are needed before firm conclusions can be drawn. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Ordered, microphase-separated, noncharged-charged diblock copolymers via the sequential ATRP of styrene and styrenic imidazolium monomers

    Energy Technology Data Exchange (ETDEWEB)

    Shi, ZX; Newell, BS; Bailey, TS; Gin, DL

    2014-12-15

    A series of imidazolium-based noncharged-charged diblock copolymers (1) was synthesized by the direct, sequential ATRP of styrene and styrenic imidazolium bis(trifluoromethyl)sulfonamide monomers with methyl, n-butyl, and n-decyl side-chains. Small-angle X-ray scattering studies on initial examples of 1 with a total of 50 repeat units and styrene:imidazolium-styrene repeat unit ratios of 25:25, 20:30, and 15:35 showed that their ability to form ordered nanostructures (i.e., sphere and cylinder phases) in their neat states depends on both the block ratio and the length of the alkyl side-chain on the imidazolium monomer. To our knowledge, the synthesis of imidazolium-based BCPs that form ordered, phase-separated nanostructures via direct ATRP of immiscible co-monomers is unprecedented. (C) 2014 Elsevier Ltd. All rights reserved.

  8. Comparing the efficacy of coconut oil and xylene as a clearing agent in the histopathology laboratory.

    Science.gov (United States)

    Sermadi, Wajid; Prabhu, Sudeendra; Acharya, Swetha; Javali, Sb

    2014-09-01

    The commonly used clearing agent, xylene is supposed to be highly toxic and carcinogenic. As previous research studies have shown the effectiveness of different vegetable oils as clearants, this study was designed to evaluate the efficacy of coconut oil. Two equal halves of 60 soft tissue specimens were processed simultaneously in xylene and coconut oil as clearing agents. The Xylene-treated specimens (XY-S) and Coconut oil-treated specimens (CO-S) were checked for gross and histological features and comparison was done between the two groups. Significant shrinkage was noted in XY-S compared to that in CO-S. No difference was found in either of the sections when checked for cellular details and staining quality. Morphometrically, there was significant reduction in the mean cell area in XY-S compared to that in CO-S. Coconut oil may be substituted for the highly hazardous xylene as a clearing agent without compromising the quality of histological details.

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

    Czech Academy of Sciences Publication Activity Database

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

    2015-01-01

    Roč. 243, APR 2015 (2015), s. 118-127 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : transalkylation * mordenite * xylenes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  10. Kerosene: Contributing agent to xylene as a clearing agent in tissue processing.

    Science.gov (United States)

    Shah, Amisha Ashokkumar; Kulkarni, Dinraj; Ingale, Yashwant; Koshy, Ajit V; Bhagalia, Sanjay; Bomble, Nikhil

    2017-01-01

    Research methodology in oral and maxillofacial pathology has illimitable potential. The tissue processing involves many steps of which one of the most important step is "Clearing," which is a process of replacing dehydrant with a substance which is miscible with embedding medium or paraffin wax. Xylene is one of the common clearing agents used in laboratory, but it is also hazardous. The main aim of this study is to substitute conventionally used xylene by a mixture of kerosene and xylene in clearing steps without altering the morphology and staining characteristics of tissue sections. This will also minimize the toxic effects and tend to be more economical. One hundred and twenty bits of tissue samples were collected, each randomly separated into 4 groups (A, B, C and D) and kept for routine tissue processing till the step of clearing; during the step of clearing instead of conventional xylene, we used mixture of xylene and kerosene in 4 ratios ([A-K:X - 50:50]; [B-K:X - 70:30]; [C - Ab. Kerosene]; [D - Ab. Xylene - as control]) and observed for the light microscopic study adopting H and E staining, IHC (D2-40), Special stains (periodic acid-Schiff and congo red) procedure. The result was subjected to statistical analysis by using Fisher's exact test. The results obtained from the present study were compared with control group, i.e., D and it was observed that Groups A and B were absolutely cleared without altering the morphology of tissue and cellular details; optimum embedding characteristics and better staining characteristics were also noted, whereas Group C presents poor staining characteristics with reduced cellular details. Embedded tissues in Group C presented with rough, irregular surface and also appeared shrunken. Combined mixture of xylene and kerosene as a clearing agent in different ratio, i.e., Group A (K:X - 50:50) and B (K:X - 70:30) can be used without posing any health risk or compromising the cellular integrity.

  11. Pengaruh Konsentrasi Inisiator Dan Komposisi Styrene Dan Maleic Anhydride Terhadap Berat Molekul Pada Sintesis Kopolimer Poly (Styrene-Maleic Anhydride)

    OpenAIRE

    Afrinaldi, Bambang; Jayatin, Jayatin

    2014-01-01

    Pada pencampuran antara dua jenis polimer dibutuhkan kompatibilitas yang cukup baik supaya diperoleh hasil yang bagus. Fungsi polimer adalah salah satu cara untuk meningkatkan kompatibilitas dengan memberikan gugus fungsi pada suatu polimer. Studi ini mempelajari pengaruh inisiator dan komposisi monomer styrene dan maleic anhydride terhadap berat molekul pada sintesis Poly (Styrene-Maleic Anhydride) (PSMA). Polimerisasi dilakukan pada temperatur 90°C dengan inisiator benzoil peroksida (BPO). ...

  12. Acute behavioural comparisons of toluene and ethanol in human subjects.

    OpenAIRE

    Echeverria, D; Fine, L; Langolf, G; Schork, T; Sampaio, C

    1991-01-01

    A comparison of toluene and ethanol (EtOH) induced changes in central nervous system (CNS) function and symptoms were evaluated in two studies, and when possible the effects of toluene were expressed in EtOH equivalent units. The toluene concentrations were 0, 75, and 150 ppm, bracketing the American Conference of Governmental Industrial Hygienists threshold limit value (ACGIH TLV) of 100 ppm. The socially relevant EtOH doses were 0.00, 0.33, and 0.66 g EtOH/kg body weight, equivalent to two ...

  13. Effects of p-xylene inhalation on axonal transport in the rat retinal ganglion cells

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, S.S.; Lyerly, D.P. (Environmental Protection Agency, Research Triangle Park, NC (USA))

    1989-12-01

    Although the solvent xylene is suspected of producing nervous system dysfunction in animals and humans, little is known regarding the neurochemical consequences of xylene inhalation. The intent of this study was to determine the effect of intermittent, acute, and subchronic p-xylene exposure on the axonal transport of proteins and glycoproteins within the rat retinofugal tract. A number of different exposure regimens were tested ranging from 50 ppm for a single 6-hr exposure to 1600 ppm 6 hr/day, 5 days/week, for a total of 8 exposure days. Immediately following removal from the inhalation chambers rats were injected intraocularly with (35S)methionine and (3H)fucose (to label retinal proteins and glycoproteins, respectively) and the axonal transport of labeled macromolecules to axons (optic nerve and optic tract) and nerve endings (lateral geniculate body and superior colliculus) was examined 20 hr after precursor injection. Only relatively severe exposure regimens (i.e., 800 or 1600 ppm 6 hr/day, 5 days/week, for 1.5 weeks) produced significant reductions in axonal transport; there was a moderate reduction in the axonal transport of 35S-labeled proteins in the 800-ppm-treated group which was more widespread in the 1600 ppm-treated group. Transport of 3H-labeled glycoproteins was less affected. Assessment of retinal metabolism immediately after isotope injection indicated that the rate of precursor uptake was not reduced in either treatment group. Furthermore, rapid transport was still substantially reduced in animals exposed to 1600 ppm p-xylene and allowed a 13-day withdrawal period. These data indicate that p-xylene inhalation decreases rapid axonal transport supplied to the projections of the rat retinal ganglion cells immediately after cessation of inhalation exposure and that this decreased transport is still apparent 13 days after the last exposure.

  14. Effects of p-xylene inhalation on axonal transport in the rat retinal ganglion cells

    International Nuclear Information System (INIS)

    Padilla, S.S.; Lyerly, D.P.

    1989-01-01

    Although the solvent xylene is suspected of producing nervous system dysfunction in animals and humans, little is known regarding the neurochemical consequences of xylene inhalation. The intent of this study was to determine the effect of intermittent, acute, and subchronic p-xylene exposure on the axonal transport of proteins and glycoproteins within the rat retinofugal tract. A number of different exposure regimens were tested ranging from 50 ppm for a single 6-hr exposure to 1600 ppm 6 hr/day, 5 days/week, for a total of 8 exposure days. Immediately following removal from the inhalation chambers rats were injected intraocularly with [35S]methionine and [3H]fucose (to label retinal proteins and glycoproteins, respectively) and the axonal transport of labeled macromolecules to axons (optic nerve and optic tract) and nerve endings (lateral geniculate body and superior colliculus) was examined 20 hr after precursor injection. Only relatively severe exposure regimens (i.e., 800 or 1600 ppm 6 hr/day, 5 days/week, for 1.5 weeks) produced significant reductions in axonal transport; there was a moderate reduction in the axonal transport of 35S-labeled proteins in the 800-ppm-treated group which was more widespread in the 1600 ppm-treated group. Transport of 3H-labeled glycoproteins was less affected. Assessment of retinal metabolism immediately after isotope injection indicated that the rate of precursor uptake was not reduced in either treatment group. Furthermore, rapid transport was still substantially reduced in animals exposed to 1600 ppm p-xylene and allowed a 13-day withdrawal period. These data indicate that p-xylene inhalation decreases rapid axonal transport supplied to the projections of the rat retinal ganglion cells immediately after cessation of inhalation exposure and that this decreased transport is still apparent 13 days after the last exposure

  15. Interaktioner mellem organiske opløsningsmidler

    DEFF Research Database (Denmark)

    Noraberg, J J

    1993-01-01

    investigated combinations. The interactions of the solvents styrene, n-hexane, xylene, dichloromethane and toluene are described. The conclusion drawn is that the rule of additivity should be used with caution when dealing with combined exposure for organic solvents in industry. Certain solvents should...

  16. MODELING STYRENE HYDROGENATION KINETICS USING PALLADIUM CATALYSTS

    Directory of Open Access Journals (Sweden)

    G. T. Justino

    Full Text Available Abstract The high octane number of pyrolysis gasoline (PYGAS explains its insertion in the gasoline pool. However, its use is troublesome due to the presence of gum-forming chemicals which, in turn, can be removed via hydrogenation. The use of Langmuir-Hinshelwood kinetic models was evaluated for hydrogenation of styrene, a typical gum monomer, using Pd/9%Nb2O5-Al2O3 as catalyst. Kinetic models accounting for hydrogen dissociative and non-dissociative adsorption were considered. The availability of one or two kinds of catalytic sites was analyzed. Experiments were carried out in a semi-batch reactor at constant temperature and pressure in the absence of transport limitations. The conditions used in each experiment varied between 16 - 56 bar and 60 - 100 ºC for pressure and temperature, respectively. The kinetic models were evaluated using MATLAB and EMSO software. Models using adsorption of hydrogen and organic molecules on the same type of site fitted the data best.

  17. Ultrafast crosslinking of styrene-butadiene rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Decker, C.; Trieu, N.T.V. [CNRS, Mulhouse (France). Dept. de Photochimie

    2000-07-01

    Thermoplastic elastomers, like styrene-butadiene rubbers (SBS), are usually made of triblock copolymers which form segregated glassy and elastomeric domains. These polymeric materials exhibit a high elasticity and resiliency, but a poor resistance to organic solvents. Moreover, they start to flow upon heating above 80 C, the polystyrene glass transition temperature, when the physical network loses its cohesion. An effective way to make these polymers more resistant to solvents and elevated temperatures, as required for hot-melt adhesive applications, is to create covalent bonds between the elastomeric chains. Such a chemical network can be readily formed by photoinitiated crosslinking through the vinyl and butene double bonds located on the polybutadiene chain. Upon UV-curing, the shear adhesion failure temperature (SAFT) was found to rise from 80 C to over 160 C, while the polymer remained tacky and became completely insoluble. The main advantage of photoinitiation is that crosslinking is achieved within seconds at ambient temperature, selectively in the illuminated areas, by a solvent-free process. This technology is therefore of great interest for adhesives and sealants applications, as well as for the manufacture of flexographic printing plates. We report here how the curing performance of photosensitive SBS-based resins can be substantially improved by using a trifunctional thiol as crosslinking agent. (orig.)

  18. Interactions between Asphaltenes and Water in Solutions in Toluene

    DEFF Research Database (Denmark)

    Khvostichenko, Daria; Andersen, Simon Ivar

    2008-01-01

    Binding of water by asphaltenes dissolved in toluene was investigated for two asphaltene samples, OMV1 and OMV2, from the same reservoir deposit. Solubility of water in asphaltene solutions in toluene was found to increase with an increasing asphaltene concentration, indicative of solubilization...... of water by asphaltenes. Fourier transform infrared (FTIR) spectroscopy of stretching modes of OH groups in the region of 3800-3100 cm(-1) was used to obtain insight into the state of water in water-unsaturated asphaltene solutions in toluene. The number of water molecules bound to one asphaltene molecule...... was determined for water-saturated solutions (OMV1 and OMV2) and for water-unsaturated solutions (OMV1 only). These numbers were found to decrease from several water molecules per asphaltene molecule to below unity upon an increase of the asphaltene concentration in toluene from 0.1 to 20 g/L, suggesting...

  19. Microstructure Development and Its Influence on the Properties of Styrene-Ethylene-Butylene-Styrene/Polystyrene Blends

    Directory of Open Access Journals (Sweden)

    Ritima Banerjee

    2018-04-01

    Full Text Available The present work is a novel attempt to understand the microstructure of styrene-ethylene-butylene-styrene (SEBS/polystyrene (PS blends not only through morphological studies, but also thermal, mechanical and rheological characterizations. SEBS/PS blends containing 10, 30 and 50 wt % PS were processed in a micro-compounder and characterized. Scanning electron microscopy (SEM studies, with selective staining of the PS phase, revealed the presence of PS as nanometer-sized domains, as well as phase-separated micrometer-sized aggregates. Blends with 30 and 50 wt % PS exhibited a fibrillar microstructure, obeying Hirsch’s model of short fiber composites. A remarkable increase in glass transition temperature indicated a strong interaction of the fibrils with SEBS. All blends showed two modes of relaxation corresponding to the two phases. A single mode of relaxation of the PS phase has been attributed to combined effects of the partial miscibility of the added PS, along with the interaction of the fibrils with SEBS. The long relaxation time of the elastomeric phase indicated the tendency of these materials to undergo time-dependent shrinkage in secondary processing operations. An increase in PS content resulted in the lowering of the shear viscosity and energy requirement for mixing, indicating the ease of processing.

  20. Spectrophotometric study of the interaction of methylene blue with poly(styrene-co-sodium styrene sulfonate

    Directory of Open Access Journals (Sweden)

    Souha Ben Mahmoud

    2016-05-01

    Full Text Available The interaction of the cationic phenothiazine dye, the Methylene Blue (MB with poly-(sodium styrene sulfonatef–co-(styrene1-f, (PSSNa f, has been investigated by spectrophotometric method. The polyelectrolyte induced metachromasy resulting in a blue shift of the absorption maxima of the dye, in agreement with the formation of dye H-aggregates. The stability of the PSSNa-MB complexes was studied as a function of polyelectrolyte chain length, polyelectrolyte electrostatic charge density f, polyelectrolyte concentration, NaCl salt addition, tetrahydrofurane (THF addition and THF treatment. The stoichiometry of PSSNa-MB complex evaluated by the molar ratio method was found 4:1 for the fully charged PSSNa f = 1. Reversal of metachromasy was observed upon salt and THF addition, while THF treatment does not affect the complex and allows recovering the initial complex. Finally, thermodynamic parameters of the interaction between the polyelectrolyte and the dye at different temperatures, namely free energy DG, the enthalpy DH and the entropy DS have been evaluated to determine the binding constant and as a consequence the stability of the complex. The metachromasy effect was found to be more high as the chemical charge f increases and reaches its maximum value f = 1, when operating at optimal conditions. So, the PSSNa f = 1-MB complex is the most stable in comparison to the others based on lower charge density PSSNa f.

  1. EFFECTS OF STYRENE-BUTADIENE-STYRENE ON STIFFNESS OF ASPHALT CONCRETE AT DIFFERENT TRAFFIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    GHOLAMALI SHAFABAKHSH

    2016-04-01

    Full Text Available The previous studies have explored the effects of Styrene-Butadiene-Styrene (SBS as the most prevalent modifier for asphalt mixtures. The current study intends to compare stiffness modulus of control and SBS modified asphalt mixtures under different traffic loadings. To this end, resilient modulus tests were performed on both conventional and SBS modified specimens. Tests were conducted at 5, 25 and 40°C with loading times of 50, 100, 300, 600 and 1000 milliseconds and 4, 9 and 30 as ratio of rest periods (between loading pulses to loading times (R/L. Using these test parameters and haversine and square loading pulses that represent vertical stress distribution at different depths within an asphalt layer, a variety of traffic densities and vehicle speeds were simulated and their effects on stiffness of asphalt concrete were determined. Results indicated that SBS modification provide higher stiffness under haversine pulse with long loading time at 40°C, so that it was about 3 times of unmodified mixture stiffness. The effect of traffic density that represented by R/L was significant only in long loading time (1000 ms especially under haversine pulse.

  2. Dynamics and the Regiochemistry of Nitration of Toluene

    OpenAIRE

    Nieves-Quinones, Yexenia; Singleton, Daniel A.

    2016-01-01

    The regiochemistry of the nitration of toluene by NO2+BF4− in dichloromethane is accurately predicted from trajectories in explicit solvent. Simpler models and approaches based on transition state theory fail to account for the selectivity. Potential of mean force calculations find no free-energy barrier for reaction of the toluene/NO2+BF4− encounter complex, yet the trajectories require an extraordinary 3 ps to descend an exergonic slope. The selectivity is decided late in long trajectories ...

  3. Atrioventricular conduction abnormality and hyperchloremic metabolic acidosis in toluene sniffing

    Directory of Open Access Journals (Sweden)

    Jian-Hsiung Tsao

    2011-10-01

    Full Text Available Toluene is an aromatic hydrocarbon with widespread industrial use as an organic solvent. As a result of the euphoric effect and availability of these substances, inhalation of toluene-based products is popular among young adults and children. Chronic or acute exposure is known to cause acid–base and electrolyte disorders, and to be toxic to the nervous and hematopoietic systems. We report a 38-year-old man who suffered from general muscular weakness of all extremities after toluene sniffing, which was complicated with hypokalemic paralysis, atrioventricular conduction abnormality, and normal anion gap hyperchloremic metabolic acidosis. Renal function, serum potassium and acid–base status normalized within 3 days after aggressive potassium chloride and intravenous fluid replacement. Electrocardiography showed regression of first-degree atrioventricular block. Exposure to toluene can lead to cardiac arrhythmias and sudden sniffing death syndrome. Tachyarrhythmia is the classical manifestation of toluene cardiotoxicity. Atrioventricular conduction abnormalities have been rarely mentioned in the literature. Knowledge of the toxicology and medical complications associated with toluene sniffing is essential for clinical management of these patients.

  4. Toluene diffusion and reaction in unsaturated Pseudomonas putida biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Holden, P.A.; Hunt, J.R.; Firestone, M.K. [Univ. of California, Berkeley, CA (United States)

    1997-12-20

    Biofilms are frequently studied in the context of submerged or aquatic systems. However, much less is known about biofilms in unsaturated systems, despite their importance to such processes as food spoilage, terrestrial nutrient cycling, and biodegradation of environmental pollutants in soils. Using modeling and experimentation, the authors have described the biodegradation of toluene in unsaturated media by bacterial biofilms as a function of matric water potential, a dominant variable in unsaturated systems. They experimentally determined diffusion and kinetic parameters for Pseudomonas putida biofilms, then predicted biodegradation rates over a range of matric water potentials. For validation, the authors measured the rate of toluene depletion by intact biofilms and found the results to reasonably follow the model predictions. The diffusion coefficient for toluene through unsaturated P. putida biofilm averaged 1.3 {times} 10{sup {minus}7} cm{sup 2}/s, which is approximately two orders of magnitude lower than toluene diffusivity in water. Their studies show that, at the scale of the microbial biofilm, the diffusion of toluene to biodegrading bacteria can limit the overall rate of biological toluene depletion in unsaturated systems.

  5. Single Pot Benzylation of O-Xylene with Benzyl Chloride and Benzyl Alcohol Over Pillared Montmorillonites

    Directory of Open Access Journals (Sweden)

    Kurian Manju

    2014-09-01

    Full Text Available Improvement of product selectivity is a major concern of the day. Presence of a coreactant can alter the rate as well as product selectivity of many key reactions like Friedel-Crafts benzylation. Single pot benzylation of o-xylene with benzyl chloride and benzyl alcohol was studied over transition metal exchanged pillared clay catalysts. Complete conversion of benzyl alcohol occured within one hour with 100% monoalkylated product selectivity. The reaction of o-xylene with benzyl alcohol was found to proceed fast in presence of benzyl chloride in single pot, than when present alone as the benzylating species. This enhancement occurs at the expense of no reaction of benzyl chloride, which when present alone reacts faster than benzyl alcohol. Existence of a second transition metal exchanged between the pillars increased the rate of the reaction. A detailed investigation of the reaction variables suggested preferential adsorption of benzyl alcohol to catalyst active sites as the reason.

  6. A study of the electrochemical hydrogenation of o-xylene in a PEM hydrogenation reactor

    International Nuclear Information System (INIS)

    Fonocho, R.; Gardner, C.L.; Ternan, M.

    2012-01-01

    In this study, we investigate the electrochemical hydrogenation of o-xylene in a proton exchange membrane hydrogenation reactor (PEMHR). The reactor was operated isothermally over the temperature range 20–68 °C and at a pressure of 1 atm in a semi-batch mode. Hydrogen was fed into the anode compartment and o-xylene into the cathode. The hydrogenation efficiency was investigated at different current densities and temperatures. Results obtained show that the hydrogenation efficiency increases with temperature but decreases with current density. At low current densities the hydrogenation efficiency approaches 100%. A zero dimensional model was used to fit the data and extract a rate constant for the hydrogenation reaction. The activation energy for this reaction was found to be 28 kJ/mole.

  7. Influence of substituents on positron annihilation in styrene copolymers

    International Nuclear Information System (INIS)

    Baranowski, A.; Debowska, M.; Jerie, K.; Rudzinska-Girulska, J.

    1995-01-01

    Results of angular correlation of annihilation radiation (ACAR) and positron annihilation lifetime (PAL) measurements are presented for five styrene copolymers: poly(co-styrene-phenylmaleimide) and its three derivatives with chlorine as well as for one with the OH group substituted at the benzene ring. It occurs that the chlorine substituted at three different positions at the benzene ring poly(co-styrene-o (or -m,-p)-chlorophenylmaleimide) inhibits the formation of the positronium to different extent. The greatest effect is observed in case of the chlorine atom substituted at the benzene ring at the ortho-position towards the nitrogen atom. The two long lifetime (τ 3 and τ 4 ) observed in the lifetime spectra are connected with the bimodal distributions of the free volume radius in the samples. (author) 13 refs.; 3 figs.; 3 tabs

  8. Radiation grafting of styrene on starch with high efficiency

    Science.gov (United States)

    Sheikh, N.; Akhavan, A.; Ataeivarjovi, E.

    2013-04-01

    Wheat starch grafted with polystyrene (PS-g-starch) was synthesized via polymerization grafting of styrene on starch by gamma-ray. The effects of starch/styrene weight ratio, and amount of applied doses (5-40 kGy) on the percentage of grafting, G (%), were investigated. The results showed that G (%) increased with increasing starch content. The optimum condition, starch/styrene weight ratio 1/3 and the applied dose 10 kGy, led to 252.9% of grafting. The obtained graft copolymer was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, and scanning electron microscopy. FTIR spectroscopy as well as the XRD analysis exhibited the changes in chemical and crystalline structure of starch after grafting reaction. TGA demonstrated the changes in thermal stability of PS-g-starch copolymer. SEM micrographs indicated porous patches of PS adhering on the starch.

  9. Cyclic Biphalin Analogues Incorporating a Xylene Bridge: Synthesis, Characterization, and Biological Profile.

    Science.gov (United States)

    Stefanucci, Azzurra; Carotenuto, Alfonso; Macedonio, Giorgia; Novellino, Ettore; Pieretti, Stefano; Marzoli, Francesca; Szűcs, Edina; Erdei, Anna I; Zádor, Ferenc; Benyhe, Sándor; Mollica, Adriano

    2017-08-10

    In this work we enhanced the ring lipophilicity of biphalin introducing a xylene moiety, thus obtaining three cyclic regioisomers. Novel compounds have similar in vitro activity as the parent compound, but one of these ( 6a ) shows a remarkable increase of in vivo antinociceptive effect. Nociception tests have disclosed its significant high potency and the more prolonged effect in eliciting analgesia, higher than that of biphalin and of the disulfide-bridge-containing analogue ( 7 ).

  10. Substoichiometric extraction of rubidium with Dibenzo-24-crown-8 into Xylene

    International Nuclear Information System (INIS)

    Bag, M.; Chattopadhyay, P.; Basu, S.

    2014-01-01

    Owing to immense applications of rubidium in varied fields, extraction and quantification of rubidium have gained great importance in recent years. Here, studies on substoichiometric extraction of rubidium by dibenzo-24-crown-8 into xylene using 86 Rb radiotracer are reported. The method has been optimized by pH of the medium, effects of diverse ions, etc, to explore its applicability in real samples

  11. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate and...

  12. POTENTIAL FOR REDUCING STYRENE EXPOSURES FROM COPIED PAPER THROUGH USE OF LOW-EMITTING TONERS

    Science.gov (United States)

    The paper reports results of tests, conducted using 53-L chambers to determine styrene emission rates from freshly copied paper produced on a single photocopier using two toners manufactured for the copier having different styrene contents. Copied-paper styrene emissions with bot...

  13. Controlled Functionalization of Olefin/styrene Copolymers through Free Radical Processes

    NARCIS (Netherlands)

    Passaglia, Elisa; Aglietto, Mauro; Ciardelli, Francesco; Picchioni, Francesco

    2000-01-01

    The functionalization of styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS) and styrene-co-butadiene (SBR) random copolymer by free radical processes is presented. SEBS was functionalized in the melt with diethyl maleate (DEM) and dicumyl peroxide (DCP) as initiator. The

  14. Dermal absorption and disposition of musk ambrette, musk ketone and musk xylene in human subjects.

    Science.gov (United States)

    Hawkins, David R; Elsom, Lionel F; Kirkpatrick, David; Ford, Richard A; Api, Anne Marie

    2002-05-28

    Musk ambrette, musk ketone and musk xylene have a long history of use as fragrance ingredients, although musk ambrette is no longer used in fragrances. As part of the review of the safety of these uses, it is important to consider the systemic exposure that results from these uses. Since the primary route of exposure to fragrances is on the skin, dermal doses of carbon-14 labelled musk ambrette, musk ketone and musk xylene were applied to the backs (100 cm2) of healthy human volunteers (two to three subjects) at a nominal dose level of 10-20 microg/cm2 and excess material removed at 6 h. Means of 2.0% musk ambrette, 0.5% musk ketone and 0.3% musk xylene were absorbed based on the amounts excreted in urine and faeces during 5 days. Most of the material was excreted in the urine with less than 10% of the amount excreted being found in faeces. No radioactivity was detected in any plasma sample, consistent with low absorption, and no radioactivity was detected (<0.02% dose) in skin strips taken at 120 h. Analysis of urine samples indicated that all three compounds were excreted mainly as single glucuronide conjugates. The aglycones were chromatographically different, but of similar polarity, to the major rat metabolites excreted in bile also as glucuronides.

  15. Friedel-Crafts Alkylation of o-xylene over V2O5/ZrO2 Catalysts

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-01-01

    Full Text Available and considerably more selective than the conventional homogeneous Lewis acid catalysts. The investigation of vanadia systems-catalyzed benzylation of o-xylene with benzyl chloride revealed that the catalytic activity and product selectivity are sensitive...

  16. Radiation chemistry of polystyrene and styrene-butadiene copolymer

    International Nuclear Information System (INIS)

    Chau, T.C.

    1973-01-01

    Aqueous polystyrene emulsions were gamma irradiated at 30degC and at 0.6 Mrad/hour dose rate. Chain scission was negligible. Attempts to predict a dose-gel relationship were unsuccessful. Cross-linking is postulated to ossur through a hot reaction involving adjacent active species. Radiation behavior of gel free butadiene-styrene copolymers at 30degC was independent of dose rate in the range 0.04-0.46 Mrad/hour. Intramolecular crosslinking was evident only with high styrene content copolymer. (ECB)

  17. Influence of organobentonite structure on toluene adsorption from water solution

    Directory of Open Access Journals (Sweden)

    Nuria Vidal

    2012-12-01

    Full Text Available Due to increase water pollution by organic compound derived from hydrocarbons such as toluene, several alternative technologies for remediation of polluted water have been originated. In this work natural bentonites were modified with cetyltrimethylammonium (CTMA+ for obtaining organophilic bentonites. The obtained CTMA-bentonites would be suitable for use as adsorbents of toluene present in water. The influence of structural characteristics of CTMA-bentonites on their adsorption capacity was studied. It was shown that adsorption of toluene depended on homogeneous interlayer space associated with arrangements of CTMA+ paraffin-monolayer and bilayer models, accompanied by a high degree ordering of the carbon chain of organic cation in both arrangements. However, packing density would not have an evident influence on the retention capacity of these materials. The solids obtained were characterized by chemical analysis, X-ray diffractions and infrared spectroscopy. Toluene adsorption was measured by UV-visible spectrophotometer. Adsorption capacity was studied by determining adsorption isotherms and adsorption coefficient calculation. The adsorption isotherms were straight-line indicating a partition phenomenon of toluene between the aqueous and organic phase present in organophilic bentonites.

  18. Audition and exhibition to toluene - a contribution for the theme

    Directory of Open Access Journals (Sweden)

    Kulay, Luiz Alexandre

    2012-01-01

    Full Text Available Introduction: With the technological advances and the changes in the productive processes, the workers are displayed the different physical and chemical agents in its labor environment. The toluene is solvent an organic gift in glues, inks, oils, amongst others. Objective: To compare solvent the literary findings that evidence that diligent displayed simultaneously the noise and they have greater probability to develop an auditory loss of peripheral origin. Method: Revision of literature regarding the occupational auditory loss in displayed workers the noise and toluene. Results: The isolated exposition to the toluene also can unchain an alteration of the auditory thresholds. These audiometric findings, for ototoxicity the exposition to the toluene, present similar audiograms to the one for exposition to the noise, what it becomes difficult to differentiate a audiometric result of agreed exposition - noise and toluene - and exposition only to the noise. Conclusion: The majority of the studies was projected to generate hypotheses and would have to be considered as preliminary steps of an additional research. Until today the agents in the environment of work and its effect they have been studied in isolated way and the limits of tolerance of these, do not consider the agreed expositions. Considering that the workers are displayed the multiples agent and that the auditory loss is irreversible, the implemented tests must be more complete and all the workers must be part of the program of auditory prevention exactly displayed the low doses of the recommended limit of exposition.

  19. Copolymerization of propene and styrene using a zirconocene - methylaluminoxane initiator system

    International Nuclear Information System (INIS)

    Rabagliati, F.M.; Rodriguez, F.J.; Quijada, R.; Galland, G.B.

    2009-01-01

    The copolymerization of propene with styrene has been tested using the rac-Et(Ind) 2 ZrCl 2 -methylaluminoxane initiator system. The various proportion of styrene in initial feed showed an important effect on the polymerization activity. Low contents of styrene in the reaction produced a considerable fall in the activity. Respect to thermal behavior, it is noted that obtained propene/styrene copolymers showed Tm values slightly lower than the corresponding polypropene one. NMR spectroscopy allowed to confirm that the copolymer composition includes a very low incorporation of styrene in polypropylene chains. (author)

  20. New aspects in the biomonitoring of occupational exposure to styrene

    Czech Academy of Sciences Publication Activity Database

    Vodička, Pavel; Štětina, R.; Koskinen, M.; Souček, P.; Vodičková, L.; Hlaváč, P.; Kuricová, M.; Nečasová, R.; Hemminki, K.

    2002-01-01

    Roč. 75, - (2002), s. S75-S85 ISSN 0340-0131 R&D Projects: GA ČR GA313/99/1460; GA ČR GA310/01/0802 Institutional research plan: CEZ:AV0Z5039906 Keywords : styrene * biological monitoring * DNA adducts Subject RIV: FM - Hygiene Impact factor: 1.352, year: 2002

  1. Synthesis of crosslinked poly(styrene-co-divinylbenzene-co ...

    Indian Academy of Sciences (India)

    Administrator

    Colloidal particle; emulsion polymerization; polystyrene; critical micelle concentration (CMC); surface charge density; charges per ... be varied very sharply by varying the surfactant concentration below the critical micellar con- ... water was added and the temperature was increased to. 50°C. Freshly deoxygenated styrene ...

  2. Microstructure and properties of styrene acrylate polymer cement concrete

    NARCIS (Netherlands)

    Undetermined, U.

    1995-01-01

    The paper systematically describes the evolution of the microstructure of a styrene acrylate polymer cement concrete in relation to its mechanical properties and durability. The results presented and discussed at the present paper involve the interaction of the polymer dispersion with portland

  3. Highly selective cobalt-catalyzed hydrovinylation of styrene

    NARCIS (Netherlands)

    Grutters, M.M.P.; van der Vlugt, J.I.; Pei, Y.; Mills, A.M.; Lutz, M.; Spek, A.L.; Müller, Christian; Moberg, C.; Vogt, D.

    2009-01-01

    Phosphine complexes of cobalt halide salts activated by diethylaluminum chloride are shown to yield highly active catalysts in the hydrovinylation of styrene, with unprecedented high selectivity to the desired product 3-phenyl-1-butene (3P1B). Double-bond isomerization, a common problem in

  4. Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups.

    Science.gov (United States)

    Husár, Branislav; Moszner, Norbert; Lukáč, Ivan

    2012-01-01

    (±)-10-Methacryloyloxycamphorquinone (MCQ) was synthesized from (±)-10-camphorsulfonic acid either by a known seven-step synthetic route or by a novel, shorter five-step synthetic route. MCQ was copolymerized with styrene (S) and the photochemical behavior of the copolymer MCQ/S was compared with that of a formerly studied copolymer of styrene with monomers containing the benzil (BZ) moiety (another 1,2-dicarbonyl). Irradiation (λ > 380 nm) of aerated films of styrene copolymers with monomers containing the BZ moiety leads to the insertion of two oxygen atoms between the carbonyl groups of BZ and to the formation of benzoyl peroxide (BP) as pendant groups on the polymer backbone. An equivalent irradiation of MCQ/S led mainly to the insertion of only one oxygen atom between the carbonyl groups of camphorquinone (CQ) and to the formation of camphoric anhydride (11) covalently bound to the polymer backbone. While the decomposition of pendant BP groups formed in irradiated films of styrene copolymers with pendant BZ groups leads to crosslinking, only small molecular-weight changes in irradiated MCQ/S were observed.

  5. Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups

    Directory of Open Access Journals (Sweden)

    Branislav Husár

    2012-03-01

    Full Text Available (±-10-Methacryloyloxycamphorquinone (MCQ was synthesized from (±-10-camphorsulfonic acid either by a known seven-step synthetic route or by a novel, shorter five-step synthetic route. MCQ was copolymerized with styrene (S and the photochemical behavior of the copolymer MCQ/S was compared with that of a formerly studied copolymer of styrene with monomers containing the benzil (BZ moiety (another 1,2-dicarbonyl. Irradiation (λ > 380 nm of aerated films of styrene copolymers with monomers containing the BZ moiety leads to the insertion of two oxygen atoms between the carbonyl groups of BZ and to the formation of benzoyl peroxide (BP as pendant groups on the polymer backbone. An equivalent irradiation of MCQ/S led mainly to the insertion of only one oxygen atom between the carbonyl groups of camphorquinone (CQ and to the formation of camphoric anhydride (11 covalently bound to the polymer backbone. While the decomposition of pendant BP groups formed in irradiated films of styrene copolymers with pendant BZ groups leads to crosslinking, only small molecular-weight changes in irradiated MCQ/S were observed.

  6. Simultaneous production of biobased styrene and acrylates using ethenolysis

    NARCIS (Netherlands)

    Spekreijse, J.; Notre, le J.E.L.; Haveren, van J.; Scott, E.L.; Sanders, J.P.M.

    2012-01-01

    Phenylalanine (1), which could be potentially obtained from biofuel waste streams, is a precursor of cinnamic acid (2) that can be converted into two bulk chemicals, styrene (3) and acrylic acid (4), via an atom efficient pathway. With 5 mol% of Hoveyda–Grubbs 2nd generation catalyst, 1 bar of

  7. Synthesis of crosslinked poly (styrene-co-divinylbenzene-co ...

    Indian Academy of Sciences (India)

    Synthesis of crosslinked poly(styrene--divinylbenzene--sulfopropyl methacrylate) nanoparticles by emulsion polymerization: Tuning the particle size and surface charge density. Dhamodaran Arunbabu Mousumi Hazarika Somsankar Naik Tushar Jana. Polymers Volume 32 Issue 6 December 2009 pp 633-641 ...

  8. Graft copolymerization and characterization of styrene with chitosan ...

    African Journals Online (AJOL)

    In this study, styrene was successfully grafted onto chitosan by conventional free radical polymerization technique, using potassium persulphate (KPS) as the initiator. The effect of various reaction conditions including chitosan:monomer weight ratio, polymerization temperature, reaction time and concentration of initiator ...

  9. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Science.gov (United States)

    2010-04-01

    ... Drug Administration, 5100 Paint Branch Pkwy., College Park, MD 20740, or available for inspection at... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Styrene-maleic anhydride copolymers. 177.1820 Section 177.1820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  10. Occupational Styrene Exposure on Auditory Function Among Adults: A Systematic Review of Selected Workers

    Directory of Open Access Journals (Sweden)

    Francis T. Pleban

    2017-12-01

    Full Text Available A review study was conducted to examine the adverse effects of styrene, styrene mixtures, or styrene and/or styrene mixtures and noise on the auditory system in humans employed in occupational settings. The search included peer-reviewed articles published in English language involving human volunteers spanning a 25-year period (1990–2015. Studies included peer review journals, case–control studies, and case reports. Animal studies were excluded. An initial search identified 40 studies. After screening for inclusion, 13 studies were retrieved for full journal detail examination and review. As a whole, the results range from no to mild associations between styrene exposure and auditory dysfunction, noting relatively small sample sizes. However, four studies investigating styrene with other organic solvent mixtures and noise suggested combined exposures to both styrene organic solvent mixtures may be more ototoxic than exposure to noise alone. There is little literature examining the effect of styrene on auditory functioning in humans. Nonetheless, findings suggest public health professionals and policy makers should be made aware of the future research needs pertaining to hearing impairment and ototoxicity from styrene. It is recommended that chronic styrene-exposed individuals be routinely evaluated with a comprehensive audiological test battery to detect early signs of auditory dysfunction. Keywords: auditory system, human exposure, ototoxicity, styrene

  11. Kinetic Aspects of the Direct Electrochemical Oxidation of p-Xylene ...

    African Journals Online (AJOL)

    2004-01-26

    Jan 26, 2004 ... substrate, or that the charge per mole passed through the cell should be 4 F, if the cell is to function 100% efficiently. In previous work12, the effect of solution conditions for the anodic oxidation of toluenes was examined, and the oxidation of. 4-t-butyltoluene to 4-t-butylbenzaldehyde dimethyl acetal13 was.

  12. Information draft on the development of air standards for toluene

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-01

    Toluene is a colorless, volatile liquid with a benzene-like odour. Its predominant use is in the production of benzene, as an octane enhancer in gasoline, as a solvent in aerosol spray paints, wall paints, lacquers, inks, adhesives, resins, and in such consumer products as spot removers, paint strippers, cosmetics, perfumes and antifreezes. Approximately 150 Ontario industrial sources reported toluene releases to the air totaling 4,245 to 5,300 tonnes during the reporting years from 1993 to 1996, making toluene one of the top pollutants by release quantities in Ontario and Canada for all these years. It is absorbed via the lungs and the gastrointestinal tract, both in humans and animals. Once absorbed, it tends to accumulate in the fatty tissues, and in vascularized tissues such as nerve cells and brain tissue. Toluene adversely affects the central nervous system (CNS) of humans and experimental animals. Observed symptoms in exposed humans range from decrease in psychometric performance, to headache, intoxication, convulsions, narcosis and death. Health Canada concluded that toluene is unlikely to be carcinogenic, although the available data is insufficient for definite classification. Ontario has 24-hour ambient air quality criterion and a half-hour Point of Impingement standard for toluene of 2,000 microgram/cubic meter, based on odour effects. The US Environmental Protection Agency inhalation reference concentration (also adopted by most of the American states) is 400 microgram/cubic meter. The WHO recommended a guideline value of 7500 microgram/cubic meter. Health Canada And Environment Canada established a tolerable concentration of 3750 microgram/cubic meter. 69 refs., 2 tabs., appendix

  13. Investigation of mechanisms of polycyclic aromatic hydrocarbons (PAHs) initiated from the thermal degradation of styrene butadiene rubber (SBR) in N2 atmosphere.

    Science.gov (United States)

    Kwon, Eilhann; Castaldi, Marco J

    2008-03-15

    This study has been carried out to characterize the thermal decomposition of styrene-butadiene rubber (SBR), using thermogravimetric analysis (TGA) coupled to online GC/MS, and to investigate the formation and ultimate fate of chemical species produced during gasification of SBR. A preliminary mechanistic understanding has been developed to explain the formation and relationship of light hydrocarbons (C1-C4), substituted aromatics, and polycyclic aromatic hydrocarbons (PAHs) during the decomposition of SBR in a N2 atmosphere. Identification and absolute concentrations of over 50 major and minor species (from hydrogen to benzo[ghi]perylene) have been established, and the measurements have been carried out between 300 and 500 at 10 degrees C/min heating rate in a N2 atmosphere. The concentration of styrene reached 120 PPMV and the concentration of other substituted aromatics, such as toluene and ethyl benzene reached 20 and 5 PPMV, respectively. These measurements indicate PAH formation at a relatively lower temperature as compared to conventional fuel, such as coal and diesel. The PAH sequence is not simply the constructing of larger PAHs from smaller ones to achieve the complex polymer structures. It is possible to generate large PAH molecules while circumventing the typical construction pathway.

  14. Radioluminescence quenching of toluene scintillators by methyl methacrylate

    International Nuclear Information System (INIS)

    Polacki, Z.

    1985-01-01

    It was established that singlet electronic excited state of toluene is quenched by methyl methacrylate (MMA) but not by PMMA. The value of quenching rate constant ksub(q)=0,6x10sup(9) 1.molsup(-1).ssup(-1) indicates that the quenching is a diffusion controlled process. It is assumed that the excitation energy of toluene sensitizes the polymerization process of MMA. The increase of radioluminescence intensity and quantum yield of excitation energy transfer is the result of diminishing the quantity of MMA in the solution during polymerization time. (author)

  15. Dynamics and the Regiochemistry of Nitration of Toluene.

    Science.gov (United States)

    Nieves-Quinones, Yexenia; Singleton, Daniel A

    2016-11-23

    The regiochemistry of the nitration of toluene by NO 2 + BF 4 - in dichloromethane is accurately predicted from trajectories in explicit solvent. Simpler models and approaches based on transition state theory fail to account for the selectivity. Potential of mean force calculations find no free-energy barrier for reaction of the toluene/NO 2 + BF 4 - encounter complex, yet the trajectories require an extraordinary 3 ps to descend an exergonic slope. The selectivity is decided late in long trajectories because their completion requires solvent and counterion reorganization. The normal descriptive understanding of the regiochemistry based on transition-state energies is unsupported.

  16. Antipyrine clearance during experimental and occupational exposure to toluene

    DEFF Research Database (Denmark)

    Døssing, M; Bælum, Jesper; Lundqvist, G R

    1983-01-01

    Exposure to toluene vapour enhances hepatic microsomal enzyme function in animals as assessed by the metabolism of the test drug antipyrine. Thirty six printing trade workers with long term occupational exposure to a mixture of organic solvents and 39 matched controls were randomly allocated...... clearance 12 printing trade workers with 17 years (median) of occupational exposure to toluene vapour at concentrations of about 100 ppm were investigated before and four weeks after cessation of exposure. No difference in antipyrine clearance was found either within the groups or between the groups at any...

  17. Morphology-properties relationship on nanocomposite films based on poly(styrene-block-diene-block-styrene copolymers and silver nanoparticles

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available A comparative study on the self-assembled nanostructured morphology and the rheological and mechanical properties of four different triblock copolymers, based on poly(styrene-block-diene-block-styrene and poly(styrene-block-diene-block-styrene matrices, and of their respective nanocomposites with 1 wt% silver nanoparticles, is reported in this work. In order to obtain well-dispersed nanoparticles in the block copolymer matrix, dodecanethiol was used as surfactant, showing good affinity with both nanoparticles and the polystyrene phase of the matrices as predicted by the solubility parameters calculated based on Hoftyzer and Van Krevelen theory. The block copolymer with the highest PS content shows the highest tensile modulus and tensile strength, but also the smallest elongation at break. When silver nanoparticles treated with surfactant were added to the block copolymer matrices, each system studied shows higher mechanical properties due to the good dispersion and the good interface of Ag nanoparticles in the matrices. Furthermore, it has been shown that semiempirical models such as Guth and Gold equation and Halpin-Tsai model can be used to predict the tensile modulus of the analyzed nanocomposites.

  18. Evaluation of processing factors for selected organic contaminants during virgin olive oil production: Distribution of BTEXS during olives processing.

    Science.gov (United States)

    López-Blanco, Rafael; Gilbert-López, Bienvenida; Rojas-Jiménez, Rubén; Robles-Molina, José; Ramos-Martos, Natividad; García-Reyes, Juan F; Molina-Díaz, Antonio

    2016-05-15

    The presence of BTEXS (benzene, toluene, ethylbenzene, xylenes and styrene) in virgin olive oils can be attributed to environmental contamination, but also to biological processes during oil lipogenesis (styrene). In this work, the processing factor of BTEXS from olives to olive oil during its production was evaluated at lab-scale with an Abencor system. Benzene showed the lowest processing factor (15%), whereas toluene and xylenes showed an intermediate behavior (with 40-60% efficiency), and ethylbenzene and styrene were completely transferred (100%). In addition, an attempt to examine the contribution of potential sources to olives contamination with BTEXS was carried out for the first time. Two types of olives samples were classified according to their proximity to the contamination source (road). Although higher levels of BTEXS were found in samples close to roads, the concentrations were relatively low and do not constitute a major contribution to BTEXS usually detected in olive oil. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Removal of butylacetate and xylene from air by electron beam a product study

    Science.gov (United States)

    Hirota, K.; Woletz, K.; Paur, H.-R.; Mätzing, H.

    1995-09-01

    VOC emissions from industrial processes can cause hazardous impacts on the environment through increased ozone and smog formation. Previously, it was demonstrated that the electron beam technology is a powerful tool to scrub small amounts of VOC from large volume flows at ambient temperature. In this paper, product analyses are presented for the removal of common aliphatic and aromatic hydrocarbons from air. Butylacetate and xylene were added to an air stream of 1000 Nm3/h at concentration levels close to 100 mg C/Nm3, and irradiated with 550 keV electrons at the AGATE-2 pilot plant of KfK. The removal efficiencies were measured by FID and GC in the dose range 0-10 kGy. The removal efficiency of xylene was found to be close to 90% at 10 kGy which is almost twice as high as that of butylacetate. Three types of products were measured quantitatively by wet chemical analysis, filtration, and FTIR:organic acids (formic, acetic, propionic, butyric acid) aerosol inorganic products and by-products (CO, CO2, O3, NOX) The major product obtained from xylene irradiation was a particulate matter with a molecular C/O ratio close to 1.5. No aerosol formation was observed in case of butylacetate, the major irradiation product of which was acetic acid. Less than 15% of the removed carbon were converted to CO and CO2 in both cases. The total carbon balance was 95 ± 15% in all experiments. By model calculation with the AGATE-code, the removal efficiencies and product distributions can be interpreted starting from OH radical attack on the hydrocarbon molecules and subsequent mechanisms which are known from atmospheric chemistry.

  20. Simulation chamber studies of the atmospheric degradation of xylene oxidation products

    Science.gov (United States)

    Clifford, G.; Rea, G.; Thuener, L.; Wenger, J.

    2003-04-01

    Aromatic compounds are emitted to the atmosphere from their use in automobile fuels and solvents. In addition to being important primary pollutants, many aromatics, including the xylenes, possess high photochemical reactivity and make a major contribution to the formation of oxidants, such as ozone and nitrates, in the troposphere. The atmospheric oxidation of aromatics produces a wide variety of products and the atmospheric reactivity of many of these species is unknown. The aim of this work was to study the atmospheric degradation processes for dimethylphenols, tolualdehydes and dicarbonyl compounds which are produced from the hydroxyl radical initiated oxidation of the xylenes. Experiments on the hydroxyl (OH) and nitrate radical initiated oxidation of dimethylphenols and tolualdehydes have been performed in a large atmospheric simulation chamber in our laboratory. The chamber is made of FEP foil and has a volume of about 4750 litres. It is equipped with gas chromatography, GC-MS, and in situ FTIR spectroscopy for chemical analysis and a scanning mobility particle sizer for aerosol measurements. Rate coefficients have been determined for the reactions of hydroxyl and nitrate radicals with dimethylphenols and tolualdehydes. Gas-phase products and the yield of secondary organic aerosol have also been determined for the OH-initiated oxidation of these compounds. Mechanisms for the formation of the products are proposed. The photolysis of the unsaturated dicarbonyls, butenedial and 4-oxo-pent-2-enal, has been studied using real sunlight at the European Photoreactor (EUPHORE) in Valencia, Spain. Photolysis rates were measured and indicate that photolysis by sunlight is the major atmospheric degradation process for these compounds. Product studies show the formation of a ketene intermediate that decays to form five membered ring compounds such as furanones and maleic anhydride. Mechanisms for the formation of the products are proposed. Finally, the data obtained in

  1. FORMATION OF POLYKETONES IN IRRADIATED TOLUENE/PROPYLENE/NOX/AIR MIXTURES

    Science.gov (United States)

    A laboratory study was carried out to investigate the formation of polyketones in secondary organic aerosol from photooxidation of the aromatic hydrocarbon toluene, a major constituent of automobile exhaust. The laboratory experiments consisted of irradiating toluene/propylene...

  2. Metabolic interaction between toluene, trichloroethylene and n-hexane in humans

    DEFF Research Database (Denmark)

    Bælum, Jesper; Mølhave, Lars; Hansen, S H

    1998-01-01

    This human experimental study describes the mutual metabolic interaction between toluene, trichloroethylene, and n-hexane.......This human experimental study describes the mutual metabolic interaction between toluene, trichloroethylene, and n-hexane....

  3. MESOMORPHIC STATE OF POLY(VINYLPYRIDINE)-DODECYLBENZENESULFONIC ACID COMPLEXES IN BULK AND IN XYLENE SOLUTION

    OpenAIRE

    Ikkala, O.; Ruokolainen, J.; ten Brinke, G.; Torkkeli, M.; Serimaa, R.

    1995-01-01

    Theoretically, lyotropic behavior of flexible polymers can be induced by associating the polymers with a large amount of long-tail surfactants leading to bottle-brush type conformations in suitable solvents. To address this and related questions, complexes of poly(2-vinylpyridine) (P2VP) and poly(4-vinylpyridine) (P4VP) with p-dodecylbenzenesulfonic acid (DBSA), characterized by FT-IR, were investigated in the bulk and in xylene, i.e., a good solvent for the alkyl side chains. At a 1:1 molar ...

  4. Modelling toluene oxidation : Incorporation of mass transfer phenomena

    NARCIS (Netherlands)

    Hoorn, J.A.A.; van Soolingen, J.; Versteeg, G. F.

    The kinetics of the oxidation of toluene have been studied in close interaction with the gas-liquid mass transfer occurring in the reactor. Kinetic parameters for a simple model have been estimated on basis of experimental observations performed under industrial conditions. The conclusions for the

  5. Electrocardiographic effects of toluene in the anesthetized rat.

    Science.gov (United States)

    Vidrio, H; Magos, G A; Lorenzana-Jimenez, M

    1986-01-01

    The influence of inhalation of near lethal quantities of toluene on some ECG parameters, as well as the possible cardiac sensitizing effect of the solvent, were determined in chloralose-anesthetized rats. These actions were compared with those of its close analogue benzene. Both solvents produced tachycardia; toluene increased the duration of QRS and specially PR, while benzene decreased P wave duration. No other systematic changes in ECG morphology or evidence of arrhythmia were observed. Toluene appeared to decrease the number of ectopic beats induced by epinephrine, in contrast to benzene, which increased it markedly. These results suggest that toluene administered by inhalation up to near lethal doses is devoid of untoward ECG effect in the chloralose-anesthetized rat, its only action being a decrease in intraventricular and particularly AV conduction. It does not share the myocardial sensitizing properties of benzene and in fact appears to elicit some protection from the arrhythmogenic effects of epinephrine, although no definite conclusions as to this action can be derived due to limitations in the experimental model used.

  6. Fenton-like initiation of a toluene transformation mechanism

    Science.gov (United States)

    In Fenton-driven oxidation treatment systems, reaction intermediates derived from parent compounds can play a significant role in the overall treatment process. Fenton-like reactions in the presence of toluene or benzene, involved a transformation mechanism that was highly effici...

  7. Gas phase toluene isopropylation over high silica mordenite

    Indian Academy of Sciences (India)

    Administrator

    phenols, fragrances, pharmaceuticals, herbicides, heat transfer media, etc. The alkylation of toluene over zeolites is normally considered to follow the well-known Friedel–Crafts mechanism which evidently proceeds by direct ortho-para attack of the ring followed by positional isomerisation producing the meta isomer. 1,2.

  8. Effects of Toluene on Some Physicochemical Parameters of The ...

    African Journals Online (AJOL)

    Reproductive success analysis showed a decrease in hatching success across the concentrations and high mortality of eggs with increased concentration. The control had 36.6% hatching success, while ... treated before released into the environment. Keywords: effect, toluene, catfish, growth, reproductive, performance.

  9. Instrument for benzene and toluene emission measurements of glycol regenerators

    International Nuclear Information System (INIS)

    Hanyecz, Veronika; Szabó, Gábor; Mohácsi, Árpád; Puskás, Sándor; Vágó, Árpád

    2013-01-01

    We introduce an in-field and in-explosive atmosphere useable instrument, which can measure the benzene and toluene concentration in two gas and two glycol samples produced by natural gas dehydration units. It is a two-phase, on-line gas chromatograph with a photoacoustic spectroscopy based detector. The time resolution is 10 min per cycle and the minimum detectable concentrations are 2 mg m −3 for benzene, 3 mg m −3 for toluene in natural gas, and 5 g m −3 for benzene and 6 g m −3 for toluene in glycol. Test measurements were carried out at a dehydration plant belonging to MOL Hungarian Oil and Gas Company. Benzene and toluene emissions of gas dehydration unit are calculated from the measured values based on mass balance of a glycol regenerator. The relationship between the outdoor temperature and the measured concentration was observed which is caused by temperature-dependent operation of the whole dehydration unit. Emission decreases with increase of outdoor temperature. (paper)

  10. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    Science.gov (United States)

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  11. Gas phase toluene isopropylation over high silica mordenite

    Indian Academy of Sciences (India)

    Mordenite (HM) catalysts with three different Si/Al ratios were compared for their activity and selectivities in gas phase toluene isopropylation with isopropanol. Catalyst with Si/Al ratio 44.9 offered better cumene selectivity, hence, it was chosen for detailed kinetic investigations. The influence of various process parameters ...

  12. Isolation and characterization of a novel toluene-degrading, sulfate-reducing bacterium.

    OpenAIRE

    Beller, H R; Spormann, A M; Sharma, P K; Cole, J R; Reinhard, M

    1996-01-01

    A novel sulfate-reducing bacterium isolated from fuel-contaminated subsurface soil, strain PRTOL1, mineralizes toluene as the sole electron donor and carbon source under strictly anaerobic conditions. The mineralization of 80% of toluene carbon to CO2 was demonstrated in experiments with [ring-U-14C]toluene; 15% of toluene carbon was converted to biomass and nonvolatile metabolic by-products, primarily the former. The observed stoichiometric ratio of moles of sulfate consumed per mole of tolu...

  13. Removal of styrene from waste gas stream using a biofilter

    Directory of Open Access Journals (Sweden)

    B Bina

    2004-12-01

    Full Text Available Background: Styrene is produced in large quantities in the chemical industries and it has been listed among the 189 hazardous and toxic atmospheric contaminants under Clean Air Act Amendments, 1990, due to its adverse effects on human health. The biofiltration has been widely and efficiently applied during recent decades for the treatment of air streams contaminated by volatile organic compounds at low concentrations. Also this technology has been applied widely and efficiently in the removal of styrene from waste gas streams. Methods: Biofiltration of waste gas stream polluted by styrene vapor was investigated in a three-stage bench scale reactor. Yard waste compost using shredded hard plastics as a bulking agent in a 75:25 v/v mix of plastics:compost was used to packing biofilter. The system inoculation was achieved by adding thickened activated sludge obtained from municipal wastewater treatment plant and the effects of loading rate, inlet concentration, and empty bed retention time variations on the performance and operation of biofilter were studied. Results: Microbial acclimation to styrene was achieved with inlet concentration of 65 ± 11 ppm and bed contact time of 360 s after 57 days of operation. Under steady state conditions experimental results showed equal average removal efficiency of about 84% at loading rates of 60 and 80 g m-3 h-1 with empty bed retention time of 60 s. Maximum elimination capacity was obtained up to 81 g m-3 h-1 with organic loading rate of about 120 g m-3 h-1. Reduction in performance was observed at inlet concentrations of upper than 650 ppm related to organic loading rates up to 160 g m-3 h-1 and then removal efficiency was decreased sharply. Evaluation of the concentration profile along the bed height of column indicated that the most value of elimination capacity occurred in the first section of biofilter. Elimination capacity also showed higher performance when empty bed retention time was reduced to 30 s

  14. Crystallization analysis fractionation of poly(ethylene-co-styrene) produced by metallocene catalysts

    KAUST Repository

    Kamal, Muhammad Shahzad

    2013-06-06

    Ethylene homo polymer and ethylene-styrene copolymers were synthesized using Cp2ZrCl2 (1)/methyl aluminoxane (MAO) and rac-silylene-bis (indenyl) zirconium dichloride (2)/MAO catalyst systems by varying styrene concentration and reaction conditions. Crystallization analysis fractionation (CRYSTAF), DSC, FTIR and 1H NMR spectroscopy were used for characterizing the synthesized polymers. Interestingly, styrene was able to increase the activity of 1/MAO and 2/MAO catalyst systems at low concentrations, but at higher concentrations the activity decreases. The 1/MAO system at low and high pressure was unable to incorporate styrene, and the final product was pure polyethylene. On the other hand, with 2/MAO polymerization of ethylene and styrene yielded copolymer containing both styrene and ethylene. Results obtained from CRYSTAF and DSC reveal that on using 1/MAO system at high pressure, the resulting polymer in the presence of styrene has similar crystallinity as the polymer produced without styrene. Using both 1/MAO at low pressure and 2/MAO leads to decrease in crystallinity with increase in styrene concentration, even though the former does not incorporate styrene. © 2013 Springer-Verlag Berlin Heidelberg.

  15. Tentative criteria for assessing workers exposure to toluene by urinary toluene screening.

    Science.gov (United States)

    Asakawa, Fumiyuki; Hirao, Tomohiro; Suna, Shigeru; Kureha, Akinori; Jitsunari, Fumihiko

    2006-04-01

    This study assessed screening thresholds for determining workers exposure to toluene (Tol) by urinary Tol (Tol-U) and proposed applicable criteria for on-site settings. Participants' urine samples (n = 21) were collected at the end of the workday during the latter half of a week and the Tol-U concentration was assayed. Simultaneously, each worker's exposure dose to Tol in the breathing zone during work, Tol-TWA (time-weighted average), was measured. Tentative criteria were proposed. Level I, less than Tol-U 38 microg/l, has the least chance of exceeding Tol-OEL 50 ppm (occupational exposure limit for Tol recommended by the Japan Society for Occupational Health), probability 95% <. Level II, Tol-U 38-60 microg/l, has a low possibility of exceeding Tol-OEL. Level III, Tol-U 60-110 microg/l, has a high possibility of exceeding Tol-OEL. Level IV, more than Tol-U 110 microg/l, clearly exceeds Tol-OEL, probability 95% <.

  16. Styren a styren-7,8-oxid:metabolismus a analytické metody stanovení aduktů s proteiny

    Czech Academy of Sciences Publication Activity Database

    Jágr, Michal; Pacáková, V.; Petříček, Miroslav

    2009-01-01

    Roč. 103, č. 11 (2009), s. 902-910 ISSN 0009-2770 Institutional research plan: CEZ:AV0Z50200510 Keywords : styren * adducts * styren-7,8-oxid Subject RIV: EE - Microbiology, Virology Impact factor: 0.717, year: 2009

  17. Transport and biodegradation of toluene in unsaturated soil

    Science.gov (United States)

    Jin, Yan; Streck, Thilo; Jury, William A.

    1994-12-01

    Degradation of volatile organic chemicals during transport has received little attention in the past. In this study we report the results of a series of experiments on toluene movement through soil columns of different length in sterilized, pre-exposed and unexposed soil. Toluene was added to 25-cm-diameter soil columns through an inlet chamber that maintained a constant concentration throughout the experiment. The toluene diffused through the soil to an outlet chamber at the top which was continuously swept with humidified air and samples were periodically analysed to determine toluene flux. The first experiment, conducted under sterilized conditions, was used to measure the soil gas diffusion coefficient, and subsequent experiments in which biodegradation occurred were used to estimate the degradation rate coefficient by fitting the outflow to a mathematical model. The degradation rate was very rapid under both pre-exposed and unexposed soil conditions, corresponding to a half-life of ˜ 2 h when bacterial activity reached high levels. Prior to this stage, the volatilization flux was very erratic, implying that growth rates of the bacteria were out of phase with the transport process. Overall, the degradation process was not well described by a first-order model until the population stabilized. Pre-exposure of the soil to the substrate prior to the transport experiment greatly increased the rate of removal of toluene during transport. Under such conditions, a 30-cm cover could virtually stop volatization losses of the compound when the inlet concentration was well below saturation, and could decrease it by a factor of ⩾30 even when the inlet concentration was saturated.

  18. Immunologic and renal markers among photogravure printers exposed to toluene.

    Science.gov (United States)

    Stengel, B; Cénée, S; Limasset, J C; Diebold, F; Michard, D; Druet, P; Hémon, D

    1998-08-01

    This study assessed immunologic and early renal effects of chronic toluene exposure. In a longitudinal study of 92 printers and 74 referents, 145 subjects had pre- and poststudy samples of blood and urine taken for the following measurements: immunoglobulin E (IgE), antiglomerular basement membrane (anti-GBM) and antilaminin (anti-LAM) antibodies in blood; creatinine and beta2-microglobulin in blood and urine; and microalbumin, N-acetyl-b-D-glucosaminidase (NAG) and alanine-aminopeptidase in urine. Creatinine clearance was calculated according to the Cockroft-Gault formula. Eight-hour personal air samples were collected twice to assess present exposure to toluene. A job-exposure matrix was developed to estimate past cumulative exposure. Information about potential confounders was recorded by questionnaire. Multiple regression analysis was performed to study dose-effect relations adjusted for age and smoking. No subject was positive for anti-GBM antibodies, and only 12 were positive for anti-LAM. No relation was observed between the markers studied and present exposure to toluene except that creatinine clearance was higher among the exposed subjects than among the referents. A dose-response relation was observed between cumulative toluene exposure and both IgE and NAG excretion. No interaction was observed between hypertension and exposure, but the relationship with NAG did not persist when subjects with hypertension were excluded. Past or present exposure did not alter the 2-year trend of any marker studied. According to the results of this study, toluene at 50 ppm is not related to detectable renal dysfunction. The increased IgE levels associated with present and past exposure require further investigation.

  19. TrgI, toluene repressed gene I, a novel gene involved in toluene-tolerance in Pseudomonas putida S12

    NARCIS (Netherlands)

    Volkers, R.J.M.; Ballerstedt, H.; Ruijssenaars, H.; Bont, J.A.M. de; Winde, J.H. de; Wery, J.

    2009-01-01

    Pseudomonas putida S12 is well known for its remarkable solvent tolerance. Transcriptomics analysis of this bacterium grown in toluene-containing chemostats revealed the differential expression of 253 genes. As expected, the genes encoding one of the major solvent tolerance mechanisms, the solvent

  20. Production and characterization of poly(styrene-co-methylmethacrylate)

    International Nuclear Information System (INIS)

    Augustinho, Tiago R.; Coan, Thais; Abarca, Silvia A.C.; Testoni, Alex A.S.; Baumgarten, Bruno P.; Machado, Ricardo A.F.

    2009-01-01

    Polystyrene (PS) is a polymer used in diverse industrial segments. It is easy to process and has a low cost when compared to other materials. However, PS has low mechanical resistance, which limits its application in some areas. Thus, a methodology that is sufficiently used is the synthesis of a copolymer, formed of two or more monomers to get products that have characteristics that are not possible to obtain with only one monomer. In this work, the styrene and methyl methacrylate monomers had been carried through reactions of copolymerization by means of polymerization in suspension using (MMA) with styrene in a bigger percentage. MMA was selected for being a monomer that results in a polymeric configuration more resistant than the PS. The copolymerization was proven to occur by infra-red spectroscopy (IR) and Nuclear Magnetic Resonance (NMR). Different analyses were performed using different initiators, weight molar and conversion studies. (author)

  1. Effect of ultrasonic pretreatment on emulsion polymerization of styrene.

    Science.gov (United States)

    Nagatomo, Daichi; Horie, Takafumi; Hongo, Chizuru; Ohmura, Naoto

    2016-07-01

    This study investigated the effect of pretreatment of ultrasonic irradiation on emulsion polymerization of styrene to propose a process intensification method which gives high conversion, high reaction rate, and high energy efficiency. The solution containing styrene monomer was irradiated by a horn mounted on the ultrasonic transducer with the diameter of 5mm diameter and the frequency of 28 kHz before starting polymerization. The pretreatment of ultrasound irradiation as short as 1 min drastically improved monomer dispersion and increased reaction rate even under the agitation condition with low rotational speed of impeller. Furthermore, the ultrasonic pretreatment resulted in higher monomer concentration in polymer particles and produced larger polymer particles than conventional polymerization without ultrasonic pretreatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Fall From High and Acute Styrene Exposure : A Case Report

    Directory of Open Access Journals (Sweden)

    Ferhat Ižcme

    2016-01-01

    Full Text Available Styrene is a benzene derivative of the aromatic hydrocarbon which is widely used in the manufacture of plastics industry, synthetic rubber and insulating materials. Its toxic effects occur by inhalation of its vapor or by direct contact. In acute intoxication irritation in the eye and skin may occur and chemical pneumonitis may develop in the lungs due to inhalation. It dissolves in ethanol, benzene, acetone and ether. Water solubility is low. In this paper we present the management of a patient who after falling down from the scaffold which is approximately 5 meters of height, a tin of styrene on the same scaffold spilled on him and we would like to draw attention to the need for decontamination chamber which is not available in the most of the emergency departments in our country.

  3. Microwave-assisted nitroxide-mediated miniemulsion polymerization of styrene

    International Nuclear Information System (INIS)

    Li Jieai; Zhu Xiulin; Zhu Jian; Cheng Zhenping

    2007-01-01

    Nitroxide-mediated free-radical miniemulsion polymerizations (NMRPs) of styrene were successfully performed under microwave irradiation at 135 o C. The polymerizations proceeded in a controlled manner, yielding polymers that showed an incremental increase in molecular weight with conversion and had narrow molecular weight distributions. The resulting latexes were colloidally stable. The polymerization behavior, molecular weights of polymers and Z-average size of latex particles were also investigated under two different heating methods, microwave irradiation and conventional heating

  4. Moessbauer studies of styrene-acrylonitrile copolymers containing ferric chloride

    International Nuclear Information System (INIS)

    Brar, A.S.; Sekhar, M.S.

    1989-01-01

    Acrylonitrile-styrene (AN-St) copolymers of different compositions were prepared, with and without ferric chloride by free radical polymerization. It was found using Moessbauer spectroscopy that reduction of Fe 3+ to Fe 2+ took place during the polymerization. The addition of ferric chloride and the reduction of Fe 3+ was found to influence the thermal stability of the copolymers. (author) 6 refs.; 3 figs

  5. Interacting Blends of Novel Unsaturated Polyester Amide Resin with Styrene

    OpenAIRE

    Patel, Hasmukh S.; Panchal, Kumar K.

    2004-01-01

    Novel unsaturated poly (ester-amide) resins (UPEAs) were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA) and unsaturated aliphatic bisamic acids using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, Styrene (STY.) to produce a homogeneous resin syrup. The curing of these UPEAs-STY. resin blends was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored by using a differential scanning calorimeter ...

  6. Beyond benzyl grignards: facile generation of benzyl carbanions from styrenes.

    Science.gov (United States)

    Grigg, R David; Rigoli, Jared W; Van Hoveln, Ryan; Neale, Samuel; Schomaker, Jennifer M

    2012-07-23

    Benzylic functionalization is a convenient approach towards the conversion of readily available aromatic hydrocarbon feedstocks into more useful molecules. However, the formation of carbanionic benzyl species from benzyl halides or similar precursors is far from trivial. An alternative approach is the direct reaction of a styrene with a suitable coupling partner, but these reactions often involve the use of precious-metal transition-metal catalysts. Herein, we report the facile and convenient generation of reactive benzyl anionic species from styrenes. A Cu(I)-catalyzed Markovnikov hydroboration of the styrenic double bond by using a bulky pinacol borane source is followed by treatment with KOtBu to facilitate a sterically induced cleavage of the C-B bond to produce a benzylic carbanion. Quenching this intermediate with a variety of electrophiles, including CO(2), CS(2), isocyanates, and isothiocyanates, promotes C-C bond formation at the benzylic carbon atom. The utility of this methodology was demonstrated in a three-step, two-pot synthesis of the nonsteroidal anti-inflammatory drug (±)-flurbiprofen. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Styrene biofiltration in a trickle-bed reactor

    Directory of Open Access Journals (Sweden)

    V. Novak

    2008-04-01

    Full Text Available The biological treatment of styrene waste gas in a trickle-bed filter (TBF was investigated. The bioreactor consisted of a two-part glass cylinder (ID 150 mm filled with 25 mm polypropylene Pall rings serving as packing material. The bed height was 1m. Although the laboratory temperature was maintained at 22 ºC, the water temperature in the trickle-bed filter was slightly lower (about 18 ºC.The main aim of our study was to observe the effect of empty-bed residence time (EBRT on bioreactor performance at a constant pollutant concentration over an extended time period. The bioreactor was inoculated with a mixed microbial consortium isolated from a styrene-degrading biofilter that had been running for the previous two years. After three weeks of acclimation period, the bioreactor was loaded with styrene (100 mg.m-3. EBRT was in the range of 53 s to 13 s. A maximum elimination capacity (EC of 11.3 gC.m-3.h-1 was reached at an organic loading (OL rate of 18.6 gC.m-3.h-1.

  8. Modelling of toluene biodegradation and biofilm growth in a fixed biofilm reactor

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1992-01-01

    which grow relatively fast and detach easily, leading to a biomass growth delayed with respect to substrate degradation. The non-filamentous bacteria inside the biofilm also degrade toluene but with a slower rate compared to the filamentous bacteria. Because the nonfilamentous bacteria do not detach...... with toluene degradation was successfully modelled as well as the decay phase when toluene addition was turned off. In addition to this, modelling of toluene removal and oxygen consumption versus toluene concentration in the reactor was performed. This required consideration of inhibition of substrate...

  9. Reno and Hepatoprotective Activity of Buffalo’s Milk Against Xylene-Induced Toxicity in the Rat

    Directory of Open Access Journals (Sweden)

    Massumeh Ahmadizadeh

    2016-10-01

    Full Text Available Background Xylene is widely used in the industry and medical technology as a solvent, besides occupational exposure. It has the potential to be toxic in humans and animals. Objectives The present study was carried out to determine the protective effects of buffalo’ milk (BM against xylene-induced liver and kidney damage. Methods A total 42 male rats were randomly assigned into 7 groups. The rats in group I was the control . Groups II, III and IV were received 1 mL distilled water ten minutes prior to administration of xylene (X at doses of 0.81, 0.162 and 0.324 mmole/kg. Rats in groups of V,VI and VII were received 1mL buffalo’s milk 10 minutes prior to administration of X ( ip at doses of 0.81, 0.162 and 0.324 mmole/kg. The experiment repeated for 7 consecutive days. 24 hours after last administrations, all animals were killed with an overdose of sodium pentobarbital. The blood was then collected for determination of biochemical tests including alanine aminotransferase (ALT,aspartate aminotransferase (AST,alkaline phosphatase (ALP,blood urea nitrogen (BUN,creatinine (CR,catalase (CAT,superoxide dismutase (SOD and glutathione (GSH. The liver and kidney tissues were removed, fixed and processed for light microscopy. Results Biochemical analyses indicated a significant decline in the activities of SOD, CAT and GSH level and markedly increased ALT, AST, ALP, BUN, CR when compared to those in non-treated rats (control. Dose-dependent injuries in rat liver and kidneys were also observed in xylene treated rats. Buffalo’s milk protected all biochemical parameters against xylene-induced toxicity. It also protected liver and kidney tissues against xylene produced cell damage. Conclusions The results of this study supports the view that xylene induces liver and kidney injury. Buffalo’s milk has potential to protect liver and kidney against xylene toxicity

  10. Dynamic Response of Acrylonitrile Butadiene Styrene Under Impact Loading (Open Access)

    Science.gov (United States)

    2016-03-16

    ORIGINAL ARTICLE Open Access Dynamic response of acrylonitrile butadiene styrene under impact loading Gbadebo Owolabi1*, Alex Peterson1, Ed Habtour2...Tensile tests were conducted on 3-D printed acrylonitrile butadiene styrene (ABS) at differentstrain rates, according to the ASTM D638 standard, to assess... butadiene styrene, High strain rates, Dynamic response Background Through the use of direct digital manufacturing (DDM), more commonly known as

  11. Characterization of a Poly(styrene-block-methylacrylate-random-octadecylacrylate-block-styrene) Shape Memory ABA Triblock Copolymer

    Science.gov (United States)

    Fei, Pengzhan; Cavicchi, Kevin

    2011-03-01

    A new ABA triblock copolymer of poly(styrene-block- methylacrylate-random-octadecylacrylate-block-styrene) (PS-b- PMA-r-PODA-b-PS) was synthesized by reversible addition fragmentation chain transfer polymerization. The triblock copolymer can generate a three-dimensional, physically crosslinked network by self-assembly, where the glassy PS domains physically crosslink the midblock chains. The side chain crystallization of the polyoctadecylacrylare (PODA) side chain generates a second reversible network enabling shape memory properties. Shape memory tests by uniaxial deformation and recovery of molded dog-bone shape samples demonstrate that shape fixities above 96% and shape recoveries above 98% were obtained for extensional strains up to 300%. An outstanding advantage of this shape memory material is that it can be very easily shaped and remolded by elevating the temperature to 140circ; C, and after remolding the initial shape memory properties are totally recovered by eliminating the defects introduced by the previous deformation cycling.

  12. Bacterial degradation of styrene in waste gases using a peat filter

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, M.; Reittu, A. [Kuopio Univ. (Finland). Dept. of Environmental Sciences; Wright, A. von; Suihko, M.L. [VTT Biotechnology and Food Research (Finland); Martikainen, P.J. [Kuopio Univ. (Finland). Dept. of Environmental Sciences]|[National Public Health Inst., Lab. of Environmental Microbiology, Kuopio (Finland)

    1997-12-31

    A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m{sup -3} h{sup -1} (max. 30 g m{sup -3} h{sup -1}). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 C, but the styrene removal was still satisfactory at 12 C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the {gamma} group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health points of view. (orig.)

  13. The function of a toluene-degrading bacterial community in a waste gas trickling filter

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Arvin, E.

    1999-01-01

    ) during two weeks. In spite of the low fraction in the biofilm, the toluene degraders supported growth of the dominating part of non-toluene-degrading heterotrophs in the biofilm, as toluene was the sole carbon source supplied to the system. The maximum intrinsic growth rate of P. putida in the biofilm......The function of a community of toluene-degrading bacteria in a biofilm system was investigated with regard to growth and toluene degradation in order to investigate substrate interactions in the community. This was done by the combination of experimental observations using a specific...... and the activity of P. putida, a representative of the toluene-degrading species in the biofilm which have been described previously (Pedersen et al., 1997) were simulated. The simulation indicated that the volume fraction of the toluene degraders in the biofilm decreased from 12% to only 2% (11% of dry weight...

  14. Morphology and Phase Transitions in Styrene-Butadiene-Styrene Triblock Copolymer Grafted with Isobutyl-Substituted Polyhedral Oligomeric Silsesquioxanes

    Energy Technology Data Exchange (ETDEWEB)

    Drazkowski, Daniel B.; Lee, Andre; Haddad, Timothy S. (ERC, Inc.); (MSU)

    2008-10-03

    Two symmetric triblock polystyrene-butadiene-polystyrene (SBS) copolymers with different initial morphologies were grafted with varying amounts of isobutyl-substituted polyhedral oligomeric silsesquioxane (POSS) molecules. The POSS octamers, R{prime}R{sub 7}Si{sub 8}O{sub 12}, were designed to contain a single silane functional group, R{prime}, which was used to graft onto the dangling 1,2-butadienes in the polybutadiene block and seven identical organic groups, R = isobutyl (iBu). Morphology and phase transitions of these iBu-POSS-modified SBS were investigated using small-angle X-ray scattering and rheological methods. It was observed that when iBu-POSS was grafted to the butadiene segment, the long-range and local order of the morphology were preserved, and the d-spacing showed a small, systematic increase with increasing POSS content. These observations suggest that grafted iBu-POSS were well-distributed within the butadiene domains and did not interact with the styrene domains; effectively, grafting of iBu-POSS to butadiene did not affect the segregation between butadiene and styrene domains. However, addition of iBu-POSS reduces the overall polystyrene volume. Consequently, from a morphology standpoint, this modification effectively shifts the phase diagram to lower styrene content. This was supported with SAXS and transition temperatures measurements made from the different host morphologies.

  15. Toluene metabolism during exposure to varying concentrations combined with exercise

    DEFF Research Database (Denmark)

    Bælum, Jesper; Døssing, M; Hansen, S H

    1987-01-01

    . In Study A, four males were exposed to clean air and to constant and varying concentrations of toluene in combination with rest and with 100 W exercise in 140 min. Exercise increased end exposure excretion rate of HA and O-cr by 47 and 114%, respectively. After exposure, all excess HA was excreted within 4...... between the exposure schedules. In Study B, 32 males and 39 females aged between 31 and 50 years were exposed once to either clean air, constant or varying concentrations of toluene. Background excretion rate of HA was 0.97 +/- 0.75 mg/min (1.25 +/- 1.05 g/g creatinine) and rose to 3.74 +/- 1.40 mg/min (3...... implementing either of them as biological exposure indices, the influence of sex, body size, age as well as consumption of tobacco and alcohol has to be considered....

  16. Rare earth(3) nitrates extraction with trialkylmethylammonium nitrate in toluene

    International Nuclear Information System (INIS)

    Pyartman, A.K.; Kovalev, S.V.; Keskinov, V.A.; Khokhlova, N.V.

    1997-01-01

    Extraction of rare earth(3) nitrates [praseodymium(3)-lutetium(3)] with trialkylmethylammonium nitrate in toluene at T = 298.15 K and pH 2 is studied. Extraction isotherms are described with regard to formation of compounds of (R 4 N) i [Ln(NO 3 ) 3+i ] composition (i = 2, 3) in organic phase. Values of extraction constants are calculated, they are decreasing in the praseodymium(3) - lutetium(3) series

  17. Eco friendly nitration of toluene using modified zirconia

    Directory of Open Access Journals (Sweden)

    K.R. Sunaja Devi

    2013-03-01

    Full Text Available Nitration of toluene has been studied in the liquid phase over a series of modified zirconia catalysts.  Zirconia, zirconia- ceria (Zr0.98Ce0.02O2, sulfated zirconia and sulfated zirconia- ceria were synthesised by co precipitation method and were characterised by X-ray diffraction, BET surface area, Infra red spectroscopy analysis (FTIR, Thermogravimetric analysis (TGA, Scanning Electron Microscopy (SEM and Energy Dispersive X ray analysis (EDAX. The acidity of the prepared catalysts was determined by FTIR pyridine adsorption study. X-ray diffraction studies reveal that the catalysts prepared mainly consist of tetragonal phase with the crystallite size in the nano range and the tetragonal phase of zirconia is stabilized by the addition of ceria. The modified zirconia samples have higher surface area and exhibits uniform pore size distribution aggregated by zirconia nanoparticles. The onset of sulfate decomposition was observed around 723 K for sulfated samples. The catalytic performance was determined for the liquid phase nitration of toluene to ortho-, meta- and para- nitro toluene. The effect of reaction temperature, concentration of nitric acid, catalyst reusability and reaction time was also investigated. © 2013 BCREC UNDIP. All rights reservedReceived: 20th November 2012; Revised: 8th December 2012; Accepted: 7th January 2013[How to Cite: K. R. S. Devi, S. Jayashree, (2013. Eco friendly nitration of toluene using modified zirconia. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 205-214. (doi:10.9767/bcrec.7.3.4154.205-214][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4154.205-214 ] View in  |

  18. Deaths and tumours among rotogravure printers exposed to toluene.

    Science.gov (United States)

    Svensson, B G; Nise, G; Englander, V; Attewell, R; Skerfving, S; Möller, T

    1990-01-01

    A cohort of 1020 rotogravure printers exposed to toluene and employed for a minimum period of three months in eight plants during 1925-85 was studied. Air levels of toluene were available since 1943 in one plant and since 1969 in most. Based on these measurements and on present concentrations of toluene in blood and subcutaneous fat, the yearly average air levels in each plant were estimated. They reached a maximum of about 450 ppm in the 1940s and 1950s but were only about 30 ppm by the mid-1980s. Exposure to benzene had occurred up to the beginning of the 1960s. Compared with regional rates, total mortality did not increase during the observation period 1952-86 (129 observed deaths v 125 expected; SMR = 1.03). There was no increase in mortality from non-malignant diseases of the lungs, nervous system, or gastrointestinal and urinary tracts. There was no overall excess of tumours 1958-85 (68 v 54, SMR = 1.26; 95% confidence interval, CI = 0.95-1.7). Among the specific cancers, only those of the respiratory tract were significantly increased (16 v 9; SMR = 1.76, CI = 1.03-2.9). Statistical significance was not attained, however, when only subjects with an exposure period of at least five years and a latency period of at least 10 years were considered. Further, there were no dose response relations with cumulated toluene dose (ppm years). There were no significant increases of tumours at other sites, including leukaemias/lymphomas/myelomas. PMID:2378814

  19. Binary and ternary LLE data of the system (ethylbenzene + styrene + 1-ethyl-3-methylimidazolium thiocyanate) and binary VLE data of the system (styrene + 1-ethyl-3-methylimidazolium thiocyanate)

    International Nuclear Information System (INIS)

    Jongmans, Mark T.G.; Schuur, Boelo; Haan, André B. de

    2012-01-01

    Highlights: ► LLE data have been measured for the system {ethylbenzene + styrene + [EMIM][SCN]}. ► VLE was determined for the system {styrene + [EMIM][SCN]} at vacuum conditions. ► All experimental data were correlated well with the NRTL model. ► [EMIM][SCN] has a much larger selectivity than the benchmark solvent sulfolane. - Abstract: The distillation of close boiling mixtures may be improved by adding a proper affinity solvent, and thereby creating an extractive distillation process. An example of a close boiling mixture that may be separated by extractive distillation is the mixture ethylbenzene/styrene. The ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) is a promising solvent to separate ethylbenzene and styrene by extractive distillation. In this study, (vapour + liquid) equilibrium data have been measured for the binary system (styrene + [EMIM][SCN]) over the pressure range of (3 to 20) kPa and binary and ternary (liquid + liquid) equilibrium data of the system (ethylbenzene + styrene + [EMIM][SCN]) at temperatures (313.2, 333.2 and 353.2) K. Due to the low solubility of ethylbenzene in [EMIM][SCN], it was not possible to measure accurately VLE data of the binary system (ethylbenzene + [EMIM][SCN]) and of the ternary system (ethylbenzene + styrene + [EMIM][SCN]) using the ebulliometer. Because previous work showed that the LLE selectivity is a good measure for the selectivity in VLE, we determined the selectivity with LLE. The selectivity of [EMIM][SCN] to styrene in LLE measurements ranges from 2.1 at high styrene raffinate purity to 2.6 at high ethylbenzene raffinate purity. The NRTL model can properly describe the experimental results. The rRMSD in temperature, pressure and mole fraction for the binary VLE data are respectively (0.1, 0.12 and 0.13)%. The rRMSD is only 0.7% in mole fraction for the LLE data.

  20. Preparation of Sufonated Poly (ethylene-co-tetrafluoroethylene-graft-styrene Based Polymer Electrolyte Membranes for Fuel Cell by using Gamma Irradiation Technique

    Directory of Open Access Journals (Sweden)

    A. Suliwarno

    2012-04-01

    Full Text Available Poly (ethylene-co-tetrafluoroethylene-graft-styrene-sulfonate was successfully prepared by irradiation grafting of a styrene monomer into ethylenetetrafluoro-ethylene (ETFE films and followed by sulfonation of the graft chains. Five film sheets of ETFE which having a size of 3 cm  8 cm, thickness of 25 µm were packed in vacuum using a Y type tube filled with argon gas. The samples were irradiated using γ-rays with a dose of 15 kGy at 15 kGy/h. The iradiated samples were grafted by using styrene monomer at 60o C for 1, 3, 5, 7 and 9 h, respectively. The grafted samples (ETFE-g-St were washed with xylene to remove homopolymer of polystyrene, and then its degree of grafting (DG was determined. Sulfonation was carried out by using 0.2 M chlorosulfonic acid in dichloroethane solution at a water bath of 60oC for 6 h. Sulfonated samples (ETFE-g-St-SO3H were washed with water to neutralize its acidity, and dried in a vacuum drier at 40oC for 15 h. The dried sample was weighed as sulfonated sample in order to determine the degree of sulfonation (%DS. Membrane properties of EFTE-g-St-SO3H sample such as ion exchange capacity (IEC, proton conductivity in cross direction (σ1, and in-plane direction (σ11 were determined by using a HIOKI-3522 LCR HI tester. Durability test of samples were conducted in hot water and 3% H2O2 respectively.. The proton conductivity measurement and durability of the membrane were compared to Nafion 112® as standard. The experimental results showed that the degree of grafting was increased with time of reaction for copolymerization, while %DS gave excellent results with an average of 92.7%. The IEC value was more affected by the %DG as compared to that of %DS effect. The average of σl value of the sample was 0.055 S/cm, compared to σl of Nafion112® that was 0.066 S/cm. The average of ll of the sample was 0.18 S/cm, while the ll of Nafion 112® was = 0.36 S/cm. The sample of SA004 with 53.49% DG was more stable than

  1. Ignition studies of n-heptane/iso-octane/toluene blends

    KAUST Repository

    Javed, Tamour

    2016-07-09

    Ignition delay times of four ternary blends of n-heptane/iso-octane/toluene, referred to as Toluene Primary Reference Fuels (TPRFs), have been measured in a high-pressure shock tube and in a rapid compression machine. The TPRFs were formulated to match the research octane number (RON) and motor octane number (MON) of two high-octane gasolines and two prospective low-octane naphtha fuels. The experiments were carried out over a wide range of temperatures (650–1250 K), at pressures of 10, 20 and 40 bar, and at equivalence ratios of 0.5 and 1.0. It was observed that the ignition delay times of these TPRFs exhibit negligible octane dependence at high temperatures (T > 1000 K), weak octane dependence at low temperatures (T < 700 K), and strong octane dependence in the negative temperature coefficient (NTC) regime. A detailed chemical kinetic model was used to simulate and interpret the measured data. It was shown that the kinetic model requires general improvements to better predict low-temperature conditions and particularly requires improvements for high sensitivity (high toluene concentration) TPRF blends. These datasets will serve as important benchmark for future gasoline surrogate mechanism development and validation. © 2016 The Combustion Institute

  2. Toluene nitration in irradiated nitric acid and nitrite solutions

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Gracy, E-mail: gracy.elias@inl.go [Idaho National Laboratory, Chemical and Radiation Measurement Department, P.O. Box 1625, Idaho Falls, ID 83415-2213 (United States); Mincher, Bruce J. [Idaho National Laboratory, Aqueous Separations and Radiochemistry Department, P.O. Box 1625, Idaho Falls, ID 83415-6180 (United States); Mezyk, Stephen P. [California State University-Long Beach, Department of Chemistry and Biochemistry, 1250 Bellflower Boulevard, Long Beach, CA 90840-3903 (United States); Muller, Jim [University of Utah, Department of Chemistry, Salt Lake City, UT 84112-0850 (United States); Martin, Leigh R. [Idaho National Laboratory, Aqueous Separations and Radiochemistry Department, P.O. Box 1625, Idaho Falls, ID 83415-6180 (United States)

    2011-04-15

    The kinetics, mechanisms, and stable products produced for the nitration of aryl alkyl mild ortho-para director toluene in irradiated nitric acid and neutral nitrite solutions were investigated using {gamma} and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection, GC-MS and LC-MS, were used to assess the stable reaction products. Free-radical based nitration reaction products were found in irradiated acidic and neutral media. In 6.0 M HNO{sub 3}, ring substitution, side chain substitution, and oxidation, produced different nitrated toluene products. For ring substitution, nitrogen oxide radicals were added mainly to cyclohexadienyl radicals, whereas for side chain substitution, these radicals were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite solutions, radiolytically-induced ring nitration products approached a statistically random distribution, suggesting a direct free-radical reaction involving addition of the {sup {center_dot}N}O{sub 2} radical.

  3. Toluene nitration in irradiated nitric acid and nitrite solutions

    Science.gov (United States)

    Elias, Gracy; Mincher, Bruce J.; Mezyk, Stephen P.; Muller, Jim; Martin, Leigh R.

    2011-04-01

    The kinetics, mechanisms, and stable products produced for the nitration of aryl alkyl mild ortho-para director toluene in irradiated nitric acid and neutral nitrite solutions were investigated using γ and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection, GC-MS and LC-MS, were used to assess the stable reaction products. Free-radical based nitration reaction products were found in irradiated acidic and neutral media. In 6.0 M HNO3, ring substitution, side chain substitution, and oxidation, produced different nitrated toluene products. For ring substitution, nitrogen oxide radicals were added mainly to cyclohexadienyl radicals, whereas for side chain substitution, these radicals were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite solutions, radiolytically-induced ring nitration products approached a statistically random distribution, suggesting a direct free-radical reaction involving addition of the rad NO2 radical.

  4. Toluene nitration in irradiated nitric acid and nitrite solution

    Energy Technology Data Exchange (ETDEWEB)

    Gracy Elias; Bruce J. Mincher; Stephen P. Mezyk; Jim Muller; Leigh R. Martin

    2011-04-01

    The kinetics, mechanisms, and stable products produced for the aryl alkyl mild ortho-para director - toluene, in irradiated nitric acid and neutral nitrite solutions were investigated using ?, and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection was primarily used to assess the stable reaction products. GC-MS and LC-MS were used to confirm the results from HPLC. Free-radical nitration reaction products were found in irradiated acidic and neutral media. In acidic medium, the ring substitution and side chain substitution and oxidation produced different nitro products. In ring substitution, nitrogen oxide radicals were added mainly to hydroxyl radical-produced cyclohexadienyl radical, and in side chain substitution they were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite toluene solution, radiolytic ring nitration products approached a statistically random distribution, suggesting a free-radical reaction involving addition of the •NO2 radical.

  5. Toluene nitration in irradiated nitric acid and nitrite solutions

    International Nuclear Information System (INIS)

    Elias, Gracy; Mincher, Bruce J.; Mezyk, Stephen P.; Muller, Jim; Martin, Leigh R.

    2011-01-01

    The kinetics, mechanisms, and stable products produced for the nitration of aryl alkyl mild ortho-para director toluene in irradiated nitric acid and neutral nitrite solutions were investigated using γ and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection, GC-MS and LC-MS, were used to assess the stable reaction products. Free-radical based nitration reaction products were found in irradiated acidic and neutral media. In 6.0 M HNO 3 , ring substitution, side chain substitution, and oxidation, produced different nitrated toluene products. For ring substitution, nitrogen oxide radicals were added mainly to cyclohexadienyl radicals, whereas for side chain substitution, these radicals were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite solutions, radiolytically-induced ring nitration products approached a statistically random distribution, suggesting a direct free-radical reaction involving addition of the · NO 2 radical.

  6. Visual evoked potentials in rotogravure printers exposed to toluene.

    Science.gov (United States)

    Urban, P; Lukás, E

    1990-01-01

    Visual evoked potentials (VEPs) from stimulation by checkerboard pattern reversal were examined in 54 rotogravure printers exposed to toluene (all men, aged 22-64 years, duration of exposure 1-41 years). A control group consisted of 46 subjects (23 men and 23 women; aged 22-54 years). Compared with controls the exposed group showed more frequent responses with reduced reproducibility or absence of some waves, or both; the mean P1 wave latency was prolonged and mean amplitudes N1P1 and P1N2 were reduced. The VEPs were abnormal in 24% of workers. The frequency of abnormal VEPs correlated positively with the duration of exposure to toluene and also with the degree of alcohol drinking. No association was found between measurements of VEP and electroencephalogram (EEG) or electromyogram (EMG) examinations. A VEP measurement was made in 78% of the exposed workers two years after the first examination. No statistically significant difference between the two results was found. This suggests a marked stability of the observed VEP changes. These changes can be interpreted as a subclinical sign of dysfunction of the central nervous system (CNS) related to exposure to toluene and also to alcohol consumption. PMID:2271388

  7. Opioid Receptor Activity and Analgesic Potency of DPDPE Peptide Analogues Containing a Xylene Bridge.

    Science.gov (United States)

    Stefanucci, Azzurra; Novellino, Ettore; Mirzaie, Sako; Macedonio, Giorgia; Pieretti, Stefano; Minosi, Paola; Szűcs, Edina; Erdei, Anna I; Zádor, Ferenc; Benyhe, Sándor; Mollica, Adriano

    2017-04-13

    d-Pen 2 ,d-Pen 5 enkephalin (DPDPE) is one of the most selective synthetic peptide agonists targeting the δ-opioid receptor. Three cyclic analogues of DPDPE containing a xylene bridge in place of disulfide bond have been synthesized and fully characterized as opioid receptors agonists. The in vitro activity was investigated showing a good affinity of 7a - c for μ- and δ-receptors. In vivo biological assays revealed that 7b is the most potent analogue with the ability to maintain high level of analgesia from 15 to 60 min following intracerebroventricular (i.c.v.) administration, whereas DPDPE was slightly active until 45 min. Compound 7b induced long lasting analgesia also after subcutaneous administration, whereas DPDPE was inactive.

  8. Selective Production of Renewable para-Xylene by Tungsten Carbide Catalyzed Atom-Economic Cascade Reactions.

    Science.gov (United States)

    Dai, Tao; Li, Changzhi; Li, Lin; Zhao, Zongbao Kent; Zhang, Bo; Cong, Yu; Wang, Aiqin

    2018-02-12

    Tungsten carbide was employed as the catalyst in an atom-economic and renewable synthesis of para-xylene with excellent selectivity and yield from 4-methyl-3-cyclohexene-1-carbonylaldehyde (4-MCHCA). This intermediate is the product of the Diels-Alder reaction between the two readily available bio-based building blocks acrolein and isoprene. Our results suggest that 4-MCHCA undergoes a novel dehydroaromatization-hydrodeoxygenation cascade process by intramolecular hydrogen transfer that does not involve an external hydrogen source, and that the hydrodeoxygenation occurs through the direct dissociation of the C=O bond on the W 2 C surface. Notably, this process is readily applicable to the synthesis of various (multi)methylated arenes from bio-based building blocks, thus potentially providing a petroleum-independent solution to valuable aromatic compounds. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Fluorescence resonance energy transfer in AOT/4-chlorophenol/m-xylene organogels

    International Nuclear Information System (INIS)

    Dandapat, Manika; Mandal, Debabrata

    2015-01-01

    Fluorescence Resonance Energy Transfer (FRET) between donor coumarins (C102 and C153) and acceptor Rhodamine 6G were studied in AOT/4-chlorophenol/m-xylene organogels. The gel comprises a three-dimensional network of fiber bundles trapping the m-xylene solvent. Each fiber is an aggregate of several strands, and each strand consists of a central columnar stack of the phenols, surrounded by AOT headgroups. Our acceptor is ionic so that it was concentrated near the polar center of the strand, while the neutral donors were likely distributed over a wider region. With C153 as donor, clear evidence of FRET (time-constant~100 ps) was found, which indicated that the donor and acceptor may reside in neighboring strands within the same fiber. However, with C102 as donor, FRET probably occurred over an ultrashort, sub-picosecond time-scale suggesting that the donor and acceptor in this case resided in close vicinity. Thus, C102 tends to localize near the polar centre of the strands, compared to the more hydrophobic C153, which prefers to occupy the relatively non-polar peripheral regions of the strands and fibers. - Highlights: • FRET between coumarin donors and Rhodamine 6G acceptor studied in AOT organogels. • With Coumarin 153 donor, a ~100 ps FRET component detected in both donor and acceptor fluorescence. • With Coumarin 102 donor, FRET component too short to be detected with a time-resolution of ~70 ps. • The FRET rates reveal crucial differences in donor–acceptor distances for the two coumarin donors

  10. Conformational instability of the lowest triplet state of the benzene nucleus: II. p-Xylene, the influence of substituents

    NARCIS (Netherlands)

    van der Waals, J.H.; van Hemert, M.C.; Buma, W.J.

    1990-01-01

    A calculation of the potential-energy surface of the lowest triplet state of p-xylene as a function of the S8(,) distortion coordinate of the benzene skeleton has been made to learn more about the influence of substituents on the vibronically induced distortion of benzene in its metastable triplet

  11. High activity of iron containing metal-organic-framework in acylation of p-xylene with benzoyl chloride

    Czech Academy of Sciences Publication Activity Database

    Kurfiřtová, Lenka; Seo, Y.; K.; Hwang, Y. K.; Chang, J.; S.; Čejka, Jiří

    2012-01-01

    Roč. 179, č. 1 (2012), s. 85-90 ISSN 0920-5861 R&D Projects: GA ČR GA104/07/0383 Institutional research plan: CEZ:AV0Z40400503 Keywords : acylation * p-xylene * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.980, year: 2012

  12. 21 CFR 175.380 - Xylene-formaldehyde resins condensed with 4,4′-isopropylidenediphenol-epichlorohydrin epoxy resins.

    Science.gov (United States)

    2010-04-01

    ...-isopropylidenediphenol-epichlorohydrin epoxy resins. 175.380 Section 175.380 Food and Drugs FOOD AND DRUG ADMINISTRATION... Xylene-formaldehyde resins condensed with 4,4′-isopropylidenediphenol-epichlorohydrin epoxy resins. The...′-isopropylidenediphenol-epichlorohydrin epoxy resins, to which may have been added certain optional adjuvant substances...

  13. Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts

    KAUST Repository

    Alabi, Wahab

    2012-07-01

    A kinetic study of toluene alkylation with methanol was performed over pure HZSM-5, mordenite/ZSM-5 (hybrid of mordenite and HZSM-5), and ZM13 (composite mixture of HZSM-5 and MCM-41 at pH 13). Experimental runs were conducted using a batch fluidized bed reactor at temperatures of 300, 350 and 400 °C and reaction times of 3, 5, 7, 10, 13, 15 and 20. s. The rate of toluene methylation and toluene disproportionation were studied on the three catalysts (toluene alkylation is usually accompanied by toluene disproportionation on acid catalyst). Based on the results obtained, a simplified power law kinetic model consisting of three reactions was developed to estimate the activation energies of toluene methylation and disproportionation simultaneously. Coke formation on catalysts was accounted for using both reaction time and reactant conversion decay functions. All parameters were estimated based on quasi-steady state approximation. Estimated kinetic parameters were in good agreement with experimental results. The order of alkylation ability of the catalysts was found to be ZM13 > HZSM-5 > mordenite/ZSM-5, while the reverse is for toluene disproportionation (mordenite/ZSM-5 > HZSM-5 > ZM13). Thus, alkylation of toluene is most favorable on ZM13 due to combined effect of mesoporosity induced through its synthetic route and acid content. Toluene/MeOH molar ratio of 1:1 was most suitable for toluene alkylation reaction. © 2012 Elsevier B.V.

  14. Acute behavioural comparisons of toluene and ethanol in human subjects.

    Science.gov (United States)

    Echeverria, D; Fine, L; Langolf, G; Schork, T; Sampaio, C

    1991-11-01

    A comparison of toluene and ethanol (EtOH) induced changes in central nervous system (CNS) function and symptoms were evaluated in two studies, and when possible the effects of toluene were expressed in EtOH equivalent units. The toluene concentrations were 0, 75, and 150 ppm, bracketing the American Conference of Governmental Industrial Hygienists threshold limit value (ACGIH TLV) of 100 ppm. The socially relevant EtOH doses were 0.00, 0.33, and 0.66 g EtOH/kg body weight, equivalent to two and four 3.5% 12 ounce beers. Forty two paid college students were used in each study. In the first study, subjects were exposed to toluene and an odour masking agent menthol (0.078 ppm) for seven hours over three days. In the second study EtOH or a placebo was administered at 1530 across three days also in the presence of menthol. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory), perception (pattern recognition), psychomotor skill (simple reaction time, continuous performance, symbol-digit, hand-eye coordination, finger tapping, and critical tracking), manual dexterity (one hole), mood (profile on mood scales (POMS), fatigue (fatigue checklist), and verbal ability were evaluated at 0800, 1200, and 1600. Voluntary symptoms and observations of sleep were collected daily. A 3 x 3 latin square design evaluated solvent effects simultaneously controlling for learning and dose sequence. An analysis of variance and test for trend were performed on am-pm differences reflecting an eight hour workday and on pm scores for each solvent, in which subjects were their own control Intersubject variation in absorbance was monitored in breath. A 5 to 10% decrement was considered meaningful if consistent with a linear trend at p less than 0.05. At 150 ppm toluene, losses in performance were 6.0% for digit span, 12.1% for pattern recognition (latency), 5% for pattern memory (number correct), 6.5% for one hole, and 3% for critical tracking. The number of headaches

  15. Rapid microbial mineralization of toluene and 1,3-dimethylbenzene in the absence of molecular oxygen.

    Science.gov (United States)

    Zeyer, J; Kuhn, E P; Schwarzenbach, R P

    1986-10-01

    Up to 0.4 mM 1,3-dimethylbenzene (m-xylene) was rapidly mineralized in a laboratory aquifer column operated in the absence of molecular oxygen with nitrate as an electron acceptor. Under continuous flow conditions, the degradation rate constant (pseudo-first order) was >0.45 h. Based on a carbon mass balance with [ring-C]m-xylene and a calculation of the electron balance, m-xylene was shown to be quantitatively (80%) oxidized to CO(2) with a concomitant reduction of nitrate. The mineralization of m-xylene in the column also took place after reducing the redox potential, E', of the inflowing medium with sulfide to sediments, sludge digestors, and groundwater infiltration zones from landfills and polluted rivers are not necessarily persistent but may be mineralized in the absence of molecular oxygen.

  16. Metabolism of styrene-7,8-oxide in human liver in vitro: interindividual variation and stereochemistry

    NARCIS (Netherlands)

    Wenker, M. A.; Kezić, S.; Monster, A. C.; de Wolff, F. A.

    2000-01-01

    Styrene is an industrial solvent which is mainly oxidized by cytochrome P450 to an electrophilic, chiral epoxide metabolite: styrene-7,8-oxide (SO). SO has cytotoxic and genotoxic properties; the (R)-enantiomer is more mutagenic to Salmonella typhimurium TA 100 in the Ames test than the

  17. Thermotropic properties of phosphatidylcholine nanodiscs bounded by styrene-maleic acid copolymers

    NARCIS (Netherlands)

    Dominguez Pardo, J.J.; Dörr, J.M.; Renne, M.F.; Ould-Braham, T; Koorengevel, M.C.; van Steenbergen, Mies; Killian, J.A.

    2017-01-01

    Styrene-maleic acid copolymers (SMA) have been gaining interest in the field of membrane research due to their ability to solubilize membranes into nanodics. The SMA molecules act as an amphipathic belt that surrounds the nanodiscs, whereby the hydrophobic styrene moieties can insert in between the

  18. EVALUATION OF STYRENE EMISSIONS FROM A SHOWER STALL/BATHTUB MANUFACTURING FACILITY

    Science.gov (United States)

    The report gives results of emissions measurements carried out at a representative facility (Eljer Plumbingware in Wilson, NC) that manufactures polyester-resin-reinforced shower stalls and bathtubs by spraying styrene-based resins onto molds in vented, open, spray booths. Styren...

  19. Coke formation in the oxidative dehydrogenation of ethylbenzene to styrene by TEOM

    NARCIS (Netherlands)

    Nederlof, C.; Vijfhuizen, P.; Zarubina, V.; Melian-Cabrera, I.; Kapteijn, F.; Makkee, M.

    2014-01-01

    A packed bed microbalance reactor setup (TEOM-GC) is used to investigate the formation of coke as a function of time-on-stream on gamma-Al2O3 and 3P/SiO2 catalyst samples under different conditions for the ODH reaction of ethylbenzene to styrene. All samples show a linear correlation of the styrene

  20. POTENTIAL FOR REDUCING INDOOR STYRENE EXPOSURE FROM COPIED PAPER THROUGH USE OF LOW-EMITTING TONERS

    Science.gov (United States)

    Tests were conducted, using 53-L dynamic chambers, to determine airborne styrene emission rates over time from freshly copied paper. Copies were produced on a single photocopier, using two toners manufactured for this copier but having different styrene contents. The resulting em...

  1. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, condensated... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

  2. Exploiting Framework Flexibility of a Metal-Organic Framework for Selective Adsorption of Styrene over Ethylbenzene

    NARCIS (Netherlands)

    Mukherjee, S.; Joarder, B.; Desai, A.V.; Manna, B.; Krishna, R.; Ghosh, S.K.

    2015-01-01

    The separation of styrene and ethylbenzene mixtures is industrially important and is currently performed in highly energy-intensive vacuum distillation columns. The primary objective of our investigation is to offer an energy-efficient alternative for selective adsorption of styrene by a flexible

  3. Utilizing the phenol byproducts of coke production: 3. Phenols as coinhibitors of thermopolymerization during styrene production

    Energy Technology Data Exchange (ETDEWEB)

    I.I. Batura; A.F. Gogotov; V.I. Cherepanov; O.I. Baranov; A.A. Levchuk; M.V. Parilova [Irkutsk State Technical University, Irkutsk (Russian Federation)

    2009-01-15

    A new oligomerization procedure for phenol byproducts from coke production is experimentally studied. This method, oxidative combination, is intended to produce an effective coinhibitor of styrene thermopolymerization. When combined with a Mannich base, the new oligomer exhibits excellent inhibiting properties in the heat treatment of styrene and matches the effectiveness of imported inhibitors based on nitroxyl radicals. 15 refs., 1 tab.

  4. Atom transfer radical polymerization of styrene under pulsed microwave irradiation

    International Nuclear Information System (INIS)

    Cheng Zhenping; Zhu Xiulin; Zhou Nianchen; Zhu Jian; Zhang Zhengbiao

    2005-01-01

    A homogeneous solution atom transfer radical polymerization (ATRP) and reverse atom transfer radical polymerization (RATRP) of styrene (St) in N,N-dimethylformamide (DMF) were successfully carried out under pulsed microwave irradiation (PMI), using 1-bromo-1-phenylethane (1-PEBr)/CuCl/N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) as an initiating system at 85 deg. C and 2,2'-azo-bis-isobutyrontrile (AIBN)/CuCl 2 /PMDETA as an initiating system at 95 deg. C, respectively. The polymerization rates under PMI were greatly increased in comparison with those under identical conventional heating (CH)

  5. The radiolysis of styrene methyl acrylate copolymers: An ESR study

    International Nuclear Information System (INIS)

    Kellman, R.; Hill, D.T.J.; O'Donnell, J.H.; Pomery, P.J.

    1990-01-01

    The authors have examined the degradation of poly(styrene-co-methyl acrylate) under high-energy radiation, and wish to report results of an ESR study on the formation and fate of radical species produced during radiolysis. Radical yields, G[R], for STY-co-MA polymers have been determined at both 77K and 300K. ESR spectral analysis has allowed structural determination and an examination of the behavior of radicals species produced on radiolysis. Aspects of the free radical chemistry responsible for polymer degradation are discussed

  6. 40 CFR 63.500 - Back-end process provisions-carbon disulfide limitations for styrene butadiene rubber by emulsion...

    Science.gov (United States)

    2010-07-01

    ... disulfide limitations for styrene butadiene rubber by emulsion processes. 63.500 Section 63.500 Protection... limitations for styrene butadiene rubber by emulsion processes. (a) Owners or operators of sources subject to this subpart producing styrene butadiene rubber using an emulsion process shall operate the process...

  7. 40 CFR 721.7020 - Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic name).

    Science.gov (United States)

    2010-07-01

    ...), polymers with styrene and mixed terpenes (generic name). 721.7020 Section 721.7020 Protection of...), C(3-6), polymers with styrene and mixed terpenes (generic name). (a) Chemical substance and...), polymers with styrene and mixed terpenes (PMN P-89-676) is subject to reporting under this section for the...

  8. Synthesis and Characterization of Styrene- Ethylene-Propylene-Styrene (SEPS) Grafted with Maleic Anhydride (MAH) for Use as Coupling Agent in Wood Polymer Composite

    OpenAIRE

    M. Acevedo-Morantes; A. Tapia; J. Correa; A. Realpe-Jimenez; C. Gartner

    2015-01-01

    Styrene-Ethylene-Propylene-Styrene (SEPS) block copolymer was grafted with maleic anhydride (MAH) by reactive extrusion (SEPS-g-MAH) using an organic peroxide as initiator in the grafting. SEPS-g-MAH was synthesized for use as coupling agent in wood polymer composite (WPC). Identification of this compatibilizer was made using Fourier transform infrared spectroscopy (FTIR) and the grafting degree was determinate with titration. The characteristic peaks in FTIR analysis indicated the presence o...

  9. Enhanced linear and nonlinear optical properties of thermally stable ZnO/poly(styrene)–poly(methyl methacrylate) nanocomposite films

    International Nuclear Information System (INIS)

    Jeeju, P.P.; Jayalekshmi, S.; Chandrasekharan, K.; Sudheesh, P.

    2013-01-01

    Highly transparent and thermally stable zinc oxide (ZnO)/poly(styrene)–poly(methyl methacrylate) (PS–PMMA) nanocomposite films have been deposited on glass substrates, from the ZnO incorporated (PS–PMMA) solutions in toluene, using spin coating technique. A chemical route at room temperature is used to synthesize the ZnO nanoparticles. Transmission electron microscope and high-resolution transmission electron microscope images show that the ZnO nanoparticles are of size around 10 nm. The composite films have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy, Ultraviolet–visible–Near Infrared (UV–vis–NIR) spectroscopy, Thermo-gravimetric analysis, photoluminescence (PL) spectroscopy and Z-scan technique. From the UV–vis–NIR spectra it is observed that the ZnO/PS–PMMA nanocomposite films with 10 wt.% ZnO content exhibit excellent shielding property in the UV region and, high transparency in the visible region. The PL spectrum of the composite films is different from that of ZnO and PS–PMMA blend and exhibits an excitonic emission peak at ∼ 375 nm. The optical absorptive nonlinearity in the nanocomposite films is investigated using open aperture Z-scan technique. The results indicate optical limiting type nonlinearity in the films due to two photon absorption. A transmittance minimum of around 0.25 has been observed in the ZnO/PS–PMMA nanocomposite films which is much lower compared to that in ZnO/PMMA and ZnO/PS nanocomposite films. The ZnO/PS–PMMA nanocomposite films also show a self-defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. These nanocomposite films extend ample scope of applications as excellent optical limiters and efficient UV protectors. - Highlights: ► Transparent, ZnO/poly(styrene)–poly(methyl methacrylate) composite films are prepared. ► The nanocomposite films with 10 wt.% ZnO content exhibit good UV-shielding property.

  10. Enhanced linear and nonlinear optical properties of thermally stable ZnO/poly(styrene)–poly(methyl methacrylate) nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Jeeju, P.P., E-mail: jeejupp@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi 682 022, Kerala (India); Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi 682 022, Kerala (India); Chandrasekharan, K.; Sudheesh, P. [Department of Physics, National Institute of Technology, Calicut, Kerala (India)

    2013-03-01

    Highly transparent and thermally stable zinc oxide (ZnO)/poly(styrene)–poly(methyl methacrylate) (PS–PMMA) nanocomposite films have been deposited on glass substrates, from the ZnO incorporated (PS–PMMA) solutions in toluene, using spin coating technique. A chemical route at room temperature is used to synthesize the ZnO nanoparticles. Transmission electron microscope and high-resolution transmission electron microscope images show that the ZnO nanoparticles are of size around 10 nm. The composite films have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy, Ultraviolet–visible–Near Infrared (UV–vis–NIR) spectroscopy, Thermo-gravimetric analysis, photoluminescence (PL) spectroscopy and Z-scan technique. From the UV–vis–NIR spectra it is observed that the ZnO/PS–PMMA nanocomposite films with 10 wt.% ZnO content exhibit excellent shielding property in the UV region and, high transparency in the visible region. The PL spectrum of the composite films is different from that of ZnO and PS–PMMA blend and exhibits an excitonic emission peak at ∼ 375 nm. The optical absorptive nonlinearity in the nanocomposite films is investigated using open aperture Z-scan technique. The results indicate optical limiting type nonlinearity in the films due to two photon absorption. A transmittance minimum of around 0.25 has been observed in the ZnO/PS–PMMA nanocomposite films which is much lower compared to that in ZnO/PMMA and ZnO/PS nanocomposite films. The ZnO/PS–PMMA nanocomposite films also show a self-defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. These nanocomposite films extend ample scope of applications as excellent optical limiters and efficient UV protectors. - Highlights: ► Transparent, ZnO/poly(styrene)–poly(methyl methacrylate) composite films are prepared. ► The nanocomposite films with 10 wt.% ZnO content exhibit good UV-shielding property.

  11. Investigation of free-radical processes in low temperature radiolysis of copolymers of ethylene with styrene

    International Nuclear Information System (INIS)

    Mal'tseva, A.P.; Golikov, V.P.; Leshchenko, S.S.; Karpov, V.L.; Muromtsev, V.I.

    1977-01-01

    Free radical processes during γ-radiolysis of statistical ethylene-styrene copolimers (ESC) have been investigated. The presence of styrene links in the ESC has been shown to reduce both radical yields and their reaction ability as compared with low density polyethylene irradiated under the same conditions. The character of radical processes in ESC sighificantly depends both on styrene concentration in them and on the dose absorbed. The most pronounced decrease in radical yield is found in the copolymer having 5 mol % styrene. This effect seems to be caused by the accumulation in the irradiated copolymer of products which are capable of more effective dissipation of absorbed energy than only styrene links alone

  12. Plasma modification of polypropylene surfaces and its alloying with styrene in situ

    International Nuclear Information System (INIS)

    Ma Guiqiu; Liu Ben; Li Chen; Huang Dinghai; Sheng Jing

    2012-01-01

    The treatment of polypropylene surfaces has been studied by dielectric barrier discharges plasma of Ar. The structure and morphology of polypropylene surfaces of Ar plasma modification are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometers and scanning electron microscope. The modified by plasma treatment of iPP (isotactic polypropylene) surface properties have been examined in a determination of free radicals. The modified active surfaces of polypropylene can induce grafting copolymerization of styrene onto polypropylene. The structure of grafting copolymer is characterized and the grafting percent of styrene onto polypropylene is calculated. The homopolymer of styrene can be formed under grafting copolymerization of styrene onto polypropylene, which follows that the alloying of polypropylene with styrene is achieved in situ.

  13. Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

    International Nuclear Information System (INIS)

    Li Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

    2005-01-01

    Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance

  14. Plasma modification of polypropylene surfaces and its alloying with styrene in situ

    Energy Technology Data Exchange (ETDEWEB)

    Ma Guiqiu, E-mail: magq@tju.edu.cn [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China); Liu Ben; Li Chen; Huang Dinghai; Sheng Jing [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China)

    2012-01-15

    The treatment of polypropylene surfaces has been studied by dielectric barrier discharges plasma of Ar. The structure and morphology of polypropylene surfaces of Ar plasma modification are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometers and scanning electron microscope. The modified by plasma treatment of iPP (isotactic polypropylene) surface properties have been examined in a determination of free radicals. The modified active surfaces of polypropylene can induce grafting copolymerization of styrene onto polypropylene. The structure of grafting copolymer is characterized and the grafting percent of styrene onto polypropylene is calculated. The homopolymer of styrene can be formed under grafting copolymerization of styrene onto polypropylene, which follows that the alloying of polypropylene with styrene is achieved in situ.

  15. [Mechanism and performance of styrene oxidation by O3/H2O2].

    Science.gov (United States)

    He, Jue-Cong; Huang, Qian-Ru; Ye, Qi-Hong; Luo, Yu-Wei; Zhang, Zai-Li; Fan, Qing-Juan; Wei, Zai-Shan

    2013-10-01

    It can produce a large number of free radicals in O3/H2O2, system, ozone and free radical coupling oxidation can improve the styrene removal efficiency. Styrene oxidation by O3/H2O2 was investigated. Ozone dosage, residence time, H2o2 volume fraction, spray density and molar ratio of O3/C8H8 on styrene removal were evaluated. The experimental results showed that styrene removal efficiency achieved 85.7%. The optimal residence time, H2O2, volume fraction, spray density and O3/C8H8 molar ratio were 20. 6 s, 10% , 1.72 m3.(m2.h)-1 and 0.46, respectively. The gas-phase degradation intermediate products were benzaldehyde(C6H5CHO) and benzoic acid (C6H5 COOH) , which were identified by means of gas chromatography-mass spectrometry(GC-MS). The degradation mechanism of styrene is presented.

  16. The influence of the association patterns of phosphorus–substrates and xylene–substrates on the degradation of xylenes in an alluvial aquifer

    Directory of Open Access Journals (Sweden)

    SANJA MRKIC

    2005-12-01

    Full Text Available The association patterns of xylene and of total phosphorus with sediment constituents in an alluvial aquifer consisting of clays and sands which had been contaminated by a spill of technical grade xylene were investigated with the aim of assessing the dependence of in situ xylene degradation on the P-availability. The investigated alluvial sediments of the Maki{ Plain (Sava river alluvion, Quaternary age, Serbia and Montenegro are relatively poor in P. The most reliable associations were proposed by analyzing the quality of the correlations of xylene- and of P-contents with 32 sediment characteristics. The association patterns depend on the mineralogical and granulometrical composition of sediments, the structural characteristics of the organicmatter (N/C-ratio and the redox-conditions. Differing association patterns in the clays and the sand had been developed, and these characteristics influence the intrinsic xylene degradation. The main proof for the occurrence of xylene degradation is the percentul share of bacteria which oxidize xylene as a single carbon-source.

  17. Induction of resistance to X-rays in E. coli by toluene

    International Nuclear Information System (INIS)

    Gillies, N.E.; Ratnajothi, N.H.

    1980-01-01

    Incubation of unirradiated bacteria with 10 M toluene in buffer for 30 min at 22 0 C did not affect their viability. When E. Coli K12AB1157 were incubated in buffer/toluene (10 M) for 30 min and then X-irradiated under either aerobic or anaerobic conditions in the presence of toluene the derived curves contained large shoulders; the Dsub(q) values were calculated to be 271 Gy and 921 Gy for bacteria irradiated under oxic and anoxic conditions respectively. The final exponential slopes for both curves were less steep than those for the strictly exponential curves obtained for X-irradiated bacteria which had neither been pre-incubated with toluene nor X-irradiated in the presence of toluene. When bacteria were exposed to toluene during the time of X-irradiation only, exponential survival curves were observed with slopes approximately the same as the terminal slopes of the curves for the bacteria pretreated and irradiated in the presence of toluene. When the bacteria were exposed initially to X-rays and then incubated with toluene, the survival curves were identical to those obtained for bacteria untreated with toluene. Survival after U.V. irradiation was the same whether or not the bacteria were treated with toluene before exposure to U.V. The modification of radioresistance by toluene appeared to be independent of the presence of oxygen at the time of irradiation. It is suggested that toluene does not effect the primary fixation of lesions, but may influence their subsequent removal. (U.K.)

  18. Physical properties of (propyl propanoate + hexane + toluene) at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Freire, S. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain)]. E-mail: sfreire@udc.es; Segade, L. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain); Cabeza, O. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain); Jimenez, E. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain)

    2007-04-15

    The aim of this paper is to report experimental densities, excess molar enthalpies and refractive indexes of the ternary system (propyl propanoate + hexane + toluene) and of the corresponding binary mixtures (propyl propanoate + toluene) and (hexane + toluene) at the temperature 298.15 K and atmospheric pressure, over the whole composition range. Also, the excess molar volumes and the changes in the refractive index on mixing have been calculated from the measured data for all mixtures.

  19. Toluene and benzyl decomposition mechanisms: elementary reactions and kinetic simulations.

    Science.gov (United States)

    Derudi, Marco; Polino, Daniela; Cavallotti, Carlo

    2011-12-28

    The high temperature decomposition kinetics of toluene and benzyl were investigated by combining a kinetic analysis with the ab initio/master equation study of new reaction channels. It was found that similarly to toluene, which decomposes to benzyl and phenyl losing atomic hydrogen and methyl, also benzyl decomposition proceeds through two channels with similar products. The first leads to the formation of fulvenallene and hydrogen and has already been investigated in detail in recent publications. In this work it is proposed that benzyl can decompose also through a second decomposition channel to form benzyne and methyl. The channel specific kinetic constants of benzyl decomposition were determined by integrating the RRKM/master equation over the C(7)H(7) potential energy surface. The energies of wells and saddle points were determined at the CCSD(T) level on B3LYP/6-31+G(d,p) structures. A kinetic mechanism was then formulated, which comprises the benzyl and toluene decomposition reactions together with a recently proposed fulvenallene decomposition mechanism, the decomposition kinetics of the fulvenallenyl radical, and some reactions describing the secondary chemistry originated by the decomposition products. The kinetic mechanism so obtained was used to simulate the production of H atoms measured in a wide pressure and temperature range using different experimental setups. The calculated and experimental data are in good agreement. Kinetic constants of the new reaction channels here examined are reported as a function of temperature at different pressures. The mechanism here proposed is not compatible with the assumption often used in literature kinetic mechanisms that benzyl decomposition can be effectively described through a lumped reaction whose products are the cyclopentadienyl radical and acetylene.

  20. Sulfonated Poly(styrene) Chains Grafted on Magnetic Nanoparticles

    Science.gov (United States)

    Jiao, Yang; Yevelev, Anton; Parra, Javier; Akcora, Pinar; Stevens Institute of Technology Team

    2014-03-01

    Iron oxide nanoparticles functionalized with poly(styrene) (PS) chains at various grafting densities and loadings present stable and ordered nanostructures for tuning the mechanical and conductive properties in polymer composites. Strings, spherical and anisotropic clusters and well-dispersed particles are achieved with PS-grafted Fe3O4 nanoparticles in PS matrices upon varying the system parameters. In this work, we report the effect of sulfonic group locations on the aggregation state of polymer-grafted nanoparticles. Structures formed by the random and diblock copolymers of PS-poly(styrene sulfonate) (PSS) grafted particles will be discussed with small-angle x-ray scattering (SAXS) measurements in solution and melts. The conformational changes in PS-grafted chains and ion-containing grafts will be also presented in small-angle neutron-scattering (SANS) results to understand the role of polymer on the assembly of particles at the low grafting density. We acknowledge support by NSF-CAREER-DMR (#1048865).

  1. Tricarbonylbis(tricyclohexylphosphine-κPruthenium(0 toluene solvate

    Directory of Open Access Journals (Sweden)

    Andreas Nader

    2008-11-01

    Full Text Available The title compound, [Ru(C18H33P2(CO3]·C7H8, shows a distorted trigonal-bipyramdial coordination around the central Ru atom, with the two phosphine ligands occupying the axial positions. Two toluene molecules per asymmetric unit with site-occupation factors of 0.5 are observed. One of them forces two of the CO ligands to enclose a wider C—Ru—C bond angle [127.5 (3°] than in the solvent-free crystal structure of [Ru(PCy32(CO3] (Cy is cyclohexyl.

  2. Characterization of toluene metabolism by methanotroph and its effect on methane oxidation.

    Science.gov (United States)

    He, Ruo; Su, Yao; Ma, Ruo-Chan; Zhuang, Shulin

    2018-04-03

    Methanotrophs not only oxidize CH 4 , but also can oxidize a relatively broad range of other substrates, including trichloroethylene, alkanes, alkenes, and aromatic compounds. In this study, Methylosinus sporium was used as a model organism to characterize toluene metabolism by methanotrophs. Reverse transcription quantitative PCR analysis showed that toluene enhanced the mmoX expression of M. sporium. When the toluene concentration was below 2000 mg m -3 , the kinetics of toluene metabolism by M. sporium conformed to the Michaelis-Menten equation (V max  = 0.238 g g dry weight -1  h -1 , K m  = 545.2 mg m -3 ). The use of a solid-phase extraction technique followed by a gas chromatography-mass spectrometry analysis and molecular docking calculation showed that toluene was likely to primarily bind the di-iron center structural region of soluble methane monooxygenase (sMMO) hydroxylase and then be oxidized to o-cresol. Although M. sporium oxidized toluene, it did not incorporate toluene into its biomass. The coexistence of toluene and CH 4 could influence CH 4 oxidation, the growth of methanotrophs, and the distribution of CH 4 -derived carbon, which were related to the ratio of the toluene concentration to biomass. These results would be helpful to understand the metabolism of CH 4 and non-methane volatile organic compounds in the environment.

  3. Ação promotora do berílio em catalisadores da síntese do estireno Promotor action of beryllium in catalysts for styrene production

    Directory of Open Access Journals (Sweden)

    Mário Nilo Mendes Barbosa

    1997-10-01

    Full Text Available The catalytic dehydrogenation of ethylbenzene in presence of steam is the main commercial route to produce styrene. The industrial catalysts are potassium- and chromia-doped hematite which show low surface areas leading to bad performance and short life. In order to develop catalysts with high areas, the effect of beryllium on the textural properties and on the catalytic performance of this iron oxide was studied. The influence of the amount of the dopant, the starting material and the calcination temperature were also studied. In sample preparations, iron and beryllium salts (nitrate or sulfate were hydrolyzed with ammonia and then calcinated. The experiments followed a factorial design with two variables in two levels (Fe/Be= 3 and 7; calcination temperature= 500 and 700ºC. Solids without any dopant were also prepared. Samples were characterized by elemental analysis, infrared spectroscopy, surface area and porosity measurements, X-ray diffraction, DSC and TG. The catalysts were tested in a microreactor at 524ºC and 1 atm, by using a mole ratio of steam/ ethylbenzene=10. The selectivity was measured by monitoring styrene, benzene and toluene formation. It was found that the effect of beryllium on the characteristics of hematite and on its catalytic performance depends on the starting material and on the amount of dopant. Surface areas increased due to the dopant as well as the nature of the precursor; samples produced by beryllium sulfate showed higher areas. Beryllium-doped solids showed a higher catalytic activity when compared to pure hematite, but no significant influence of the anion of starting material was noted. It can be concluded that beryllium acts as both textural and structural promoter. Samples with Fe/Be= 3, heated at 500ºC, lead to the highest conversion and were the most selective. However, catalysts prepared from beryllium sulfate are the most promising to ethylbenzene dehydrogenation due to their high surface area which

  4. Effect of Material Composition on Cohesion Characteristics of Styrene-Butadiene-Styrene-Modified Asphalt Using Surface Free Energy

    Directory of Open Access Journals (Sweden)

    Xing-jun Zhang

    2017-01-01

    Full Text Available Styrene-butadiene-styrene- (SBS- modified asphalts were prepared by mixing different base asphalts, SBS modifier, extracting oil, and stabilizing agents. The contact angles between SBS-modified asphalt and distilled water, glycerol, and formamide were detected by the sessile drop method. Based on the surface energy theory, the surface free energy and cohesive power of SBS-modified asphalt were calculated. The influence of the raw materials composition, such as the virgin asphalt and SBS modifier types as well as the extracting oil and stabilizing agent contents, on the cohesive characteristics of SBS-modified asphalt was discussed. The results showed that virgin asphalt was compatible with SBS modifiers to improve cohesiveness. The cohesive power of branched SBS-modified asphalt was larger than that of linear SBS-modified asphalt. The cohesion of SBS-modified asphalt was improved as the SBS modifier and stabilizer contents increased but was reduced for excessive extraction oil contents. The cohesive characteristics of the SBS-modified asphalt were improved by the formation of stable three-dimensional network structures by cross-linking, winding, and grafting among different raw materials.

  5. Dodecagonal Quasicrystalline Morphology in a Poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) Tetrablock Terpolymer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingwen; Bates, Frank S. (UMM)

    2012-10-26

    A dodecagonal quasicrystalline (QC) morphology is identified in a poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) (SISO) tetrablock terpolymer based on evidence provided by transmission electron microscopy (TEM), small-angle X-ray scattering, and dynamic mechanical spectroscopy measurements. The QC state occurs at temperatures between those associated with simple hexagonal order (HEX) and the {sigma}-phase (P4{sub 2}/mnm), T{sub HEX} < T{sub QC} < T{sub {sigma}} < T{sub ODT}, where T{sub ODT} is the order-disorder transition temperature. All three morphologies are formed from spherical domains containing an O core surrounded by a shell of S that screens unfavorable segment-segment interactions with an I-rich matrix. TEM analysis reveals a QC morphology with 12-fold rotational symmetry but devoid of long-range translational order, along with locally coordinated structures consistent with dodecagonal quasicrystalline approximants. The SISO molecular architecture decouples control over the domain shape and interdomain interactions, leading to a multiplicity of packing symmetries.

  6. Nanostructured poly(styrene-b-butadiene-b-styrene) (SBS) membranes for the separation of nitrogen from natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Buonomenna, Maria Giovanna; Golemme, Giovanni [Department of Chemical Engineering and Materials, University of Calabria, and Consorzio INSTM, Rende (Italy); Tone, Caterina Maria; De Santo, Maria Penelope; Ciuchi, Federica [IPCF-CNR UOS Cosenza, c/o Physics Department, University of Calabria, Rende (Italy); Perrotta, Enrico [Department of Ecology, University of Calabria, Rende (Italy)

    2012-04-24

    The preparation and characterization of new, tailor-made polymeric membranes using poly(styrene-b-butadiene-b-styrene) (SBS) triblock copolymers for gas separation are reported. Structural differences in the copolymer membranes, obtained by manipulation of the self-assembly of the block copolymers in solution, are characterized using atomic force microscopy, transmission electron microscopy, and the transport properties of three gases (CO{sub 2}, N{sub 2}, and CH{sub 4}). The CH{sub 4}/N{sub 2} ideal selectivity of 7.2, the highest value ever reported for block copolymers, with CH{sub 4} permeability of 41 Barrer, is obtained with a membrane containing the higher amount of polybutadiene (79 wt%) and characterized by a hexagonal array of columnar polystyrene cylinders normal to the membrane surface. Membranes with such a high separation factor are able to ease the exploitation of natural gas with high N{sub 2} content. The CO{sub 2}/N{sub 2} ideal selectivity of 50, coupled with a CO{sub 2} permeability of 289 Barrer, makes SBS a good candidate for the preparation of membranes for the post-combustion capture of carbon dioxide. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Assessment of the peripheral, central, and autonomic nervous system function in styrene workers

    Energy Technology Data Exchange (ETDEWEB)

    Murata, K.; Araki, S.; Yokoyama, K. (Department of Public Health, Faculty of Medicine, University of Tokyo, (Japan))

    1991-01-01

    To investigate the effects of styrene exposure on peripheral, central, and autonomic nervous system functions in man, we measured the distribution of nerve conduction velocities (DCV), short-latency somatosensory evoked potentials (SSEP), and variability in electrocardiographic R-R interval (CVRR) as well as conventional sensory and motor median nerve conduction velocities (SCV and MCV) in eleven styrene-exposed workers. The styrene workers' urinary phenylglyoxylic acid levels ranged from 31 to 419 (mean 169) mg/g creatinine at the end of the work shift on the examination day (estimated exposure to styrene of 22 ppm in air). Control subjects, matched to each styrene worker by sex and age, were selected from healthy adults without cardiovascular, neurologic and other potentially confounding disorders. In the styrene workers, we found that the V80 velocity of the DCV, below which 80% of active nerve fibers lie, and the SCV were both significantly slowed; the CVRR was also significantly reduced. There were no significant differences in SSEP latencies, MCV, or heart rate between the exposed workers and controls. These data, despite the small sample size, suggest that styrene affects the faster myelinated fibers of the peripheral sensory nerves, and that it also affects autonomic nervous activity.

  8. Technoeconomic evaluation of bio-based styrene production by engineered Escherichia coli.

    Science.gov (United States)

    Claypool, Joshua T; Raman, D Raj; Jarboe, Laura R; Nielsen, David R

    2014-08-01

    Styrene is an important commodity chemical used in polymers and resins, and is typically produced from the petrochemical feedstocks benzene and ethylene. Styrene has recently been produced biosynthetically for the first time using engineered Escherichia coli, and this bio-based route may represent a lower energy and renewable alternative to petroleum-derived styrene. However, the economics of such an approach has not yet been investigated. Using an early-stage technoeconomic evaluation tool, a preliminary economic analysis of bio-based styrene from C(6)-sugar feedstock has been conducted. Owing to styrene's limited water solubility, it was assumed that the resulting fermentation broth would spontaneously form two immiscible liquid phases that could subsequently be decanted. Assuming current C(6) sugar prices and industrially achievable biokinetic parameter values (e.g., product yield, specific growth rate), commercial-scale bio-based styrene has a minimum estimated selling price (MESP) of 1.90 USD kg(-1) which is in the range of current styrene prices. A Monte Carlo analysis revealed a potentially large (0.45 USD kg(-1)) standard deviation in the MESP, while a sensitivity analysis showed feedstock price and overall yield as primary drivers of MESP.

  9. Experimental vapor-liquid equilibria data for binary mixtures of xylene isomers

    Directory of Open Access Journals (Sweden)

    W.L. Rodrigues

    2005-09-01

    Full Text Available Separation of aromatic C8 compounds by distillation is a difficult task due to the low relative volatilities of the compounds and to the high degree of purity required of the final commercial products. For rigorous simulation and optimization of this separation, the use of a model capable of describing vapor-liquid equilibria accurately is necessary. Nevertheless, experimental data are not available for all binaries at atmospheric pressure. Vapor-liquid equilibria data for binary mixtures were isobarically obtained with a modified Fischer cell at 100.65 kPa. The vapor and liquid phase compositions were analyzed with a gas chromatograph. The methodology was initially tested for cyclo-hexane+n-heptane data; results obtained are similar to other data in the literature. Data for xylene binary mixtures were then obtained, and after testing, were considered to be thermodynamically consistent. Experimental data were regressed with Aspen Plus® 10.1 and binary interaction parameters were reported for the most frequently used activity coefficient models and for the classic mixing rules of two cubic equations of state.

  10. Sustainable Production of o-Xylene from Biomass-Derived Pinacol and Acrolein.

    Science.gov (United States)

    Hu, Yancheng; Li, Ning; Li, Guangyi; Wang, Aiqin; Cong, Yu; Wang, Xiaodong; Zhang, Tao

    2017-07-21

    o-Xylene (OX) is a large-volume commodity chemical that is conventionally produced from fossil fuels. In this study, an efficient and sustainable two-step route is used to produce OX from biomass-derived pinacol and acrolein. In the first step, the phosphotungstic acid (HPW)-catalyzed pinacol dehydration in 1-ethyl-3-methylimidazolium chloride ([emim]Cl) selectively affords 2,3-dimethylbutadiene. The high selectivity of this reaction can be ascribed to the H-bonding interaction between Cl - and the hydroxy group of pinacol. The stabilization of the carbocation intermediate by the surrounding anion Cl - may be another reason for the high selectivity. Notably, the good reusability of the HPW/[emim]Cl system can reduce the waste output and production cost. In the second step, OX is selectively produced by a Diels-Alder reaction of 2,3-dimethylbutadiene and acrolein, followed by a Pd/C-catalyzed decarbonylation/aromatization cascade in a one-pot fashion. The sustainable two-step process efficiently produces renewable OX in 79 % overall yield. Analogously, biomass-derived crotonaldehyde and pinacol can also serve as the feedstocks for the production of 1,2,4-trimethylbenzene. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Selective liquid-liquid extraction of antimony(III from hydrochloric acid media by N-n-octylaniline in xylene

    Directory of Open Access Journals (Sweden)

    M. A. ANUSE

    2004-04-01

    Full Text Available N-n-Octylaniline in xylene was used for the extraction separation of antimony(III from hydrochloric acid media. Antimony(III was extracted quantitatively with 10 mL 4 % N-n-octylaniline in xylene. It was stripped from the organic phase with 0.5 M ammonia and estimated photometrically by the iodide method. The effect of metal ion, acid, reagent concentration and various foreign ions was investigated. The method affords binary and ternary separation of antimony(III from tellurium(IV, selenium(IV, lead(II, bismuth(III, tin(IV, germanium(IV, copper(II, gold(III, iron(III and zinc(II. The method is applicable for the analysis of synthetic mixtures, alloys and semiconductor thin films. It is fast, accurate and precise.

  12. SYNTHESIS OF STYRENE-BUTADIENE STATISTIC COPOLYMERS CONTAINING MAGNESIUM INITIATOR

    Directory of Open Access Journals (Sweden)

    A. V. Firsova

    2015-01-01

    Full Text Available The article discusses the use of organomagnesium initiators in the synthesis of styrene-butadiene random copolymer (SBR obtained solution polymerization and their influence on the properties of rubber. Selected organic magnesium dialkyl initiator is combined with a modifier, which is a mixed alkoxide of an alkali and alkaline earth metals, which allows to control the micr ostructure of the diene polymer and its molecular weight characteristics. Alcohol derivatives selected high-boiling alcohols tetra (hydroxypropyl ethylenediamine (lapromol 294 and tetrahydrofurfuryl alcohol (TGFS. Selection of high-boiling alcohols due to the fact that the destruction of alkoxide with aqueous polymer degassing they do not fall into the return solvent and almost fall into the exact water. The metal components of alkoxides are lithium, sodium, potassium, magnesium and calcium. The resulting solutions are stable when stored modifier t hroughout the year even at -40 °C. The scheme of obtaining the new catalyst systems based organomagnesium and alcoxide of alkali and alkaline earth metals, which yields as functionalized SBR with a statistical and a distribution block of butadiene and styrene was developed. The process of copolymerization with styrene to butadiene organomagnesium initiators as using an organolithium compound (n-butyllithium was carried out, and without it. Found that the addition of n-butyllithium in the reaction mixture leads to a sharp increase in the rate of reaction. The results of studies of the effect of composition of the initiator system on the structure of diene polymers. It was revealed that a mixed initiator system affords a high conversion of monomers (to 90 % in 1 hour 1,2-polybutadiene content increased to 60 %. The process of polymerization of only a mixture of organomagnesium initiators and alcoxide of alkali and alkaline earth metals are not actively proceeds, conversion of the monomers reaches to 90 % in 4 hours, the microstructure

  13. [Hearing impairment in the plastics industry workers exposed to styrene and noise].

    Science.gov (United States)

    Sliwińska-Kowalska, M; Bilski, B; Zamysłowska-Szmytke, E; Kotyło, P; Fiszer, M; Wesołowski, W; Pawlaczyk-Łuszczyńska, M; Kucharska, M; Dudarewicz, A

    2001-01-01

    Styrene exerts ototoxic effect in animals, and the combined exposure to this solvent and noise produces a synergistic effect relative to the isolated exposure to noise. However, there is a lack of reliable evidence that chronic occupational exposure to styrene is ototoxic to humans. Neither has been documented its additive effect with noise. The present study was aimed to assess hearing impairment and the risk of hearing loss in workers exposed to both styrene and noise. The study group included 72 male workers occupationally exposed to styrene in the plastics industry. The results were compared with two control groups, matched by age, gender and personal traits: one group composed of 82 male workers employed in a printing house and exposed only to noise at the levels almost twice as high as those observed in the group exposed to styrene and noise, and the other consisted of 65 male workers exposed neither to solvents nor to noise at workplace. In the group exposed to styrene and noise, significantly increased average hearing loss, as compared to both control groups, was found at all frequencies (1-8 kHz). The risk of hearing loss in the group exposed to styrene and noise was seven times higher (RR: 6.6; 3.0-15.9) than in the non-exposed group, and four times higher (RR: 4.0; 1.8-9.1) than in when workers exposed only to noise. However, no relationship could be observed between the amount of styrene exposure and hearing impairment, taking account of the confounding effect of noise and age. The results of the study suggest that the exposure to solvent mixtures with styrene as a basic component may exert additional, to noise, adverse effect on the auditory organ.

  14. Trends in occupational exposure to styrene in the European glass fibre-reinforced plastics industry.

    Science.gov (United States)

    Van Rooij, J G M; Kasper, A; Triebig, G; Werner, P; Jongeneelen, F J; Kromhout, H

    2008-07-01

    This study presents temporal trends of styrene exposure for workers in the European glass fibre-reinforced plastics (GRP) industry during the period 1966-2002. Data of personal styrene exposure measurements were retrieved from reports, databases and peer-reviewed papers. Only sources with descriptive statistics of personal measurements were accepted. The styrene exposure data cover personal air samples and biological monitoring data, that is, urinary styrene metabolites (mandelic acid and/or phenylglyoxylic acid) and styrene in blood. Means of series of measurements were categorized by year, country, production process, job and sampling strategy. Linear mixed models were used to identify temporal trends and factors affecting exposure levels. Personal exposure measurements were available from 60 reports providing data on 24145 1-8-h time-weighted average shift personal air samples. Available data of biological exposure indicators included measurements of mandelic acid in post-shift urine (6361 urine samples being analysed). Trend analyses of the available styrene exposure data showed that the average styrene concentration in the breathing zone of open-mould workers in the European GRP industry has decreased on average by 5.3% per year during the period 1966-1990 and by only 0.4% annually in the period after 1990. The highest exposures were measured in Southern Europe and the lowest exposures in Northern Europe with Central Europe in between. Biological indicators of styrene (mandelic acid in post-shift urine) showed a somewhat steeper decline (8.9%), most likely because urine samples were collected in companies that showed a stronger decrease of styrene exposure in air than GRP companies where no biological measurements were carried out.

  15. The Effect of Zeolite Structure on the Activity and Selectivity in p-Xylene Alkylation with Isopropyl Alcohol

    Czech Academy of Sciences Publication Activity Database

    Musilová, Zuzana; Kubů, Martin; Burton, A. W.; Zones, S. I.; Voláková, Martina; Čejka, Jiří

    2009-01-01

    Roč. 131, 3-4 (2009), s. 393-400 ISSN 1011-372X R&D Projects: GA AV ČR 1QS400400560; GA ČR GD203/08/H032 Institutional research plan: CEZ:AV0Z40400503 Keywords : SSZ-35 * SSZ-33 * p-xylene * alkylation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.021, year: 2009

  16. Post-Synthesis Modification of SSZ-35 Zeolite to Enhance the Selectivity in p-Xylene Alkylation with Isopropyl Alcohol

    Czech Academy of Sciences Publication Activity Database

    Musilová, Zuzana; Zones, S. I.; Čejka, Jiří

    2010-01-01

    Roč. 53, 3-4 (2010), s. 273-282 ISSN 1022-5528 R&D Projects: GA AV ČR 1QS400400560; GA ČR GD203/08/H032 Institutional research plan: CEZ:AV0Z40400503 Keywords : SSZ-35 * surface modification * p-xylene * 2,5-dimethylcumene Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.359, year: 2010

  17. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

    Directory of Open Access Journals (Sweden)

    S.M. Kemdeo

    2010-10-01

    Full Text Available TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reaction. Catalyst calcined at higher temperatures showed the negative influence on o-xylene conversion and 4-nitro-o-xylene selectivity. Conversion can be correlated with the presence of strong Brönsted acid sites over the catalyst surface whereas change in selectivity was found attributed to the pore diameter of the catalyst. These catalysts also performed satisfactorily, when used for nitration of other aromatics. No use of corrosive sulfuric acid and efficient reusability of the catalyst make the process environmentally friendly and economic. ©2010 BCREC UNDIP. All rights reserved(Received: 9th February 2010, Revised: 5th March 2010; Accepted: 18th March 2010[How to Cite: S.M. Kemdeo, V.S. Sapkal, G.N. Chaudhari. (2010. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene. Bulletin of Chemical Reaction Engineering and Catalysis, 5(1: 39-49. doi:10.9767/bcrec.5.1.7126.39-49][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.5.1.7126.39-49 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/7126 ]Cited by in: Taylor Francis |

  18. Study on the ultrafast dynamics of o-xylene cation by combined fs-photoelectron imaging-photofragmentation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuzhu, E-mail: yuzhu.liu@psi.ch; Radi, Peter; Gerber, Thomas; Knopp, Gregor, E-mail: gregor.knopp@psi.ch

    2014-10-17

    Highlights: • Photoelectron imaging and photofragment spectroscopy are combined. • Photoelectron imaging has been measured to characterize the prepared cation states. • Ultrafast signal decay with time constant of 734 (±61) fs has been observed. - Abstract: Ultrafast dynamics of o-xylene cation has been studied by time resolved fs-photofragmentation (PF) spectroscopy in combination with photoelectron imaging (PEI). In the experiment, multiphoton ionization is used to prepare the o-xylene cation characterized by PEI. The ultrafast dynamics of o-xylene ions are measured by monitoring the time dependent parent-ion depletion and the fragment-ion formation, simultaneously. An ultrafast relaxation time of the parent ion of 734 (±61) fs has been observed. The PEI-PF measurements support the interpretation of this relaxation channel to a combination of internal conversion between the two ionic states (D{sub 0} and D{sub 1}) and intramolecular vibrational-energy redistribution process within the D{sub 0} state.

  19. Evaluating the efficiency of two phase partitioning stirred tank bio-reactor for treating xylene vapors from the airstreamthrough a bed of Pseudomonas Putida

    Directory of Open Access Journals (Sweden)

    F. Golbabaei

    2015-04-01

    Conclusion: Overall, the results of the present research revealed that the application of two phase stirred tank bioreactors (TPPBs containing pure strains of Pseudomonas putida was successful for treatment of air streams with xylene.

  20. The effects of small concentrations of methanol on the radiation polymerization of styrene

    International Nuclear Information System (INIS)

    Tang, Fuh-Wel; Al-Sheikhly, M.; Silverman, J.

    1991-01-01

    The mechanisms whereby ionizing radiation produce the species which initiate neutral free radical and ionic polymerization are investigated. Of particular interest is the remarkable enhancement effect on radiation induced polymerization of styrene by small concentrations of methanol. The approach is to compare the effects of methanol and other alcohols on the steady state polymerization of styrene induced by two different initiation methods: gamma ray; ultraviolet light (UV). In addition to these steady state reaction studies, microsecond pulse radiolysis with 6 MeV electrons is used to study the transient aspects of styrene polymerization and especially, the effect of methanol on the initiaion step. (author) 7 refs.; 6 figs

  1. Kinetics of radiation-induced graft polymerization of styrene onto poly(ethylene oxide)

    International Nuclear Information System (INIS)

    Omichi, H.; Araki, K.

    1979-01-01

    The graft polymerization of styrene onto preirradiated poly(ethylene oxide) was studied. From the measurement of swelling of the polymer in various solvents the solubility parameter of poly(ethylene oxide) was estimated as 9.3. The kinetic analysis of the reaction indicated that the graft polymerization was diffusion controlled. Kinetic parameters of the reaction such as ∫ 0 /sup t/R/sub i/dt, k/sub p/, k/sub tr/, and k/sub t/ were obtained in poly(ethylene oxide)-styrene system and compared with those in poly(isobutylene)-styrene system. 9 figures, 1 table

  2. Simulation of styrene polymerization reactors: kinetic and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    A. S. Almeida

    2008-06-01

    Full Text Available A mathematical model for the free radical polymerization of styrene is developed to predict the steady-state and dynamic behavior of a continuous process. Special emphasis is given for the kinetic and thermodynamic models, where the most sensitive parameters were estimated using data from an industrial plant. The thermodynamic model is based on a cubic equation of state and a mixing rule applied to the low-pressure vapor-liquid equilibrium of polymeric solutions, suitable for modeling the auto-refrigerated polymerization reactors, which use the vaporization rate to remove the reaction heat from the exothermic reactions. The simulation results show the high predictive capability of the proposed model when compared with plant data for conversion, average molecular weights, polydispersity, melt flow index, and thermal properties for different polymer grades.

  3. Polymer degradation during radiation-induced emulsion polymerization of styrene

    International Nuclear Information System (INIS)

    Sato, K.; Rudin, A.; Huang, R.Y.M.

    1976-01-01

    Styrene was polymerized in emulsion with initiation by γ-rays at a dose rate of 0.6 Mrad/hr. Polymerization rates were as expected from previous reports by others. No branching or crosslinking was detectable, and the anti M/sub w//anti M/sub n/ ratio of the polystyrene did not change significantly during the course of the polymerization reaction. The molecular weight of the product polymer decreased with increasing conversion, in contrast to the behavior of chemically initiated emulsion polymerizations. Monomer-free polystyrene does not degrade under the same radiation conditions, and the progressive decrease of polymer molecular weight with conversion is shown to result from the presence of monomer

  4. Interacting Blends of Novel Unsaturated Polyester Amide Resin with Styrene

    Directory of Open Access Journals (Sweden)

    Hasmukh S. Patel

    2004-01-01

    Full Text Available Novel unsaturated poly (ester-amide resins (UPEAs were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA and unsaturated aliphatic bisamic acids using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, Styrene (STY. to produce a homogeneous resin syrup. The curing of these UPEAs-STY. resin blends was carried out by using benzoyl peroxide (BPO as a catalyst and was monitored by using a differential scanning calorimeter (DSC. The glass fibre reinforced composites (i.e. laminates of these UPEA-STY. resin blends were fabricated using the DSC data. The chemical, mechanical and electrical properties of the glass fibre composites have also been evaluated. The unreinforced cured samples of the UPEA-STY. resin blends were also analyzed by thermogravimetry (TGA.

  5. Metabolic interaction between toluene, trichloroethylene and n-hexane in humans

    DEFF Research Database (Denmark)

    Bælum, Jesper; Mølhave, Lars; Hansen, Steen Honoré

    1998-01-01

    OBJECTIVES: This human experimental study describes the mutual metabolic interaction between toluene, trichloroethylene, and n-hexane. METHODS: Eight healthy male volunteers were exposed to combinations of toluene (1.5 or 4 mg/min), trichloroethylene (1.5 or 4 mg/min), and n-hexane (0.3 or 1.0 mg...

  6. Selective alkylation of toluene over basic zeolites: an in situ infrared spectroscopic investigation

    NARCIS (Netherlands)

    Palomares gimeno, A.E.; Palomares, A.E.; Eder-Mirth, G.; Mirth, G.C.; Lercher, J.A.

    1997-01-01

    In situinfrared spectroscopy was used to study the sorption and reaction of toluene and methanol over various alkali exchanged X zeolites. The size of the metal cations controls the preference of sorbing methanol or toluene. The smaller the cation, the higher the preference for methanol is. A

  7. alkylation of toluene over basic catalysts - key requirements for side chain alkylation

    NARCIS (Netherlands)

    Palomares gimeno, A.E.; Palomares, A.E.; Eder-Mirth, G.; Mirth, G.C.; Rep, M.; Rep, M.; Lercher, J.A.

    1998-01-01

    In situinfrared spectroscopy was used to study sorption and reaction of toluene and methanol over various basic catalysts (MgO, hydrotalcites, and basic zeolites). The size of the metal cations controls the preference of sorbing methanol or toluene; i.e., the larger the metal cation, the higher the

  8. Use of Selective Inhibitors and Chromogenic Substrates to Differentiate Bacteria Based on Toluene Oxygenase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Keener, William Kelvin; Schaller, Kastli Dianne; Walton, Michelle Rene; Partin, Judy Kaye; Watwood, Mary Elizabeth; Smith, William Aaron; Chingenpeel, S. R.

    2001-09-01

    In whole-cell studies, two alkynes, 1-pentyne and phenylacetylene, were selective, irreversible inhibitors of monooxygenase enzymes in catabolic pathways that permit growth of bacteria on toluene. 1-Pentyne selectively inhibited growth of Burkholderia cepacia G4 (toluene 2-monooxygenase [T2MO] pathway) and B. pickettii PKO1 (toluene 3-monooxygenase [T3MO] pathway) on toluene, but did not inhibit growth of bacteria expressing other pathways. In further studies with strain G4, chromogenic transformation of a,a,a-Trifluoro-m-cresol (TFC) was irreversibly inhibited by 1-pentyne, but the presence of phenol prevented this inhibition. Transformation of catechol by G4 was unaffected by 1-pentyne. With respect to the various pathways and bacteria tested, phenylacetylene selectively inhibited growth of Pseudomonas mendocina KR1 (toluene 4-monooxygenase [T4MO] pathway) on toluene, but not on p-cresol. An Escherichia coli transformant expressing T4MO transformed indole or naphthalene in chromogenic reactions, but not after exposure to phenylacetylene. The naphthalene reaction remained diminished in phenylacetylene-treated cells relative to untreated cells after phenylacetylene was removed, indicating irreversible inhibition. These techniques were used to differentiate toluene-degrading isolates from an aquifer. Based on data generated with these indicators and inhibitors, along with results from Biolog analysis for sole carbon source oxidation, the groundwater isolates were assigned to eight separate groups, some of which apparently differ in their mode of toluene catabolism.

  9. Toluene biodegradation and biofilm growth in an aerobic fixed-film reactor

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1992-01-01

    Aerobic biodegradation of toluene in a biofilm system was investigated. Toluene is easily biodegradable, like several other aromatic compounds. The degradation was first order at bulk concentrations lower than 0.14 mg/l and zero order above 6–8 mg/l. An average yield coefficient of 1 mg biomass/m...

  10. Toluene-induced, Ca2+-dependent vesicular catecholamine release in rat PC12 cells

    NARCIS (Netherlands)

    Westerink, R.H.S.; Vijverberg, H.P.M.

    2002-01-01

    Acute effects of toluene on vesicular catecholamine release from intact PC12 phaeochromocytoma cells have been investigated using carbon fiber microelectrode amperometry. The frequency of vesicles released is low under basal conditions and is enhanced by depolarization. Toluene causes an increase in

  11. Effect of trichloroethylene on the competitive behavior of toluene-degrading bacteria

    NARCIS (Netherlands)

    Mars, Astrid E.; Prins, Gjalt T.; Wietzes, Pieter; Koning, Wim de; Janssen, Dick B.

    The influence of trichloroethylene (TCE) on a mixed culture of four different toluene-degrading bacterial strains (Pseudomonas putida mt-2, P. putida F1, P. putida GJ31, and Burkholderia cepacia G4) was studied with a fed-batch culture. The strains were competing for toluene, which was added at a

  12. Health risk assessment and applied action level of toluene. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Reed, N.R.; Reed, W.A.; Weir, K.; Encomienda, I.; Beltran, L.M.

    1989-05-16

    The purpose of the document is to provide information on the toxicity of toluene and to estimate Applied Action Levels (AALs) for toluene in water, air, and soil. The information provided will aid the California Dept. of Health Services manage hazardous waste sites and protect the health of California residents.

  13. Detection of Toluene Degradation in Bacteria Isolated from Oil Contaminated Soils

    International Nuclear Information System (INIS)

    Ainon Hamzah; Tavakoli, A.; Amir Rabu

    2011-01-01

    Toluene (C 7 H 8 ) a hydrocarbon in crude oil, is a common contaminant in soil and groundwater. In this study, the ability to degrade toluene was investigated from twelve bacteria isolates which were isolated from soil contaminated with oil. Out of 12 bacterial isolates tested, most of Pseudomonas sp. showed the capability to grow in 1 mM of toluene compared with other isolates on the third day of incubation. Based on enzyme assays towards toluene monooxygenase, Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G were shown to have the highest ability to degrade toluene. The toluene monooxygenase activity was analysed by using two calorimetric methods, Horseradish peroxidase (HRP) and indole-indigo. Both of the methods measured the production of catechol by the enzymatic reaction of toluene monooxygenase. In the HRP assay, the highest enzyme activity was 0.274 U/ mL, exhibited by Pseudomonas aeruginosa UKMP-14T. However, for indole-indigo assay, Bacillus cereus UKMP-6G produced the highest enzyme activity of 0.291 U/ ml. Results from both experiments showed that Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G were able to degrade toluene. (author)

  14. EVALUATING THE NMDA-GLUTAMATE RECEPTOR AS A SITE OF ACTION FOR TOLUENE, IN VIVO

    Science.gov (United States)

    In vitro, toluene disrupts the function of NMDA-glutamate receptors, indicating that effects on NMDA receptor function may contribute to toluene neurotoxicity. NMDA-glutamate receptors are widely present in the visual system and contribute to pattern-elicited visual evoked potent...

  15. Differential cardiac effects in rats exposed to atmospheric smog generated from isoprene versus toluene

    Science.gov (United States)

    The results of this study demonstrate that atmospheric smog generated from both isoprene and toluene cause cardiac effects in rats. In addition, it appears that smog from toluene is more toxic in terms of cardiac arrhythmogenicity. Smog, which is a comple...

  16. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    Directory of Open Access Journals (Sweden)

    G. Sarwar

    2011-03-01

    Full Text Available A new condensed toluene mechanism is incorporated into the Community Multiscale Air Quality Modeling system. Model simulations are performed using the CB05 chemical mechanism containing the existing (base and the new toluene mechanism for the western and eastern US for a summer month. With current estimates of tropospheric emission burden, the new toluene mechanism increases monthly mean daily maximum 8-h ozone by 1.0–3.0 ppbv in Los Angeles, Portland, Seattle, Chicago, Cleveland, northeastern US, and Detroit compared to that with the base toluene chemistry. It reduces model mean bias for ozone at elevated observed ozone concentrations. While the new mechanism increases predicted ozone, it does not enhance ozone production efficiency. A sensitivity study suggests that it can further enhance ozone if elevated toluene emissions are present. While it increases in-cloud secondary organic aerosol substantially, its impact on total fine particle mass concentration is small.

  17. Toluene impurity effects on CO2 separation using a hollow fiber membrane for natural gas

    KAUST Repository

    Omole, Imona C.

    2011-03-01

    The performance of defect-free cross-linkable polyimide asymmetric hollow fiber membranes was characterized using an aggressive feed stream containing up to 1000ppm toluene. The membrane was shown to be stable against toluene-induced plasticization compared with analogs made from Matrimid®, a commercial polyimide. Permeation and sorption analysis suggest that the introduction of toluene vapors in the feed subjects the membrane to antiplasticization, as the permeance decreases significantly (to less than 30%) under the most aggressive conditions tested. Separation efficiencies reflected by permselectivities were less affected. The effect of the toluene on the membrane was shown to be reversible when the toluene was removed. © 2010 Elsevier B.V.

  18. Viscometric study of high-cis polybutadiene in toluene solution

    Directory of Open Access Journals (Sweden)

    Mello Ivana L.

    2006-01-01

    Full Text Available Viscometric measurements, in toluene solution at 30 ºC, were performed with high-cis polybutadiene synthesized by neodymium based catalyst. Six different equations were used to calculate intrinsic viscosities and viscosimetric constant values: Huggins, Kraemer, Martin and Schulz-Blaschke by graphic extrapolation, and Solomon-Ciuta, Deb-Chanterjee and again Schulz-Blaschke, through a single point determination. The molecular weight of the polymers was also determined applying Mark-Houwink-Sakurada equation using the values of intrinsic viscosity obtained by the six equations. The values of intrinsic viscosity and viscosity-average molecular weight obtained by the two methods were compared in order to verify the validity of the single point determination for high-cis polybutadiene.

  19. Offshore experiments on styrene spillage in marine waters for risk assessment.

    Science.gov (United States)

    Fuhrer, Mélanie; Péron, Olivier; Höfer, Thomas; Morrissette, Mike; Le Floch, Stéphane

    2012-07-01

    Within the context of risk evaluation of chemical spillages into the marine environment, this paper reports on an offshore experiment to study the behaviour of styrene spilled into sea under natural conditions and discusses theoretical approaches. Floating structures were used to enclose the spillage and the gaseous cloud formation, and dissolution processes were in situ monitored. The identification of spill risks for man and marine environment through GESAMP's hazard profile is described for styrene: Styrene is rated as a chemical with a significant health hazard that will float but also evaporate. However, monitoring of the water column in the experiments showed that the concentration of styrene in water during the first hour represents 50% of the product spilled. For the potentially exposed public, the GESAMP hazard rating recommends the closure of beaches and evacuation. The risk assessment developed from experimental data confirms this safety advice. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Volatile organic compounds in a residential and commercial urban area with a diesel, compressed natural gas and oxygenated gasoline vehicular fleet.

    Science.gov (United States)

    Martins, Eduardo Monteiro; Arbilla, Graciela; Gatti, Luciana Vanni

    2010-02-01

    Air samples were collected in a typical residential and commercial area in Rio de Janeiro, Brazil, where buses and trucks use diesel and light duty vehicles use compressed natural gas, ethanol, and gasohol (gasoline blended with ethanol) as fuel. A total of 66 C3-C12 volatile organic compounds (VOCs) were identified. The most abundant compounds, on a mass concentration basis, included propane, isobutane, i-pentane, m,p-xylene, 1,3,5-trimethylbenzene, toluene, styrene, ethylbenzene, isopropylbenzene, o-xylene and 1,2,4-trimethylbenzene. Two VOCs photochemical reactivity rankings are presented: one involves reaction with OH and the other involves production of ozone.

  1. 0177 Exposure to styrene and the risk of cancer

    DEFF Research Database (Denmark)

    Christensen, Mette Skovgaard; Hansen, J; Ramlau-Hansen, Cecilia

    2014-01-01

    following occupational styrene exposure. METHOD: The cohort consists of 74 902 workers (84% men) in the Danish reinforced plastics industry, originating from 481 companies ever producing reinforced plastics in Denmark 1964-2009. We identified all workers in the National Supplementary Pension Fund Registry...... observed increased risks for cancers that may be due to confounding from smoking and alcohol. Internal risk assessment that includes historical styrene exposure data will supplement the current findings....

  2. Oxidative pyrolysis of polystyrene into styrene monomers in an autothermal fixed-bed catalytic reactor.

    Science.gov (United States)

    Sun, Hui; Rosenthal, Corey; Schmidt, Lanny D

    2012-10-01

    Styrene monomer recovery: A selective stream of styrene from fast pyrolysis of polystyrene is obtained with an autothermal fixed-bed reactor containing noble-metal (Rh, Pt) catalysts. Autothermal fast pyrolysis of polystyrene is an efficient means of recovering monomers from waste polystyrene in a continuous, high-throughput process without external heating. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Dynamic Evaluation of Acrylonitrile Butadiene Styrene Subjected to High-Strain-Rate Compressive Loads

    Science.gov (United States)

    2014-12-01

    Dynamic Evaluation of Acrylonitrile Butadiene Styrene Subjected to High-Strain-Rate Compressive Loads by Alex Peterson, Ed Habtour, Jaret...Army Research Laboratory Aberdeen Proving Ground, MD 21005-5066 ARL-TN-0648 December 2014 Dynamic Evaluation of Acrylonitrile Butadiene ...Dynamic Evaluation of Acrylonitrile Butadiene Styrene Subjected to High-Strain- Rate Compressive Loads 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  4. Global transcriptional response of solvent-sensitive and solvent-tolerant Pseudomonas putida strains exposed to toluene

    DEFF Research Database (Denmark)

    Molina-Santiago, Carlos; Udaondo, Zulema; Gómez Lozano, María

    2017-01-01

    to reduce toluene membrane permeability. The KT2440 strain activates the TCA cycle to generate energy, while avoiding energy-intensive processes such as flagellar biosynthesis. This suggests that KT2440 responds to toluene by focusing on survival mechanisms. The DOT-T1E strain activates toluene degradation...

  5. Degradation of toluene and trichloroethylene by Burkholderia cepacia G4 in growth-limited fed-batch culture

    NARCIS (Netherlands)

    Mars, Astrid E.; Houwing, Joukje; Dolfing, Jan; Janssen, Dick B.

    Burkholderia (Pseudomonas) cepacia G4 was cultivated in a fed-batch bioreactor on either toluene or toluene plus trichloroethylene (TCE), The culture was allowed to reach a constant cell density under conditions in which the amount of toluene supplied equals the maintenance energy demand of the

  6. Adhesion properties of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based adhesives in the presence of phenol formaldehyde resin

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available The adhesion properties, i. e. viscosity, tack and peel strength of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based pressure-sensitive adhesive was studied using phenol formaldehyde resin as the tackifying resin. Toluene was used as the solvent throughout the experiment. SBR composition in SBR/SMR L blend used was 0, 20, 40, 60, 80, 100%. Three different resin loadings, i. e. 40, 80 and 120 parts per hundred parts of rubber (phr were used in the adhesive formulation. The viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas loop tack and peel strength of paper/polyethylene terephthalate (PET film were measured using a Lloyd Adhesion Tester operating at 30 cm/min. Results indicate that the viscosity of adhesive decreases with increasing % SBR whereas loop tack passes through a maximum value at 20% SBR for all resin loadings. Except for the control sample (without resin, the peel strength shows a maximum value at 60% SBR for the three modes of peel tests. For a fixed % SBR, adhesive sample containing 40 phr phenol formaldehyde resin always exhibits the highest loop tack and peel strength, an observation which is associated to the optimum wettability of adhesive on the substrate.

  7. Miscibility and specific interactions in blends of poly[(styrene-co-(cinnamic acid] with poly(methyl methacrylate and modified poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available The miscibility behavior of poly(styrene-co-cinnamic acid (PSCA with poly(methyl methacrylate (PMMA, poly[(methyl methacrylate-co-(4-vinylpyridine] (PMMA4VP and poly[(methyl methacrylate-co-(2-vinylpyridine] (PMMA2VP was studied. DSC measurements indicated that PSCA23 containing 23 mol% of carboxylic acid units was miscible with PMMA, PMMA2VP and PMMA4VP as established from the observation of a single composition dependent glass transition temperature. Miscibility was induced via hydrogen bonding as evidenced by IR frequency shifts of the hydroxyl stretching vibrations of the acid copolymer in the blends. Interpolymer hydrogen bonding formation within the binary systems was also investigated by viscosimetric study of dilute solutions in toluene. For PMMA/PSCA5 blends the viscosity of the mixtures was close to the weight average viscosities of the individual polymer while for blend solutions of PSCA5 with PMMA2VP and PMMA4VP, the interactions were sufficiently strong to form interpolymer complexes with a decrease in viscosity in comparison to the additivity rule.

  8. Genotoxicity of styrene oligomers extracted from polystyrene intended for use in contact with food

    Directory of Open Access Journals (Sweden)

    Makoto Nakai

    2014-01-01

    Full Text Available Here, we conducted in vitro genotoxicity tests to evaluate the genotoxicity of styrene oligomers extracted from polystyrene intended for use in contact with food. Styrene oligomers were extracted with acetone and the extract was subjected to the Ames test (OECD test guideline No. 471 and the in vitro chromosomal aberration test (OECD test guideline No. 473 under good laboratory practice conditions. The concentrations of styrene dimers and trimers in the concentrated extract were 540 and 13,431 ppm, respectively. Extraction with acetone provided markedly higher concentrations of styrene oligomers compared with extraction with 50% ethanol aqueous solution, which is the food simulant currently recommended for use in safety assessments of polystyrene by both the United States Food and Drug Administration and the European Food Safety Authority. And these high concentrations of styrene dimers and trimers were utilized for the evaluation of genotoxicity in vitro. Ames tests using five bacterial tester strains were negative both in the presence or absence of metabolic activation. The in vitro chromosomal aberration test using Chinese hamster lung cells (CHL/IU was also negative. Together, these results suggest that the risk of the genotoxicity of styrene oligomers that migrate from polystyrene food packaging into food is very low.

  9. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

    International Nuclear Information System (INIS)

    Li Xiaomeng; Luan Shifang; Yang Huawei; Shi Hengchong; Zhao Jie; Jin Jing; Yin Jinghua; Stagnaro, Paola

    2012-01-01

    Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.

  10. Liver function in patients exposed to a toluene in a hydrocarbon processing plant

    International Nuclear Information System (INIS)

    Sanchez, E; Fernandez D'Pool, J.

    1996-01-01

    Since the hepatotoxic role of toluene in exposed workers from the petroleum and petrochemical industries chronically exposed to low concentration has no been entirely dilucidated, this transversal study was undertaken in order to clarify the situation in the local industries. A group of 33 non-exposed men workers of such industries (group control, aged 33.0 +/- 4.88 years) were compared with 33 toluene-exposed men (aged 35.0 +/- 9.33 years) from the related industries, with a minimal of 6 months exposition time to toluene and without liver disease history. In addition to a complete occupational diseases medical history, each subject was tested by both a venous blood sample (to determine prothrombin, total and fractioned bilirubin, total and fractioned proteins, liver enzymes and cholesterol) and urine sample (hippuric acid). Also the environmental concentration of toluene in working areas was determined by gas chromatography, which was below the recommended standard levels in working areas. Although the analyzed parameters were in the normal range, it was observed that those workers with known alcohol ingestion and toluene exposition had several abnormalities. The results of this study confirm that toluene may have a synergistic hepatotoxic effect in toluene-exposed workers that are alcohol consumers. The alcohol in considered as a confounding factor and it is not possible to rule out in the etiology of hepatic changes detected in the study

  11. Microbial characterization of toluene-degrading denitrifying consortia obtained from terrestrial and marine ecosystems.

    Science.gov (United States)

    An, Y-J; Joo, Y-H; Hong, I-Y; Ryu, H-W; Cho, K-S

    2004-10-01

    The degradation characteristics of toluene coupled to nitrate reduction were investigated in enrichment culture and the microbial communities of toluene-degrading denitrifying consortia were characterized by denaturing gradient gel electrophoresis (DGGE) technique. Anaerobic nitrate-reducing bacteria were enriched from oil-contaminated soil samples collected from terrestrial (rice field) and marine (tidal flat) ecosystems. Enriched consortia degraded toluene in the presence of nitrate as a terminal electron acceptor. The degradation rate of toluene was affected by the initial substrate concentration and co-existence of other hydrocarbons. The types of toluene-degrading denitrifying consortia depended on the type of ecosystem. The clone RS-7 obtained from the enriched consortium of the rice field was most closely related to a toluene-degrading and denitrifying bacterium, Azoarcus denitrificians (A. tolulyticus sp. nov.). The clone TS-11 detected in the tidal flat enriched consortium was affiliated to Thauera sp. strain S2 (T. aminoaromatica sp. nov.) that was able to degrade toluene under denitrifying conditions. This indicates that environmental factors greatly influence microbial communities obtained from terrestrial (rice field) and marine (tidal flat) ecosystems.

  12. Analysis of residual toluene in food packaging via headspace extraction method using gas chromatography

    International Nuclear Information System (INIS)

    Lim, Ying Chin; Mohd Marsin Sanagi

    2008-01-01

    Polymeric materials are used in many food contact applications as packaging material. The presence of residual toluene in this food packaging material can migrate into food and thus affect the quality of food. In this study, a manual headspace analysis was successfully designed and developed. The determination of residual toluene was carried out with standard addition method and multiple headspace extraction, MHE) method using gas chromatography-flame ionization detector, GC-FID). Identification of toluene was performed by comparison of its retention time with standard toluene and GC-MS. It was found that the suitable heating temperature was 180 degree Celsius with an optimum heating time of 10 minutes. The study also found that the concentration of residual toluene in multicolored sample was higher compared to mono colored sample whereas residual toluene in sample analyzed using standard addition method was higher compared to MHE method. However, comparison with the results obtained from De Paris laboratory, France found that MHE method gave higher accuracy for sample with low analyte concentration. On the other hand, lower accuracy was obtained for sample with high concentration of residual toluene due to systematic errors. Comparison between determination methods showed that MHE method is more precise compared to standard addition method. (author)

  13. Biodegradation of toluene vapor in coir based upflow packed bed reactor by Trichoderma asperellum isolate.

    Science.gov (United States)

    Gopinath, M; Mohanapriya, C; Sivakumar, K; Baskar, G; Muthukumaran, C; Dhanasekar, R

    2016-03-01

    In the present study, a new biofiltration system involving a selective microbial strain isolated from aerated municipal sewage water attached with coir as packing material was developed for toluene degradation. The selected fungal isolate was identified as Trichoderma asperellum by 16S ribosomal RNA (16S rRNA) sequencing method, and pylogenetic tree was constructed using BLASTn search. Effect of various factors on growth and toluene degradation by newly isolated T. asperellum was studied in batch studies, and the optimum conditions were found to be pH 7.0, temperature 30 °C, and initial toluene concentration 1.5 (v/v)%. Continuous removal of gaseous toluene was monitored in upflow packed bed reactor (UFPBR) using T. asperellum. Effect of various parameters like column height, flow rate, and the inlet toluene concentration were studied to evaluate the performance of the biofilter. The maximum elimination capacity (257 g m(-3) h(-1)) was obtained with the packing height of 100 cm with the empty bed residence time of 5 min. Under these optimum conditions, the T. asperellum showed better toluene removal efficiency. Kinetic models have been developed for toluene degradation by T. asperellum using macrokinetic approach of the plug flow model incorporated with Monod model.

  14. Degradation of chloroanilines by toluene dioxygenase from Pseudomonas putida T57.

    Science.gov (United States)

    Nitisakulkan, Tisana; Oku, Shota; Kudo, Daizo; Nakashimada, Yutaka; Tajima, Takahisa; Vangnai, Alisa S; Kato, Junichi

    2014-03-01

    In this study, we investigated the ability of Pseudomonas putida toluene dioxygenase to oxidize chloroanilines. Toluene-induced P. putida T57 cells degraded 4-chloroaniline (4CA) more rapidly than toluene-non-induced cells, suggesting that toluene dioxygenase pathway was involved in 4CA degradation. Escherichia coli harboring P. putida T57 genes encoding toluene dioxygenase complex (todC1C2BA) showed 4CA degradation activity, demonstrating that toluene dioxygenase oxidizes 4CA. Thin-layer chromatography (TLC) and mass spectrometry (MS) analyses identified 4-chlorocatechol and 2-amino-5-chlorophenol as reaction products, suggesting that toluene dioxygenase catalyzes both 1,2- and 2,3-dioxygenation of 4CA. A plasmid containing the entire tod operon (todC1C2BADE) was introduced to P. putida T57 to enhance its ability to degrade 4CA. Resulting P. putida T57 (pHK-C1C2BADE) showed 250-fold higher 4CA degradation activity than P. putida T57 parental strain. P. putida T57 (pHK-C1C2BADE) degraded 2-chloroaniline (2CA), 3-chloroaniline (3CA), and 3,4-dichloroaniline (34DCA) as well as 4CA, but not 3,5-dichloroaniline (35DCA). The order of the degradation rate was: 4CA > 3CA > 2CA > 34DCA. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    International Nuclear Information System (INIS)

    Chan, Ming-Huan; Chung, Shiang-Sheng; Stoker, Astrid K.; Markou, Athina; Chen, Hwei-Hsien

    2012-01-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-D-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperature, and intracranial self-stimulation (ICSS) thresholds in mice. Additionally, the effects of sarcosine on the behavioral and physiological effects induced by toluene were evaluated. Sarcosine may reverse toluene-induced behavioral manifestations by acting as an NMDA receptor co-agonist and by inhibiting the effects of the type I glycine transporter (GlyT1). Mice were treated with toluene alone or combined with sarcosine pretreatment and assessed for rotarod performance, object recognition memory, rectal temperature, and ICSS thresholds. Toluene dose-dependently induced motor incoordination, recognition memory impairment, and hypothermia and lowered ICSS thresholds. Sarcosine pretreatment reversed toluene-induced changes in rotarod performance, novel object recognition, and rectal temperature but not ICSS thresholds. These findings suggest that the sarcosine-induced potentiation of NMDA receptors may reverse motor incoordination, memory impairment, and hypothermia but not the enhancement of brain stimulation reward function associated with toluene exposure. Sarcosine may be a promising compound to prevent acute toluene intoxications by occupational or intentional exposure. -- Highlights: ► Toluene induces impairments in Rotarod test and novel object recognition test. ► Toluene lowers rectal temperature and ICSS thresholds in mice. ► Sarcosine reverses toluene-induced changes in motor, memory and body temperature. ► Sarcosine pretreatment does not affect toluene

  16. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Ming-Huan [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Institute of Neuroscience, National Changchi University, Taipei, Taiwan (China); Chung, Shiang-Sheng [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Department of Pharmacy, Yuli Veterans Hospital, Hualien, Taiwan (China); Stoker, Astrid K.; Markou, Athina [Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA (United States); Chen, Hwei-Hsien, E-mail: hwei@nhri.org.tw [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Division of Mental Health and Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan (China)

    2012-12-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-D-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperature, and intracranial self-stimulation (ICSS) thresholds in mice. Additionally, the effects of sarcosine on the behavioral and physiological effects induced by toluene were evaluated. Sarcosine may reverse toluene-induced behavioral manifestations by acting as an NMDA receptor co-agonist and by inhibiting the effects of the type I glycine transporter (GlyT1). Mice were treated with toluene alone or combined with sarcosine pretreatment and assessed for rotarod performance, object recognition memory, rectal temperature, and ICSS thresholds. Toluene dose-dependently induced motor incoordination, recognition memory impairment, and hypothermia and lowered ICSS thresholds. Sarcosine pretreatment reversed toluene-induced changes in rotarod performance, novel object recognition, and rectal temperature but not ICSS thresholds. These findings suggest that the sarcosine-induced potentiation of NMDA receptors may reverse motor incoordination, memory impairment, and hypothermia but not the enhancement of brain stimulation reward function associated with toluene exposure. Sarcosine may be a promising compound to prevent acute toluene intoxications by occupational or intentional exposure. -- Highlights: ► Toluene induces impairments in Rotarod test and novel object recognition test. ► Toluene lowers rectal temperature and ICSS thresholds in mice. ► Sarcosine reverses toluene-induced changes in motor, memory and body temperature. ► Sarcosine pretreatment does not affect toluene

  17. Investigating the effect of gas flow rate, inlet ozone concentration and relative humidity on the efficacy of catalytic ozonation process in the removal of xylene from waste airstream

    Directory of Open Access Journals (Sweden)

    H.R. MokaramI

    2010-10-01

    Full Text Available Background and aimsThe catalytic ozonation is an efficient process for the degradation of volatile organic compounds from contaminated air stream. This study was aimed at investigating the efficacy of catalytic ozonation process in removal of xylene from the polluted air stream andthe influence of retention time (gas flow rate, inlet ozone dose and relative humidity on this performanceMethodsthe catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selectedoperational variables.ResultsThe results indicated that the efficiency of catalytic ozonation was greater than that of single adsorption in removal of xylene under similar inlet concentration and relative humidity. We found a significant catalytic effect for activated carbon when used in combination with ozonation process, leading to improvement of xylene removal percentage. In addition, the elimination capacity of the system improved with the increase of inlet ozone dose as well as gas flow rate. The relative humidity showed a positive effect of the xylene removal at the range of 5 to 50%, while the higher humidity (more than 50% resulted in reduction of the performance.ConclusionThe findings of the present work revealed that the catalytic ozonation process can be an efficient technique for treating the air streams containing industrial concentrations of xylene. Furthermore, there is a practical potential to retrofit the present adsorption systems intothe catalytic ozonation simply by coupling them with the ozonation system. the catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selected

  18. Side-chain alkylation of toluene with methanol over Zn-modified KX zeolite

    OpenAIRE

    Song, Lanlan; Yu, Yue; Li, Zhenrong; Guo, Shaoqing; Zhao, Liangfu; Li, Wen

    2014-01-01

    The effect of Zn on side-chain alkylation of toluene with methanol over KX zeolite was investigated. It was found that the addition of Zn with a low content over KX could enhance toluene conversion significantly. In addition, the results showed that the conversion of toluene over ZnKX (0.8 wt. %) catalyst was almost twice as high as that over KX. The catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, NH3-temperature-programmed desorption (TPD), pyridine absorption infr...

  19. Health Risk Assessment of Xylene through Microenvironment Monitoring Data: A Case Study of the Petro-Chemical Industries, Thailand

    Directory of Open Access Journals (Sweden)

    Pensri Watchalayann

    2009-01-01

    Full Text Available In the absence of environmental health epidemiology, risk managers, policy makers and health-care authorities usually rely on estimates of human exposure level of proximity to hazardous waste site or regional ambient air quality data. Based on ambient concentrations without considering time-activity patterns, the estimation of personal exposure may be overor underestimated. Twelve villages surrounding the petro-chemical industries located in the eastern region of Thailand were randomly selected to be a representative study area. In each village, air samples were collected at thirty-one microenvironments including indoor and outdoor of a household and workplace. The time-activity patterns of the commuters were also recorded. The ambient xylene concentrations were determined by thermal desorption gas chromatograhy/mass spectrometry. The indoor samples were determined by gas chromatography flame ionization detector. Commuters living in the vicinity of the industrial areas spent most of the time indoor (93.2%, especially at home (66.8%. Individuals spent a significant fraction of the day indoors. The concentrations of xylene ranged from less than 1 μg/m3 to 291.3 μg/m3. The highest level was found at the auto repair shop (291.3 μg/m3. Given micro-environmental concentrations and activity times, the average concentrations of xylene to which commuters may be exposed daily ranged from 90.62 to 134.75 μg/m3. The long term exposure level via inhalation was found to be very low. Collectively, no hazard was indicated by the hazard quotient and the results were found to be similar in all villages.

  20. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

    OpenAIRE

    S.M. Kemdeo; V.S. Sapkal; G.N. Chaudhari

    2010-01-01

    TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reactio...

  1. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

    OpenAIRE

    S.M. Kemdeo; G.N. Chaudhari; V.S. Sapkal

    2010-01-01

    TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reaction. Cat...

  2. A pharmacokinetic model of styrene inhalation with the fugacity approach.

    Science.gov (United States)

    Paterson, S; Mackay, D

    1986-03-15

    The physiologically based pharmacokinetic model of J. C. Ramsey and M. E. Andersen (1984, Toxicol. Appl. Pharmacol. 73, 159-175) of styrene inhalation in rats, with extrapolation to humans, was reformulated with the chemical equilibrium criterion of fugacity instead of concentration to describe compartment partitioning. Fugacity models have been used successfully to describe environmental partitioning processes which are similar in principle to pharmacokinetic processes. The fugacity and concentration models are mathematically equivalent and produce identical results. The use of fugacity provides direct insights into the relative chemical equilibrium partitioning status of compartments, thus facilitating interpretation of experimental and model data. It can help to elucidate dominant processes of transfer, reaction and accumulation, and the direction of diffusion. Certain model simplifications become apparent in which compartments which remain close to equilibrium may be grouped. Maximum steady-state tissue concentrations for a known exposure may be calculated readily. It is suggested that pharmacokinetic fugacity models can complement conventional concentration models and may facilitate linkage to fugacity models describing environmental sources, pathways, and exposure routes.

  3. Fatigue Characteristics of 3D Printed Acrylonitrile Butadiene Styrene (ABS)

    Science.gov (United States)

    Padzi, M. M.; Bazin, M. M.; Muhamad, W. M. W.

    2017-11-01

    Recently, the use of 3D printer technology has become significant to industries, especially when involving the new product development. 3D printing is a technology, which produces the 3D product or prototype using a layer-by-layer technique. However, there becomes less research on the mechanical performance of the 3D printed component. In the present work, fatigue characteristics of 3D printed specimen have been studied. Acrylonitrile butadiene styrene (ABS) has been chosen as a material research due to its wide applications. Two types of specimen used, which is the 3D printing and moulding specimens. Fused deposition modelling (FDM) technique was used to produce the specimens. The dog bone shape part was produced based on ASTM D638 standard and the tensile test has been carried out to get the mechanical properties. Fatigue test was carried out at 40%, 60% and 80% of the tensile strength. The moulded part shows higher fatigue cycles compared to 3D printed part for all loading percentages. Fatigue lives for 40%, 60% and 80%, were 911, 2645 and 26948 cycles, respectively. The results indicated that 3D printed part has a lower fatigue life, which may not suitable for industrial applications. However, the 3D printed part could be improved by using various parameters and may be introduced in low strength application.

  4. The impact of candle burning during All Saints' Day ceremonies on ambient alkyl-substituted benzene concentrations.

    Science.gov (United States)

    Olszowski, Tomasz; Kłos, Andrzej

    2013-11-01

    Research findings concerning benzene, toluene, ethylobenzene, meta-, para- and ortho-xylene as well as styrene (BTEXS) emission at public cemeteries during All Saints' Day are presented here. Tests were carried out at town-located cemeteries in Opole and Grodków (southern Poland) and, as a benchmark, at the centres of those same towns. The purpose of the study was to estimate BTEXS emissions caused by the candle burning and, equally important to examine, whether emissions generated by the tested sources were similar to the BTEXS emissions generated by road transport. During the festive period, significant increases in benzene concentrations, by 200 % and 144 %, were noted at the cemeteries in Opole and Grodków, as well as in toluene, by 366 % and 342 %, respectively. Styrene concentrations also increased. It was demonstrated that the ratio of toluene to benzene concentrations from emissions caused by the burning candles are comparable to the ratio established for transportation emissions.

  5. Binary and ternary LLE data of the system (ethylbenzene + styrene + 1-ethyl-3-methylimidazolium thiocyanate) and binary VLE data of the system (styrene + 1-ethyl-3-methylimidazolium thiocyanate)

    NARCIS (Netherlands)

    Jongmans, Mark; Schuur, Boelo; de Haan, A.B.

    2012-01-01

    The distillation of close boiling mixtures may be improved by adding a proper affinity solvent, and thereby creating an extractive distillation process. An example of a close boiling mixture that may be separated by extractive distillation is the mixture ethylbenzene/styrene. The ionic liquid

  6. Carbon-14 kinetic isotope effects and mechanisms of addition of 2,4-dinitrobenzenesulfenyl chloride to substituted styrenes-1-14C and styrenes-2-14C

    International Nuclear Information System (INIS)

    Kanska, M.; Fry, A.

    1983-01-01

    As the first reported examples of carbon isotope effects in simple electrophilic addition reactions we have measured the carbon-14 kinetic isotope effects in the addition of 2,4-dinitrobenzenesulfenyl chloride to a series of para-substituted α and β-labeled styrenes in acetic acid at 30.1 0 C: for para substituents Cl, H, and CH 3 the k/ 14 K values for α labeling are 1.027, 1.022, and 1.004, and the k/ 14 k values for β labeling are 1.035, 1.032, and 1.037, all +/-approx.0.004. The kinetics of the reaction were measured for the p-CH 3 O,p-CH 3 , unsubstituted, p-Cl, and m-NO 2 styrenes; electron-donating groups strongly accelerate the reaction, and electron-withdrawing groups retard it. The Hammett plot is curved with p + values ranging from about -4.6 at the electron-donating group (EDG) end to about -1.8 at the electron-withdrawing group (EWG) end. Both the isotope effect and kinetic data, and related data from the literature, are interpreted in terms of a changing mechanism, with the activated complexes of the rate-determining steps having much open carbenium ion (ion pair) character for EDG-substituted styrenes and much cyclic thiiranium io (ion par) character for EWG-substituted styrenes. 1 figure, 2 tables

  7. Optimization of a novel method for determination of benzene, toluene, ethylbenzene, and xylenes in hair and waste water samples by carbon nanotubes reinforced sol-gel based hollow fiber solid phase microextraction and gas chromatography using factorial experimental design.

    Science.gov (United States)

    Es'haghi, Zarrin; Ebrahimi, Mahmoud; Hosseini, Mohammad-Saeid

    2011-05-27

    A novel design of solid phase microextraction fiber containing carbon nanotube reinforced sol-gel which was protected by polypropylene hollow fiber (HF-SPME) was developed for pre-concentration and determination of BTEX in environmental waste water and human hair samples. The method validation was included and satisfying results with high pre-concentration factors were obtained. In the present study orthogonal array experimental design (OAD) procedure with OA(16) (4(4)) matrix was applied to study the effect of four factors influencing the HF-SPME method efficiency: stirring speed, volume of adsorption organic solvent, extraction and desorption time of the sample solution, by which the effect of each factor was estimated using individual contributions as response functions in the screening process. Analysis of variance (ANOVA) was employed for estimating the main significant factors and their percentage contributions in extraction. Calibration curves were plotted using ten spiking levels of BTEX in the concentration ranges of 0.02-30,000ng/mL with correlation coefficients (r) 0.989-0.9991 for analytes. Under the optimized extraction conditions, the method showed good linearity (0.3-20,000ng/L), repeatability, low limits of detections (0.49-0.7ng/L) and excellent pre-concentration factors (185-1872). The best conditions which were estimated then applied for the analysis of BTEX compounds in the real samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Highly efficient high-performance liquid chromatographic separation of xylene isomers and phthalate acid esters on a homemade DUT-67(Zr) packed column.

    Science.gov (United States)

    Chen, Sha; Li, Xiao-Xin; Feng, Fan; Li, Sumei; Han, Jia-Hui; Jia, Zi-Yi; Shu, Lun; Somsundaran, P; Li, Jian-Rong

    2018-04-16

    In this study, the baseline separations of xylene isomers and phthalate acid esters on a homemade DUT-67(Zr) packed column were achieved, respectively. The high selectivity for xylene isomers and phthalate acid esters was obtained with the increase of temperature and decrease of the retention time. The hydrophobicity of xylene isomers and phthalate acid esters caused the different separation time on the DUT-67(Zr) packed column. The relative standard deviation values of retention time, peak area, peak height and half peak width for five repeat separation of the xylene isomers were 0.26-0.35, 2.11-2.26, 1.51-2.03, and 0.29-0.77%, and the values of the phthalate acid esters on DUT-67(Zr) column were 0.1-0.4, 4.4-5.2, 3.9-6.3, and 0.6-2.1%, respectively. The thermodynamic properties indicated that the separation of xylene isomers was controlled by ΔH and ΔS, but the separation of phthalate acid esters was mainly controlled by ΔS. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Diazepam influences urinary bioindicator of occupational toluene exposure.

    Science.gov (United States)

    Silveira, Alberto Thalison; Albuquerque, Ana Carolina Campos; Lepera, José Salvador; Martins, Isarita

    2016-12-01

    In the present study, we investigated the influence of diazepam (DZP) on the excretion of TOL by examining their urinary metabolites, hippuric acid (HA) and ortho-cresol (o-C). Male Wistar rats were exposed to TOL (20ppm) in a nose-only exposure chamber (6h/day, 5days/week for 6 weeks) with simultaneous administration of DZP (10mg/kg/day). Urinary o-C levels were determined by GC-MS, while HA, creatinine (CR), DZP and its metabolite, nordiazepam, were analysed by HPLC-DAD. The results of a Mann-Whitney U test showed that DZP influenced the urinary excretion of o-C (p<0.05). This pioneering study revealed that there was an interaction between DZP and TOL, probably by the inhibition of the CYP isoforms (CYP2B6, CYP2C8, CYP2E1, and CYP1A2) involved in the oxidative metabolism of the solvent. This is relevant information to be considered in the biomonitoring of occupational toluene exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Morphology conserving aminopropyl functionalization of hollow silica nanospheres in toluene

    Science.gov (United States)

    Dobó, Dorina G.; Berkesi, Dániel; Kukovecz, Ákos

    2017-07-01

    Inorganic nanostructures containing cavities of monodisperse diameter distribution find applications in e.g. catalysis, adsorption and drug delivery. One of their possible synthesis routes is the template assisted core-shell synthesis. We synthesized hollow silica spheres around polystyrene cores by the sol-gel method. The polystyrene template was removed by heat treatment leaving behind a hollow spherical shell structure. The surface of the spheres was then modified by adding aminopropyl groups. Here we present the first experimental evidence that toluene is a suitable alternative functionalization medium for the resulting thin shells, and report the comprehensive characterization of the amino-functionalized hollow silica spheres based on scanning electron microscopy, transmission electron microscopy, N2 adsorption, FT-IR spectroscopy, Raman spectroscopy and electrokinetic potential measurement. Both the presence of the amino groups and the preservation of the hollow spherical morphology were unambiguously proven. The introduction of the amine functionality adds amphoteric character to the shell as shown by the zeta potential vs. pH function. Unlike pristine silica particles, amino-functionalized nanosphere aqueous sols can be stable at both acidic and basic conditions.

  11. Toluene pyrolysis studies and high temperature reactions of propargyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Kern, R.D.; Chen, H.; Qin, Z. [Univ. of New Orleans, LA (United States)

    1993-12-01

    The main focus of this program is to investigate the thermal decompositions of fuels that play an important role in the pre-particle soot formation process. It has been demonstrated that the condition of maximum soot yield is established when the reaction conditions of temperature and pressure are sufficient to establish a radical pool to support the production of polyaromatic hydrocarbon species and the subsequent formation of soot particles. However, elevated temperatures result in lower soot yields which are attributed to thermolyses of aromatic ring structures and result in the bell-shaped dependence of soot yield on temperature. The authors have selected several acyclic hydrocarbons to evaluate the chemical thermodynamic and kinetic effects attendant to benzene formation. To assess the thermal stability of the aromatic ring, the authors have studied the pyrolyses of benzene, toluene, ethylbenzene, chlorobenzene and pyridine. Time-of-flight mass spectrometry (TOF) is employed to analyze the reaction zone behind reflected shock waves. Reaction time histories of the reactants, products, and intermediates are constructed and mechanisms are formulated to model the experimental data. The TOF work is often performed with use of laser schlieren densitometry (LS) to measure density gradients resulting from the heats of various reactions involved in a particular pyrolytic system. The two techniques, TOF and LS, provide independent and complementary information about ring formation and ring rupture reactions.

  12. Thermal desorption of toluene from Vanadium-containing catalysts coated onto various carriers

    Directory of Open Access Journals (Sweden)

    Z. Zheksenbaeva

    2012-12-01

    Full Text Available The method temperature-programmed desorption has been studied the state of toluene on the surface-modified vanadium catalysts on different carriers. Among the investigated carriers the most active in the reaction of partial oxidation of toluene is anatase structural titanium dioxide. For the partial oxidation of toluene on modified vanadium-containing catalysts deposited on TiO2 was tested. It was found that on the catalyst 20%V2O5-5%MoO3-2%Sb2O3/TiO2 at a temperature of 673K, volume rate of 15 thousand hours-1 oxidation of toluene is 80% c yield of benzoic acid with a selectivity of  70% of 87.5%.

  13. Breakthrough of toluene vapours in granular activated carbon filled packed bed reactor

    International Nuclear Information System (INIS)

    Mohan, N.; Kannan, G.K.; Upendra, S.; Subha, R.; Kumar, N.S.

    2009-01-01

    The objective of this research was to determine the toluene removal efficiency and breakthrough time using commercially available coconut shell-based granular activated carbon in packed bed reactor. To study the effect of toluene removal and break point time of the granular activated carbon (GAC), the parameters studied were bed lengths (2, 3, and 4 cm), concentrations (5, 10, and 15 mg l -1 ) and flow rates (20, 40, and 60 ml/min). The maximum percentage removal of 90% was achieved and the maximum carbon capacity for 5 mg l -1 of toluene, 60 ml/min flow rate and 3 cm bed length shows 607.14 mg/g. The results of dynamic adsorption in a packed bed were consistent with those of equilibrium adsorption by gravimetric method. The breakthrough time and quantity shows that GAC with appropriate surface area can be utilized for air cleaning filters. The result shows that the physisorption plays main role in toluene removal.

  14. TOXICITY OF AROMATIC AEROBIC BIOTRANSFORMATION PRODUCTS OF TOLUENE TO HELA CELLS

    Science.gov (United States)

    Petroleum contamination of groundwater is widely recognized as a serious environmental problem. Toluene (methylbenzene) occurs naturally in crude oil and is commonly found as a contaminant in the subsurface as a result of waste disposal and storage activities. Biological transf...

  15. Hydrogenation of toluene on Ni-Co-Mo supported zeolite catalysts ...

    African Journals Online (AJOL)

    -a, HY-b and Mordenite were prepared and characterized using many techniques for use as hydrotreating catalysts. In a preliminary investigation, toluene was employed as model compound to test the catalysts in hydrogenation, as a major ...

  16. Psychological autopsy and necropsy of an unusual case of suicide by intravenous toluene

    OpenAIRE

    Ranganath R Kulkarni; R G Hemanth Kumar; Pratibha R Kulkarni; Raghavendra B Kotabagi

    2015-01-01

    Toluene (methylbenzene; volatile hydrocarbon) is an industrial solvent that causes major injury to the lungs; the organ being the first capillary bed encountered. We report an unusual case of suicide by a 24-year-old male, paramedical professional, with fatal outcome within 16 h of intentional, intravenous self-administration of toluene, with clinical presentation of acute respiratory distress syndrome. Psychological autopsy revealed severe depressive disorder and solvent (inhalant) abuse, wi...

  17. Blending Octane Number of Toluene with Gasoline-like and PRF Fuels in HCCI Combustion Mode

    KAUST Repository

    Waqas, Muhammad Umer

    2018-04-03

    Future internal combustion engines demand higher efficiency but progression towards this is limited by the phenomenon called knock. A possible solution for reaching high efficiency is Octane-on-Demand (OoD), which allows to customize the antiknock quality of a fuel through blending of high-octane fuel with a low octane fuel. Previous studies on Octane-on-Demand highlighted efficiency benefits depending on the combination of low octane fuel with high octane booster. The author recently published works with ethanol and methanol as high-octane fuels. The results of this work showed that the composition and octane number of the low octane fuel is significant for the blending octane number of both ethanol and methanol. This work focuses on toluene as the high octane fuel (RON 120). Aromatics offers anti-knock quality and with high octane number than alcohols, this work will address if toluene can provide higher octane enhancement. Our aim is to investigate the impact of three gasoline-like fuels and two Primary Reference Fuels (PRFs). More specifically, fuels are FACE (Fuels for Advanced Combustion Engines) I, FACE J, FACE A, PRF 70 and PRF 84. A CFR engine was used to conduct the experiments in HCCI mode. For this combustion mode, the engine operated at four specific conditions based on RON and MON conditions. The octane numbers corresponding to four HCCI numbers were obtained for toluene concentration of 0, 2, 5, 10, 15 and 20%. Results show that the blending octane number of toluene varies non-linearly and linearly with the increase in toluene concentration depending on the base fuel, experimental conditions and the concentration of toluene. As a result, the blending octane number can range from close to 150 with a small fraction of toluene to a number closer to that of toluene, 120, with larger fractions.

  18. Highly regioselective dinitration of toluene over reusable zeolite H-beta

    OpenAIRE

    Smith, Keith; Alotaibi, Mohammad Hayal H.; El-Hiti, Gamal A.

    2013-01-01

    A nitration system comprising nitric acid, propanoic anhydride and zeolite H-beta has been developed for dinitration of toluene to give 2,4-dinitrotoluene in 98% yield, with a 2,4-:2,6-dinitrotoluene ratio of over 120. This represents the most selective quantitative method for 2,4-dinitration of toluene; the catalyst is re-usable, solvent is not needed and an aqueous work-up is not required.

  19. In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films

    International Nuclear Information System (INIS)

    Chou, Chia-Man; Yeh, Chou-Ming; Chung, Chi-Jen; He, Ju-Liang

    2013-01-01

    Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (ω p ) and para-xylene monomer flow rate (f p ). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use. The results reveal that PPX deposited at high ω p or high f p , in comparison with MS, exhibit better cell proliferation and clearly shows less cell adhesion regardless of ω p and f p . PPX also exhibit a comparatively lower level of platelet adhesion than MS. In the animal study, PPX-coated IGS result in similar local tissue responses at 3, 7 and 28 days (short-term) and 84 days (long-term) after subcutaneous implantation the abdominal wall of rodents compared with respective responses to MS. These results suggest that PPX-coated industrial-grade silicone is one alternative to high cost medical-grade silicone.

  20. In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Chia-Man [Department of Surgery, Taichung Veterans General Hospital, Taiwan, ROC (China); National Yang-Ming University, Taipei, Taiwan, ROC (China); Yeh, Chou-Ming, E-mail: cmchou4301@gmail.com [Taichung Hospital, Department of Health, Executive Yuan, Taiwan, ROC (China); Chung, Chi-Jen [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); He, Ju-Liang [Department of Materials Science and Engineering, Feng Chia University, Taiwan, ROC (China)

    2013-09-01

    Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (ω{sub p}) and para-xylene monomer flow rate (f{sub p}). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use. The results reveal that PPX deposited at high ω{sub p} or high f{sub p}, in comparison with MS, exhibit better cell proliferation and clearly shows less cell adhesion regardless of ω{sub p} and f{sub p}. PPX also exhibit a comparatively lower level of platelet adhesion than MS. In the animal study, PPX-coated IGS result in similar local tissue responses at 3, 7 and 28 days (short-term) and 84 days (long-term) after subcutaneous implantation the abdominal wall of rodents compared with respective responses to MS. These results suggest that PPX-coated industrial-grade silicone is one alternative to high cost medical-grade silicone.

  1. Measurements of secondary organic aerosol from oxidation of cycloalkenes, terpenes, and m-xylene using an Aerodyne aerosol mass spectrometer.

    Science.gov (United States)

    Bahreini, R; Keywood, M D; Ng, N L; Varutbangkul, V; Gao, S; Flagan, R C; Seinfeld, J H; Worsnop, D R; Jimenez, J L

    2005-08-01

    The Aerodyne aerosol mass spectrometer (AMS) was used to characterize physical and chemical properties of secondary organic aerosol (SOA) formed during ozonolysis of cycloalkenes and biogenic hydrocarbons and photo-oxidation of m-xylene. Comparison of mass and volume distributions from the AMS and differential mobility analyzers yielded estimates of "effective" density of the SOA in the range of 0.64-1.45 g/cm3, depending on the particular system. Increased contribution of the fragment at m/z 44, C02+ ion fragment of oxygenated organics, and higher "delta" values, based on ion series analysis of the mass spectra, in nucleation experiments of cycloalkenes suggest greater contribution of more oxygenated molecules to the SOA as compared to those formed under seeded experiments. Dominant negative "delta" values of SOA formed during ozonolysis of biogenics indicates the presence of terpene derivative structures or cyclic or unsaturated oxygenated compounds in the SOA. Evidence of acid-catalyzed heterogeneous chemistry, characterized by greater contribution of higher molecular weight fragments to the SOA and corresponding changes in "delta" patterns, is observed in the ozonolysis of alpha-pinene. Mass spectra of SOA formed during photooxidation of m-xylene exhibit features consistent with the presence of furandione compounds and nitro organics. This study demonstrates that mixtures of SOA compounds produced from similar precursors result in broadly similar AMS mass spectra. Thus, fragmentation patterns observed for biogenic versus anthropogenic SOA may be useful in determining the sources of ambient SOA.

  2. Biofiltration of mixtures of gas-phase styrene and acetone with the fungus Sporothrix variecibatus

    Energy Technology Data Exchange (ETDEWEB)

    Rene, Eldon R.; Spackova, Radka; Veiga, Maria C. [University of La Coruna, Dpt. of Chemical Engineering, Campus da Zapateira, Rua da Fraga, 10, 15008 La Coruna (Spain); Kennes, Christian, E-mail: kennes@udc.es [University of La Coruna, Dpt. of Chemical Engineering, Campus da Zapateira, Rua da Fraga, 10, 15008 La Coruna (Spain)

    2010-12-15

    The biodegradation performance of a biofilter, inoculated with the fungus Sporothrix variecibatus, to treat gas-phase styrene and acetone mixtures under steady-state and transient conditions was evaluated. Experiments were carried out by varying the gas-flow rates (0.05-0.4 m{sup 3} h{sup -1}), leading to empty bed residence times as low as 17.1 s, and by changing the concentrations of gas-phase styrene (0.01-6.3 g m{sup -3}) and acetone (0.01-8.9 g m{sup -3}). The total elimination capacities were as high as 360 g m{sup -3} h{sup -1}, with nearly 97.5% removal of styrene and 75.6% for acetone. The biodegradation of acetone was inhibited by the presence of styrene, while styrene removal was affected only slightly by the presence of acetone. During transient-state experiments, increasing the overall pollutant load by almost 3-fold, i.e., from 220 to 600 g m{sup -3} h{sup -1}, resulted in a sudden drop of removal efficiency (>90-70%), but still high elimination capacities were maintained. Periodic microscopic observations revealed that the originally inoculated Sporothrix sp. remained present in the reactor and actively dominant in the biofilm.

  3. Study of energy transfer to solvent in radiation graft polymerization of styrene onto polyethylene

    International Nuclear Information System (INIS)

    Rabie, A.; Odian, G.

    1977-01-01

    The radiation-initiated graft polymerization of styrene onto polyethylene was studied to determine whether energy transfer to diluent was responsible for the previously observed high orders of dependence of the grafting rate on monomer concentration. n-Octane was used as the diluent instead of benzene. If energy transfer from excited polyethylene to benzene were present, it should not be with n-octane. The percent swelling of polyethylene by various n-octane--styrene mixtures was determined. The compositions of various n-octane--styrene mixtures absorbed inside polyethylene were determined by ultraviolet and refractive index measurements and found to be richer in styrene than the corresponding mixtures in which the polyethylene had been placed. The graft polymerization rates were determined at 0.000761, 0.0371, and 0.213 Mrad/hr and plotted against the inside styrene concentrations on a log-log scale to yield the kinetic orders of dependence of rate on monomer as 2, 3, and 3, respectively. It was concluded that energy transfer to diluent was not responsible for the high-order dependence observed

  4. Hematological findings among styrene-exposed workers in the reinforced plastics industry.

    Science.gov (United States)

    Stengel, B; Touranchet, A; Boiteau, H L; Harousseau, H; Mandereau, L; Hémon, D

    1990-01-01

    A cross-sectional survey of hematological parameters was carried out among 221 workers exposed to styrene in the reinforced plastics industry and 104 controls. Styrene exposure was assessed in both groups by monitoring urinary excretion of styrene metabolites (i.e. mandelic and phenylglyoxylic acids) in post-shift urinary samples collected over five consecutive days. Blood tests were performed with the same counter for all subjects. Information on factors liable to affect hematological parameters was collected from personal questionnaires completed by the workers. Urinary excretion of styrene metabolites varied from 15 to 3740 mg/g creatinine. Exposed subjects exhibited significantly lower mean values of neutrophils and mean corpuscular hemoglobin concentration (MCHC) than controls, and significantly higher mean values for monocytes and mean corpuscular volume. A dose-effect relationship was found for MCHC which decreased with urinary metabolite concentrations. These results remained statistically significant for all parameters after adjustment for age, sex, tobacco and alcohol consumption, place of residence (rural or urban) and time of blood sampling (morning or afternoon) with the exception of neutrophils whose relationship with exposure was essentially explained by smoking. These results are suggestive of a direct effect of styrene-exposure--in the range considered--on the statistical distribution of some hematological parameters.

  5. Uptake of toluene and ethylbenzene by plants: removal of volatile indoor air contaminants.

    Science.gov (United States)

    Sriprapat, Wararat; Suksabye, Parinda; Areephak, Sirintip; Klantup, Polawat; Waraha, Atcharaphan; Sawattan, Anuchit; Thiravetyan, Paitip

    2014-04-01

    Air borne uptake of toluene and ethylbenzene by twelve plant species was examined. Of the twelve plant species examined, the highest toluene removal was found in Sansevieria trifasciata, while the ethylbenzene removal from air was with Chlorophytum comosum. Toluene and ethylbenzene can penetrate the plant׳s cuticle. However, the removal rates do not appear to be correlated with numbers of stomata per plant. It was found that wax of S. trifasciata and Sansevieria hyacinthoides had greater absorption of toluene and ethylbenzene, and it contained high hexadecanoic acid. Hexadecanoic acid might be involved in toluene and ethylbenzene adsorption by cuticles wax of plants. Chlorophyll fluorescence analysis or the potential quantum yield of PSII (Fv/Fm) in toluene exposed plants showed no significant differences between the control and the treated plants, whereas plants exposed to ethylbenzene showed significant differences or those parameters, specifically in Dracaena deremensis (Lemon lime), Dracaena sanderiana, Kalanchoe blossfeldiana, and Cordyline fruticosa. The Fv/Fm ratio can give insight into the ability of plants to tolerate (indoor) air pollution by volatile organic chemicals (VOC). This index can be used for identification of suitable plants for treating/sequestering VOCs in contaminated air. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. An isotope dilution gas chromatography/mass spectrometry method for trace analysis of xylene and its metabolites in tissues following threshold limit value exposures

    International Nuclear Information System (INIS)

    Pyon, K.H.; Kracko, D.A.; Strunk, M.R.

    1995-01-01

    The existence of a nose-brain barrier that functions to protect the central nervous system (CNS) from inhaled toxicants has been postulated. Just as a blood-brain barrier protects the CNS from systemic toxicants, the nose-brain barrier may have similar characteristic functions. One component of interest is nasal xenobiotic metabolism and its effect on the transport of pollutants into the CNS at environmentally plausible levels of exposure. Previous results have shown that inhaled xylene are dimethyl phenol (DMP) and methyl benzyl alcohol (MBA), and the nonvolatile metabolites are toluic acid (TA) and methyl hippuric acid (MHA). The nonvolatile metabolites of xylene, along with a small quantity of volatiles, representing either parent xylene or volatile metabolites, are transported via the olfactory epithelium to the glomeruli within the olfactory bulbs of the brain. Further work will be done to establish the linearity for each analyte at the actual highest detection limit of the GC/MS

  7. An isotope dilution gas chromatography/mass spectrometry method for trace analysis of xylene and its metabolites in tissues following threshold limit value exposures

    Energy Technology Data Exchange (ETDEWEB)

    Pyon, K.H.; Kracko, D.A.; Strunk, M.R. [and others

    1995-12-01

    The existence of a nose-brain barrier that functions to protect the central nervous system (CNS) from inhaled toxicants has been postulated. Just as a blood-brain barrier protects the CNS from systemic toxicants, the nose-brain barrier may have similar characteristic functions. One component of interest is nasal xenobiotic metabolism and its effect on the transport of pollutants into the CNS at environmentally plausible levels of exposure. Previous results have shown that inhaled xylene are dimethyl phenol (DMP) and methyl benzyl alcohol (MBA), and the nonvolatile metabolites are toluic acid (TA) and methyl hippuric acid (MHA). The nonvolatile metabolites of xylene, along with a small quantity of volatiles, representing either parent xylene or volatile metabolites, are transported via the olfactory epithelium to the glomeruli within the olfactory bulbs of the brain. Further work will be done to establish the linearity for each analyte at the actual highest detection limit of the GC/MS.

  8. Proton conducting sulphonated fluorinated poly(styrene) crosslinked electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Soules, A.; Ameduri, B.; Boutevin, B.; David, G. [Institut Charles Gerhardt UMR CNRS 5253 Equipe, Ingenierie et Architectures Macromoleculaires,' ' Ecole Nationale Superieure de Chimie de Montpellier, 8 rue de l' Ecole Normale, 34296 Montpellier, Cedex 05 (France); Perrin, R. [CEA Le Ripault Departement des Materiaux, DMAT/SCMF/LSTP, BP16 - 37260 Monts (France); Gebel, G. [Structure et Proprietes des Architectures Moleculaires UMR 5819 (CEA-CNRS-UJF), INAC, SPrAM, CEA Grenoble, 17 Rue des Martyrs, 38054 Grenoble, Cedex 9 (France)

    2011-10-15

    Potential membranes for polymer electrolyte membrane fuel cell based on crosslinked sulphonated fluorinated polystyrenes (PS) were synthesised in two steps. First, azide-telechelic polystyrene was obtained by iodine transfer polymerisation of styrene in the presence of 1,6-diiodoperfluorohexane followed by azido chain-end functionalisation. Then azide-telechelic polystyrene was efficiently crosslinked with 1,10-diazido-1H,1H,2H,2H,9H,9H,10H,10H-perfluorodecane under UV irradiation. After 45 min only, almost completion of azide crosslinking could be achieved, resulting in crosslinked membranes with insoluble fractions higher than 95%. The sulphonation of the crosslinked membranes afforded ionic exchange capacities (IECs) ranging from 2.2 to 3.2 meq g{sup -1}. The hydration number was shown to be very high (from 30 to 75), depending on both the content of perfluorodecane and of sulphonic acid groups. The morphology of the membranes, assessed by small-angle X-ray scattering, was found to be a lamellar-type structure with two types of ionic domains. For the membrane that exhibited an IEC value of 2.2 meq.g{sup -1}, proton conductivity was in the same range as that of Nafion {sup registered} (120-135 mS.cm{sup -1}), whereas the membrane IEC value of 3.2 meq.g{sup -1} showed a proton conductivity higher than that of Nafion {sup registered} in liquid water from 25 to 80 C, though a high water uptake. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Grafting titanium nitride surfaces with sodium styrene sulfonate thin films

    Science.gov (United States)

    Zorn, Gilad; Migonney, Véronique; Castner, David G.

    2014-01-01

    The importance of titanium nitride lies in its high hardness and its remarkable resistance to wear and corrosion, which has led to its use as a coating for the heads of hip prostheses, dental implants and dental surgery tools. However, the usefulness of titanium nitride coatings for biomedical applications could be significantly enhanced by modifying their surface with a bioactive polymer film. The main focus of the present work was to graft a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film from titanium nitride surfaces via a two-step procedure: first modifying the surface with 3-methacryloxypropyltrimethoxysilane (MPS) and then grafting the pNaSS film from the MPS modified titanium through free radical polymerization. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used after each step to characterize success and completeness of each reaction. The surface region of the titanium nitride prior to MPS functionalization and NaSS grafting contained a mixture of titanium nitride, oxy-nitride, oxide species as well as adventitious surface contaminants. After MPS functionalization, Si was detected by XPS, and characteristic MPS fragments were detected by ToF-SIMS. After NaSS grafting, Na and S were detected by XPS and characteristic NaSS fragments were detected by ToF-SIMS. The XPS determined thicknesses of the MPS and NaSS overlayers were ∼1.5 and ∼1.7 nm, respectively. The pNaSS film density was estimated by the toluidine blue colorimetric assay to be 260 ± 70 ng/cm2. PMID:25280842

  10. Application of Lignin as Antioxidant in Styrene Butadiene Rubber Composite

    Science.gov (United States)

    Liu, Shusheng; Cheng, Xiansu

    2010-11-01

    Lignin isolated from enzymatic hydrolyzed cornstalks (EHL) is a renewable natural polymer, and rubber is one of the most important polymer materials. The application of EHL in rubber industry is of great significance. The influence of EHL and antioxidant RD on the vulcanizing characteristics, thermal oxidative aging stability under free condition, and water extraction resistance of styrene-butadiene rubber (SBR) were investigated. The effect of EHL/antioxidant D composite antioxidant on the thermal oxidative ageing of SBR was also evaluated. Results showed that the protection of SBR from thermal oxidative aging by EHL/antioxidant D composite antioxidant was superior to that of antioxidant D. This is because EHL molecules have hindered phenol group and have excellent auxiliary antioxidant role with antioxidant D. Moreover, the influence of EHL on the vulcanizing characteristics of SBR compounds was better than that of antioxidant RD, and EHL can reduce the cure rate and increase the optimum cure time. It is because that the EHL molecules have hindered phenol group and methoxy group, which can form a special structure to capture free radical and terminate the chain reaction. The retained tensile strength of SBR compounds with EHL was similar to that of the samples with antioxidant RD, while the retained elongation at break of SBR compounds with EHL was higher than that of the samples with antioxidant RD. In addition, the SBR compounds with EHL have a good water extraction resistance property, which was similar to the samples with antioxidant RD. This is because EHL have large molecular weight, good stability and low solubility in water. In conclusion, due to the low price, abundant resources, non-toxic and pollution-free, etc., EHL will have broad application prospect.

  11. Effects of toluene on protein synthesis and the interaction with ethanol in hepatocytes isolated from fed and fasted rats

    International Nuclear Information System (INIS)

    Smith-Kielland, A.; Ripel, Aa.; Gadeholt, G.

    1989-01-01

    The effects of three different concentrations (about 20, 100 and 1000 μM) of toluene on protein synthesis were studied in hepatocytes isolated from fed and fasted rats after 60 and 120 min. of incubation. The interaction between ethanol (60 mM) and the low and high toluene concentrations were also tested. To measure protein synthesis, 14 C-valine was used as the precursor amino acid. Total valine concentration was 2 mM to ensure near-constant specific radioactivity of precursor. Toluene concentrations were measured by head-space gas chromatography. Protein synthesis was unchanged in the presence of low toluene concentrations. Intermediate toluene concentration decreased protein synthesis by about 20% and high toluene concentration decreased protein synthesis by about 60%. Protein synthesis was similar in cells from fed and fasted rats. Ethanol alone inhibited protein synthesis by 20-30%, more in fasted than in fed rats. Toluene and ethanol in combination inhibited protein synthesis additively. The high toluene concentration with or without ethanol appeared to inhibit synthesis/secretion of export proteins in hepatocytes from fasted rats. In conclusion, our study indicates that toluene in relatively high concentrations inhibits general protein synthesis in isolated rat hepatocytes. Toluene and ethanol seems to inhibit protein synthesis additively. (author)

  12. The effects of toluene plus noise on hearing thresholds: an evaluation based on repeated measurements in the German printing industry.

    Science.gov (United States)

    Schäper, Michael; Seeber, Andreas; van Thriel, Christoph

    2008-01-01

    The ototoxicity of occupational exposure to toluene plus noise was investigated in a longitudinal study in rotogravure printing and existing findings in the literature were evaluated. The study comprised four repeated examinations during 5 years and started with 333 male workers. Lifetime weighted average exposures (LWAE) to toluene and noise were determined from individual work histories and historic recordings; recent individual exposures were measured 10 times during the study (toluene, active sampling; noise, stationary measurements). Auditory thresholds were measured with pure tone audiometry at 0.125, 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12 kHz. Mean LWAE exposures to toluene and noise were 45+/-17 ppm plus 82+/-7 dB(A) for high toluene exposed and 10+/-7 ppm plus 82+/-4 dB(A) for low toluene exposed subjects, mean current exposures were 26+/-20 ppm plus 81+/-4 dB(A) and 3+/-3 ppm plus 82+/-4 dB(A). Mean exposure duration was 21.3+/-6.5 years for long exposed and 5.9+/-2.2 years for short exposed subjects. Repeated measurement analyses of variance did not reveal effects of toluene intensity, exposure duration and interactions between toluene intensity and noise intensity. Noise intensity [79+/-3 dB(A) vs. 84+/-1 dB(A)] was significant for auditory thresholds. A case concept utilising developments of individual auditory thresholds did not reveal significant toluene effects. Logistic models including age, exposure duration, toluene in ambient air, current noise and either hippuric acid or ortho-cresol (o-cresol) found only age to be significant for elevated OR of high frequency hearing loss. Due to missing toluene effects, it was concluded that the threshold level for developing hearing loss as a result of occupational exposure to toluene plus noise might be above the current limit of 50 ppm toluene.

  13. Effects of Isoprene- and Toluene-Generated Smog on Allergic ...

    Science.gov (United States)

    Reactions of organic compounds with nitric oxide (NO) and sunlight produce complex mixtures of pollutants including secondary organic aerosol (SOA), ozone (O3), nitrogen dioxide (NO2), and reactive aldehydes. The health effects of these photochemical smog mixtures in susceptible populations including asthmatics are unclear. We assessed effects of smog generated from mixtures of NO with isoprene (IS) or toluene (TL) on allergic inflammatory responses in Balb/cJ mice. House dust mite (HDM)-sensitized or control mice were all challenged with HDM intranasally 1 d prior to whole-body inhalation exposure to IS (chamber average 509 ppb NO2, 246 ppb O3, and 160 g/m3 SOA), TL (217 ppb NO2, 129 ppb O3, and 376 g/m3 SOA), or HEPA-filtered air (4 h/d for 2 days). Mice were necropsied within 3 h after the second exposure (2 d post-HDM challenge). Assessment of breathing parameters during exposure with double-chamber plethysmography showed a trend for increased specific airway resistance and decreased minute volume during the second day of TL exposure in both non-allergic and HDM-allergic mice. HDM-allergic air-exposed mice had significant increases in numbers of bronchoalveolar lavage (BAL) alveolar macrophages (AM) and eosinophils (EO), and trends for increases in BAL indices of lung injury in comparison with non-allergic air-exposed mice. Exposure to either IS or TL attenuated the increases in AM, EO, and lung injury markers in HDM-allergic mice. The results of this

  14. Exposure to the Abused Inhalant Toluene Alters Medial Prefrontal Cortex Physiology.

    Science.gov (United States)

    Wayman, Wesley N; Woodward, John J

    2018-03-01

    Inhalants, including toluene, target the addiction neurocircuitry and are often one of the first drugs of abuse tried by adolescents. The medial prefrontal cortex (mPFC) is involved in regulating goal-directed/reward-motivated behaviors and different mPFC sub-regions have been proposed to promote (prelimbic, PRL) or inhibit (infralimbic, IL) these behaviors. While this dichotomy has been studied in the context of other drugs of abuse, it is not known whether toluene exposure differentially affects neurons within PRL and IL regions. To address this question, we used whole-cell electrophysiology and determined the intrinsic excitability of PRL and IL pyramidal neurons in adolescent rats 24 h following a brief exposure to air or toluene vapor (10 500 p.p.m.). Prior to exposure, fluorescent retrobeads were injected into the NAc core (NAcc) or shell (NAcs) sub-regions to identify projection-specific mPFC neurons. In toluene treated adolescent rats, layer 5/6 NAcc projecting PRL (PRL5/6) neurons fired fewer action potentials and this was associated with increased rheobase, increased spike duration, and reductions in membrane resistance and amplitude of the I h current. No changes in excitability were observed in layer 2/3 NAcc projecting PRL (PRL2/3) neurons. In contrast to PRL neurons, layer 5 IL (IL5) and layer 2/3 (IL2/3) NAcc projecting neurons showed enhanced firing in toluene-exposed animals and in IL5 neurons, this was associated with a reduction in rheobase and AHP. For NAcs projecting neurons, toluene exposure significantly decreased firing of IL5 neurons and this was accompanied by an increased rheobase, increased spike duration, and reduced I h amplitude. The intrinsic excitability of PRL5, PRL2/3, and IL2/3 neurons projecting to the NAcs was not affected by exposure to toluene. The changes in excitability observed 24 h after toluene exposure were not observed when recordings were performed 7 days after the exposure. Finally, there were no changes in

  15. An SOA model for toluene oxidation in the presence of inorganic aerosols.

    Science.gov (United States)

    Cao, Gang; Jang, Myoseon

    2010-01-15

    A predictive model for secondary organic aerosol (SOA) formation including both partitioning and heterogeneous reactions is explored for the SOA produced from the oxidation of toluene in the presence of inorganic seed aerosols. The predictive SOA model comprises the explicit gas-phase chemistry of toluene, gas-particle partitioning, and heterogeneous chemistry. The resulting products from the explicit gas phase chemistry are lumped into several classes of chemical species based on their vapor pressure and reactivity for heterogeneous reactions. Both the gas-particle partitioning coefficient and the heterogeneous reaction rate constant of each lumped gas-phase product are theoretically determined using group contribution and molecular structure-reactivity. In the SOA model, the predictive SOA mass is decoupled into partitioning (OM(P)) and heterogeneous aerosol production (OM(H)). OM(P) is estimated from the SOA partitioning model developed by Schell et al. (J. Geophys. Res. 2001, 106, 28275-28293 ) that has been used in a regional air quality model (CMAQ 4.7). OM(H) is predicted from the heterogeneous SOA model developed by Jang et al. (Environ. Sci. Technol. 2006, 40, 3013-3022 ). The SOA model is evaluated using a number of the experimental SOA data that are generated in a 2 m(3) indoor Teflon film chamber under various experimental conditions (e.g., humidity, inorganic seed compositions, NO(x) concentrations). The SOA model reasonably predicts not only the gas-phase chemistry, such as the ozone formation, the conversion of NO to NO(2), and the toluene decay, but also the SOA production. The model predicted that the OM(H) fraction of the total toluene SOA mass increases as NO(x) concentrations decrease: 0.73-0.83 at low NO(x) levels and 0.17-0.47 at middle and high NO(x) levels for SOA experiments with high initial toluene concentrations. Our study also finds a significant increase in the OM(H) mass fraction in the SOA generated with low initial toluene

  16. IMPACT OF AN OZONE GENERATOR AIR CLEANER ON STYRENE CONCENTRATIONS IN AN INDOOR AIR QUALITY RESEARCH CHAMBER

    Science.gov (United States)

    The paper gives results of an investigation of the impact of an ozone generator air cleaner on vapor-phase styrene concentrations in a full-scale indoor air quality test chamber. The time history of the concentrations of styrene and ozone is well predicted by a simulation model u...

  17. Reduced production of anti-inflammatory soluble HLA-G molecules in styrene exposed workers.

    Science.gov (United States)

    Rizzo, Roberta; Quintavalle, Sonia; Stignani, Marina; Franzè, Fabrizio; Melchiorri, Loredana; De Rosa, Edoardo; Baricordi, Olavio R

    2009-03-01

    HLA-G antigens are non-classical HLA-class I anti-inflammatory molecules. Since styrene exposure has been suggested to induce immune alteration, we analyzed plasma levels and "in vitro" peripheral blood mononuclear cell (PBMC) production of soluble HLA-G (sHLA-G) and interleukin-10 (IL-10) molecules after lipopolysaccharide (LPS) stimulation, in styrene exposed workers and healthy subjects. Exposed workers showed reduced plasma levels of sHLA-G and IL-10 in comparison to healthy controls. Similarly, lower levels of sHLA-G and IL-10 molecules were observed in PBMC culture supernatants after LPS activation. These data propose styrene exposure as a mediator of impaired sHLA-G production. Copyright © 2008 Elsevier B.V. All rights reserved.

  18. Effects of surfactants on the properties of mortar containing styrene/methacrylate superplasticizer.

    Science.gov (United States)

    Negim, El-Sayed; Kozhamzharova, Latipa; Khatib, Jamal; Bekbayeva, Lyazzat; Williams, Craig

    2014-01-01

    The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA.

  19. Effects of solvent polarity on mutual styrene grafting onto polypropylene by electron beam irradiation

    International Nuclear Information System (INIS)

    Moura, E.; Manzoli, J.E.; Geraldo, A.B.C.

    2012-01-01

    Radiation induced mutual grafting of styrene onto polypropylene has been carried using several grafting solutions with different organic solvents and polarity levels. In the mixture of styrene and protic polar solvents high grafting yields were obtained. This behavior suggests that grafting process does not have dependence on swelling of the substrate, something that is expected when a non-polar substrate and a non-polar media are in contact. In this case, the grafting yield may be related to the free radical generation at protic polar solvent; these reactive specimens start the reaction on substrate surface to allow the accessibility of monomer species to active sites. Some reaction mechanisms are proposed. - Highlights: ► Styrene grafting is performed with high yield when protic polar solvents are used. ► Results are related to effects from electron solvation and dipole interactions. ► Grafting samples performed in n-octanol mixtures had crystallinity changes.

  20. Hydrogenation of Styrene Oxide to 2-Phenylethanol over Nanocrystalline Ni Prepared by Ethylene Glycol Reduction Method

    Directory of Open Access Journals (Sweden)

    Sunil K. Kanojiya

    2014-01-01

    Full Text Available Nanocrystalline nickel prepared by glycol reduction method and characterized by XRD and magnetic measurements has been used as a catalyst for hydrogenation of styrene oxide to 2-phenylethanol. Effect of process variables such as particle size of the catalyst, temperature, and pressure have been optimized to achieve a maximum conversion of 98% of styrene oxide with 99% selectivity towards 2-phenylethanol. The structure of the transition state has been computed employing density functional theory and using Gaussian 09 suite. The enthalpy of reaction (ΔH and activation energy (Ea are calculated to be 85.3 kcal·mol−1 and 123.03 kcal·mol−1, respectively. A tentative mechanism for the reaction is proposed according to which atomized hydrogen and styrene oxide react together over the catalyst surface to produce 2-phenylethanol.

  1. Solid radiation curable polyene compositions containing liquid polythiols and solid styrene-allyl copolymer based polyenes

    International Nuclear Information System (INIS)

    Morgan, C.R.

    1977-01-01

    Novel styrene-allyl alcohol copolymer based solid polyene compositions which when mixed with liquid polythiols can form solid curable polyene-polythiol systems are claimed. These solid polyenes, containing at least two reactive carbon-to-carbon unsaturated bonds, are urethane or ester derivatives of styrene-allyl alcohol copolymers. The solid polyenes are prepared by treating the hydroxyl groups of a styrene-allyl alcohol copolymer with a reactive unsaturated isocyanate, e.g., allyl isocyanate or a reactive unsaturated carboxylic acid, e.g., acrylic acid. Upon exposure to a free radical generator, e.g., actinic radiation, the solid polyene-polythiol compositions cure to solid, insoluble, chemically resistant, cross-linked polythioether products. Since the solid polyene-liquid polythiol composition can be cured in a solid state, such a curable system finds particular use in preparation of coatings, imaged surfaces such as photoresists, particularly solder-resistant photoresists, printing plates, etc

  2. Selective and Stable Ethylbenzene Dehydrogenation to Styrene over Nanodiamonds under Oxygen-lean Conditions.

    Science.gov (United States)

    Diao, Jiangyong; Feng, Zhenbao; Huang, Rui; Liu, Hongyang; Hamid, Sharifah Bee Abd; Su, Dang Sheng

    2016-04-07

    For the first time, significant improvement of the catalytic performance of nanodiamonds was achieved for the dehydrogenation of ethylbenzene to styrene under oxygen-lean conditions. We demonstrated that the combination of direct dehydrogenation and oxidative dehydrogenation indeed occurred on the nanodiamond surface throughout the reaction system. It was found that the active sp(2)-sp(3) hybridized nanostructure was well maintained after the long-term test and the active ketonic carbonyl groups could be generated in situ. A high reactivity with 40% ethylbenzene conversion and 92% styrene selectivity was obtained over the nanodiamond catalyst under oxygen-lean conditions even after a 240 h test, demonstrating the potential of this procedure for application as a promising industrial process for the ethylbenzene dehydrogenation to styrene without steam protection. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Preparation and characteristics of acrylic acid/styrene composite plasma polymerized membranes

    Science.gov (United States)

    Jiang, Zhongqing; Jiang, Zhong-jie; Shi, Yicai; Meng, Yuedong

    2010-08-01

    Plasma polymerization has gained increasing interest for the deposition of functional plasma-polymerized membranes suitable for a wide range of applications on account of its advantageous features. In this work, acrylic acid/styrene composite plasma polymerized membranes were synthesized by plasma polymerization of a mixture of acrylic acid and styrene monomers in a low-frequency after-glow capacitively coupled plasma (CCP) discharge process. The structure and composition of the plasma polymerized membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that the partial pressure ratio between acrylic acid (AA) and styrene (St), applied discharge power and the energy of the extracted particles have considerable effects on the structure and the content of functional groups of the deposited membranes.

  4. Adsorption of xylene para- and meta- isomers in NaX and BaX zeolites. Study of properties-structure relations; Adsorption des isomeres para- et meta- du xylene dans les zeolithes NaX et BaX. Etude des relations proprietes-structure

    Energy Technology Data Exchange (ETDEWEB)

    Descours, A.

    1997-02-14

    The separation of para-xylene from C8 aromatics is performed industrially bu adsorption process on zeolitic molecular sieves. The sorption properties of these zeolites are strongly linked to their structure, and their comprehension require an accurate knowledge of the interactions between sorbate molecules and zeolitic structure. The aim of this work is to characterise from a structural point of view the adsorption of para- and meta-xylenes in BaX and NaX zeolites. The former is selective for para-xylene, and the latter has not selective properties for para- and meta-isomers of xylene. For each zeolite, the adsorption of pure para-xylene and meta-xylene or a mixture of the two isomers, is investigated as a function of coverage. Powder neutron diffraction is used to determine the crystalline structure of these zeolites and the different crystallographic adsorption sites of the molecules. The influence of coverage on sorbate-sorbent and sorbate-sorbate interactions is investigated. Infrared spectroscopy allows to determine the chemical environment of the sorbate molecules at low coverage or when the coverage increases, and is particularly effective for the study of the binary mixture of xylenes. This study is performed by sorbing a mixture of xylene isomers, or by sorbing these isomers successively. Infrared studies and crystallographic analysis are compared in order to get a consistent description of adsorption mechanism of xylene isomers for both zeolites as a function of coverage. The role of coverage, of cation type, an the presence of the two xylene isomers is the super-cages is essential. For both zeolites, the increase of coverage actually leads to steric hindrances between sorbed molecules and molecular rearrangements. These reorganizations are connected to the cationic distribution of NaX and BaX zeolites. The sorbed molecules are connected to the cationic distribution of NaX and BaX zeolites. The sorbed molecules are particularly confined in BaX zeolite

  5. A Study of the Patterns, Stoichiometry, and Kinetics of Microbial BTX Degradation Under Denitrifying Conditions by an Activated Sludge Consortium Receiving a Mixed Waste

    OpenAIRE

    Fettig, James Drew

    1998-01-01

    The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent...

  6. Effect of swelling behavior of organoclays in styrene on flammability of polystyrene nanocomposites obtained through in situ incorporation

    International Nuclear Information System (INIS)

    Timochenco, Licinia; Sayer, Claudia; Machado, Ricardo A.F.; Araujo, Pedro H.H.

    2009-01-01

    In this work the effect of the interaction between organoclays and styrene on the flammability of polystyrene/clay nanocomposites obtained through in-situ incorporation was investigated. The reactions were carried out in bulk polymerization. The interaction between organoclays and styrene was inferred by swelling of the organoclay in styrene. The nanocomposites were characterized by X-ray diffraction and Transmission Electron Microscopy. The heat release rate was obtained by Cone Calorimeter and the nanocomposites were tested through UL94 horizontal burn test. Thermogravimetric analysis were also performed. Results showed that intercalated and partially exfoliated nanocomposites were obtained depending on the swelling behavior of the organoclay in styrene. It was also observed an increase of the higher decomposition temperature and an accentuated decrease on the peak of heat release of the nanocomposites when comparing to the virgin polymer. No remarkable effect between the swelling behavior of the organoclay in styrene and the flammability properties was observed. (author)

  7. Impact behaviour of acrylonitrile-butadiene-styrene after temperature and humidity load

    Directory of Open Access Journals (Sweden)

    Hylova Lenka

    2017-01-01

    Full Text Available This study deals with acrylonitrile-butadiene-styrene (ABS which was subjected the drop-weight test before and after temperature and humidity load. ABS is an engineering plastic and also an important engineering terpolymer, which has butadiene part uniformly distributed through the acrylonitrile-styrene matrix and is commonly used in production of automotive interior components. The injection moulded ABS samples were subjected the penetration test at fall height 100 J before and after temperature and humidity load and the results were subsequently evaluated and discussed. It was found out that ABS after temperature and humidity load has lower impact resistance.

  8. Synthesis by ATRP of triblock copolymers with densely grafted styrenic end blocks from a polyisobutylene macroinitiator

    DEFF Research Database (Denmark)

    Truelsen, Jens Høg; Kops, Jørgen; Pedersen, Walther Batsberg

    2000-01-01

    A macroinitiator was prepared from a triblock copolymer of polyisobutylene (PIB) with end blocks of poly(p-methylstyrene) (P(p-MeS)) by bromination to obtain initiating bromomethyl groups for atom transfer radical polymerization (ATRP). Controlled polymerization of styrene and p-acetoxystyrene yi......A macroinitiator was prepared from a triblock copolymer of polyisobutylene (PIB) with end blocks of poly(p-methylstyrene) (P(p-MeS)) by bromination to obtain initiating bromomethyl groups for atom transfer radical polymerization (ATRP). Controlled polymerization of styrene and p...

  9. Thermochemical data and additivity group values for ten species of o-xylene low-temperature oxidation mechanism.

    Science.gov (United States)

    Canneaux, Sébastien; Vandeputte, Romain; Hammaecher, Catherine; Louis, Florent; Ribaucour, Marc

    2012-01-12

    o-Xylene could be a good candidate to represent the family of aromatic hydrocarbons in a surrogate fuel. This study uses computational chemistry to calculate standard enthalpies of formation at 298 K, Δ(f)H°(298 K), standard entropies at 298 K, S°(298 K), and standard heat capacities C(p)°(T) over the temperature range 300 K to 1500 K for ten target species present in the low-temperature oxidation mechanism of o-xylene: o-xylene (1), 2-methylbenzyl radical (2), 2-methylbenzylperoxy radical (3), 2-methylbenzyl hydroperoxide (4), 2-(hydroperoxymethyl)benzyl radical (5), 2-(hydroperoxymethyl)benzaldehyde (6), 1-ethyl-2-methylbenzene (7), 2,3-dimethylphenol (8), 2-hydroxybenzaldehyde (9), and 3-hydroxybenzaldehyde (10). Δ(f)H°(298 K) values are weighted averages across the values calculated using five isodesmic reactions and five composite calculation methods: CBS-QB3, G3B3, G3MP2, G3, and G4. The uncertainty in Δ(f)H°(298 K) is also evaluated. S°(298 K) and C(p)°(T) values are calculated at B3LYP/6-311G(d,p) level of theory from molecular properties and statistical thermodynamics through evaluation of translational, rotational, vibrational, and electronic partition functions. S°(298 K) and C(p)°(300 K) values are evaluated using the rigid-rotor-harmonic-oscillator model. C(p)°(T) values at T ≥ 400 K are calculated by treating separately internal rotation contributions and translational, external rotational, vibrational, and electronic contributions. The thermochemical properties of six target species are used to develop six new additivity groups taking into account the interaction between two substituents in ortho (ORT/CH2OOH/ME, ORT/ET/ME, ORT/CHO/OH, ORT/CHO/CH2OOH) or meta (MET/CHO/OH) positions, and the interaction between three substituents (ME/ME/OH123) located one beside the other (positions numbered 1, 2, 3) for two- or three-substituted benzenic species. Two other additivity groups are also developed using the thermochemical properties of

  10. Improved assignments of the vibrational fundamental modes of ortho-, meta-, and para-xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection

    Science.gov (United States)

    Lindenmaier, Rodica; Scharko, Nicole K.; Tonkyn, Russell G.; Nguyen, Kiet T.; Williams, Stephen D.; Johnson, Timothy J.

    2017-12-01

    Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, high quality quantitative vapor-phase infrared spectra of all three isomers over the 6500 - 540 cm-1 range are reported. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C2v symmetry for ortho-xylene, and two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have Cs and C2 symmetry, and for para-xylene these conformers have C2v or C2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, an arbitrary choice to discuss the Cs conformer for meta-xylene and the C2v conformer for para-xylene is made. Integrated band intensities for all isomers are reported. Using the quantitative infrared data, the global warming potential values of each isomer are determined. Potential bands for atmospheric monitoring are also discussed.

  11. Activity of toluene-degrading Pseudomonas putida in the early growth phase of a biofilm for waste gas treatment

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Møller, S.; Molin, S.

    1997-01-01

    the increase of active biomass and polymers was linear. In order to investigate the toluene degradation, various toluene degraders from the multispecies biofilm were isolated, and a Pseudomonas putida was chosen as a representative of the toluene-degrading population. A specific rRNA oligonucleotide probe...... was used to follow the toluene-degrading P. putida in the multispecies biofilm in the filter by means of number and cellular rRNA content. P. putida appeared to detach from the biofilm during the first three days of growth, after which P. putida was found at a constant level of 10% of the active biomass...... in the biofilm. Based on the rRNA content, the in situ activity was estimated to be reduced to 20% of cells grown at maximum conditions in batch culture. The toluene degraded by P. putida was estimated to be a minor part (11%) of the overall toluene degradation. (C) 1997 John Wiley & Sons, Inc....

  12. Changes in markers of oxidative stress and membrane properties in synaptosomes from rats exposed prenatally to toluene

    DEFF Research Database (Denmark)

    Edelfors, Sven; Hass, Ulla; Hougaard, Karin S.

    2002-01-01

    for the experiments, Synaptosomes from rats exposed prenatally to toluene exhibited an increased level of oxidative stress when incubated with toluene in vitro compared to synaptosomes from unexposed offspring. Also the cell membrane was affected, as the calcium leakage was more increased from exposed synaptosomes......The present study was undertaken in order to investigate if toluene induced oxidative stress in brains from rats exposed prenatally to 1800 ppm toluene 6 hr/day at days 7-20 during the pregnancy. 35-42 days after birth the rats were killed and synaptosomal fractions were prepared...... than from unexposed. The membrane fluidity increased significantly when synaptosomes were incubated with toluene for 10 min. in vitro but the change in fluidity was identical in both groups of offspring. The results indicate that prenatal exposure to toluene induces long-lasting changes in oxidative...

  13. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via UV-induced graft polymerization of N-vinyl pyrrolidone.

    Science.gov (United States)

    Luan, Shifang; Zhao, Jie; Yang, Huawei; Shi, Hengchong; Jin, Jing; Li, Xiaomeng; Liu, Jingchuan; Wang, Jianwei; Yin, Jinghua; Stagnaro, Paola

    2012-05-01

    Poly(N-vinyl pyrrolidone) (PNVP) was covalently grafted onto the surface of biomedical poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer via a technique of UV-induced graft polymerization combined with plasma pre-treatment. The surface graft polymerization of N-vinyl pyrrolidone (NVP) was confirmed by ATR-FTIR and XPS. Effect of the parameters of graft polymerization, i.e., the initiator concentration, the UV irradiation time and the monomer concentration on the grafting density was investigated. The morphology and the wettability of the PNVP-modified surfaces were characterized by AFM and DSA, respectively. Protein adsorption and platelet adhesion were obviously suppressed after PNVP was grafted onto the SEBS substrates. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Improved biocompatibility of poly (styrene-b-(ethylene-co-butylene)-b-styrene) elastomer by a surface graft polymerization of hyaluronic acid.

    Science.gov (United States)

    Li, Xiaomeng; Luan, Shifang; Shi, Hengchong; Yang, Huawei; Song, Lingjie; Jin, Jing; Yin, Jinghua; Stagnaro, Paola

    2013-02-01

    Hyaluronic acid (HA) is an important component of extracellular matrix (ECM) in many tissues, providing a hemocompatible and supportive environment for cell growth. In this study, glycidyl methacrylate-hyaluronic acid (GMHA) was first synthesized and verified by proton nuclear magnetic resonance ((1)H NMR) spectroscopy. GMHA was then grafted to the surface of biomedical elastomer poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) via an UV-initiated polymerization, monitored by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The further improvement of biocompatibility of the GMHA-modified SEBS films was assessed by platelet adhesion experiments and in vitro response of murine osteoblastic cell line MC-3T3-E1 with the virgin SEBS surface as the reference. It showed that the surface modification with HA strongly resisted platelet adhesion whereas improved cell-substrate interactions. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Deactivation properties of a high-productive vanadia-titania catalyst for oxidation of o-xylene to phthalic anhydride

    Directory of Open Access Journals (Sweden)

    A. T. Georgieva

    2008-06-01

    Full Text Available The behavior of a high-productive V2O5-TiO2 (anatase supported O 4-28 catalyst for oxidation of o-xylene to phthalic anhydride was investigated in the first three years of its exploitation in industry. By using a suitable mathematical model, an identification problem was solved and activation profiles of the catalyst along a fixed bed located in the tubes of an industrial reactor were determined. Experimental temperature regimes and yields of the main and side products for different periods of the catalyst life were used. The proper technological regimes providing for a maximum yield according to the requirements of the catalyst producer company were defined.

  16. Chemogenetic Excitation of Accumbens-Projecting Infralimbic Cortical Neurons Blocks Toluene-Induced Conditioned Place Preference.

    Science.gov (United States)

    Wayman, Wesley N; Woodward, John J

    2018-02-07

    Abuse rates for inhalants among adolescents continue to be high, yet preclinical models for studying mechanisms underlying inhalant abuse remain limited. Our laboratory has previously shown that, in male rats, an acute binge-like exposure to toluene vapor that mimics human solvent abuse modifies the intrinsic excitability of mPFC pyramidal neurons projecting to the NAc. These changes showed region (infralimbic; IL vs prelimbic; PRL), layer (shallow; 2/3 vs deep; 5/6), target (core vs shell), and age (adolescent vs adult) dependent differences (Wayman and Woodward, 2017). To expand these findings using reward-based models that may better mimic human drug abuse, we used whole-cell electrophysiology and drug receptors exclusively activated by designer drugs to examine changes in neuronal function and behavior in rats showing a conditioned place preference (CPP) to toluene. Repeated pairings of adolescent rats to binge concentrations of toluene vapor previously shown to enhance dopamine release in reward-sensitive areas of the brain produced CPP that persisted for 7 but not 30 d. Toluene-induced CPP was associated with increased excitability of IL5/6 mPFC neurons projecting to the core of the NAc and reduced excitability of those projecting to the NAc shell. No changes in PRL-NAc-projecting neurons were found in toluene-CPP rats. Chemogenetic reversal of the toluene-induced decrease in IL5/6-NAc shell neurons blocked the expression of toluene-induced CPP while manipulating IL5/6-NAc core neuron activity had no effect. These data reveal that alterations in selective mPFC-NAc pathways are required for expression of toluene-induced CPP. SIGNIFICANCE STATEMENT Disturbed physiology of pyramidal neurons projecting from the mPFC to the NAc has been shown to have different roles in drug-seeking behaviors for a number of drugs (e.g., methamphetamine, cocaine, ecstasy, alcohol, heroin). Here, we report that rats repeatedly exposed to the volatile organic solvent toluene, a

  17. Evidence for acetyl coenzyme A and cinnamoyl coenzyme A in the anaerobic toluene mineralization pathway in Azoarcus tolulyticus Tol-4.

    OpenAIRE

    Chee-Sanford, J C; Frost, J W; Fries, M R; Zhou, J; Tiedje, J M

    1996-01-01

    A toluene-degrading denitrifier, Azoarcus tolulyticus Tol-4, was one of eight similar strains isolated from three petroleum-contaminated aquifer sediments. When the strain was grown anaerobically on toluene, 68% of the carbon from toluene was found as CO2 and 30% was found as biomass. Strain Tol-4 had a doubling time of 4.3 h, a Vmax of 50 micromol x min-1 x g of protein-1, and a cellular yield of 49.6 g x mol of toluene-1. Benzoate appeared to be an intermediate, since F-benzoates accumulate...

  18. A novel xylene-free deparaffinization method for the extraction of proteins from human derived formalin-fixed paraffin embedded (FFPE) archival tissue blocks.

    Science.gov (United States)

    Mansour, Anthony; Chatila, Rajaa; Bejjani, Noha; Dagher, Carole; Faour, Wissam H

    2014-01-01

    Protein detection methods in formalin-fixed paraffin embedded (FFPE) tissue blocks are widely used in research and clinical setting in order to diagnose or to confirm a diagnosis of various types of diseases. Therefore, multiple protein extraction methods from FFPE tissue sections have been developed in this regard. However, the yield and the quality of proteins extracted from FFPE tissues are significantly reduced in blocks stored for longer periods of time. Regardless the protein extraction method used, tissue sections must be first deparaffinized with xylene, and then washed in serial dilutions of ethanol in order to remove the toxic organic solvent "xylene" and rehydrate the tissue. The objective of this study was first to develop a method to deparaffinize FFPE blocks that excludes the use of toxic solvent "xylene". Second minimize the time required to perform the extraction. Here we describe a method where:•The entire paraffin embedded blocks are deparaffinized and rehydrated using only hot distilled water as a substitute for both xylene and ethanol•The entire procedure takes about 15 min•Deparaffinized blocks are immediately homogenized in lysis buffer, and the obtained lysate analyzed by Western blot. With this new modified technique, we were able to successfully detect actin and AKT proteins in lysates from blocks embedded in paraffin for up to 9 years.

  19. o-Xylene removal using one- and two-phase partitioning biotrickling filters: steady/transient-state performance and microbial community.

    Science.gov (United States)

    Wu, Chao; Xu, Peilun; Xu, Bailong; Li, Wei; Li, Sujing; Wang, Xiangqian

    2018-01-01

    In this study, one- and two-phase partitioning biotrickling filters (1P-BTF and 2P-BTF, respectively) inoculated with a pre-acclimated mixed culture were examined for the removal of hydrophobic and refractory o-xylene. A small fraction of silicone oil (5% v/v) was added as a non-aqueous phase. Due to the presence of silicone oil, the 2P-BTF exhibited superior performance and stability for o-xylene biodegradation at steady and transient operations. Higher macro-kinetic constants for o-xylene removal by the Michaelis-Menten model were obtained for the 2P-BTF with a saturation constant of 0.396 g m -3 and a maximum elimination capacity of 105.7 g m -3  h -1 . The enhancement of removal performance for the 2P-BTF was supported by dominant specialized microorganisms with o-xylene biodegradability. The diversity of microbial community was influenced by the presence of silicone oil. This study demonstrated that a BTF with 5% of silicone oil could be applied for the treatment of hydrophobic and refractory volatile organic compounds. It also provided valuable information for better understanding the relationship between microbial community and removal performance using two-phase partitioning bioreactors.

  20. DETERMINATION OF A BOUND MUSK XYLENE METABOLITE IN CARP HEMOGLOBIN AS A BIOMARKER OF EXPOSURE BY GAS CHROMATOGRAPHY MASS SPECTROMETRY USING SELECTED ION MONITORING

    Science.gov (United States)

    Musk xylene (MX) is widely used as a fragrance ingredient in commercial toiletries. Identification and quantification of a bound 4-amino-MX (AMX) metabolite was carried out by gas chromatography-mass spectrometry (GC/MS), with selected ion monitoring (SIM). Detection of AMX occur...

  1. Highly selective adsorption of p-xylene over other C-8 aromatic hydrocarbons by Co-CUK-1: a combined experimental and theoretical assessment

    NARCIS (Netherlands)

    Yoon, J.W.; Lee, J.S.; Piburn, G.W.; Cho, K.H.; Jeon, K.; Lim, H.; Kim, H.; Jun, C.; Humphrey, S.M.; Krishna, R.; Chang, J.

    2017-01-01

    High quality crystalline Co-CUK-1 can be synthesized rapidly and efficiently by a microwave-assisted method. The resulting microporous coordination material is a highly effective adsorbent for the separation of xylene isomers and ethylbenzene, as demonstrated here through sorption isotherm analysis,

  2. Sorption kinetics of toluene in humin under two different levels of relative humidity.

    Science.gov (United States)

    Shih, Yang-hsin; Wu, Shian-chee

    2002-01-01

    To identify any resistant fraction for desorption of toluene from humin and to quantify the sorption-desorption rates, the time courses of toluene sorption to compressed humin disks and to a thin humin film were investigated. The apparent diffusivity of toluene with humin disks ranges from 10(-8) to 10(-9) cm2/s and increases with temperature, based on the weight change of humin disks mounted on a microbalance and on the results simulated by use of a diffusion model. No detectable level of residual toluene was found after desorption, as revealed either by the gravimetric analysis or by the Fourier transform infrared (FTIR) spectrum obtained at either low or high humidity. The time scale for intrinsic vapor sorption without mass transfer hindrance is less than a few minutes with the thin film. All the results indicate that the sorption of toluene to humin is reversible and mainly diffusion controlled. This finding helps to better understand the sorption kinetics associated with humin and soil organic matter.

  3. PANI and Graphene/PANI Nanocomposite Films — Comparative Toluene Gas Sensing Behavior

    Directory of Open Access Journals (Sweden)

    Mitesh Parmar

    2013-12-01

    Full Text Available The present work discusses and compares the toluene sensing behavior of polyaniline (PANI and graphene/polyaniline nanocomposite (C-PANI films. The graphene–PANI ratio in the nanocomposite polymer film is optimized at 1:2. For this, N-methyl-2-pyrrolidone (NMP solvent is used to prepare PANI-NMP solution as well as graphene-PANI-NMP solution. The films are later annealed at 230 °C, characterized using scanning electron microscopy (SEM as well Fourier transform infrared spectroscopy (FTIR and tested for their sensing behavior towards toluene. The sensing behaviors of the films are analyzed at different temperatures (30, 50 and 100 °C for 100 ppm toluene in air. The nanocomposite C-PANI films have exhibited better overall toluene sensing behavior in terms of sensor response, response and recovery time as well as repeatability. Although the sensor response of PANI (12.6 at 30 °C, 38.4 at 100 °C is comparatively higher than that of C-PANI (8.4 at 30 °C, 35.5 at 100 °C, response and recovery time of PANI and C-PANI varies with operating temperature. C-PANI at 50 °C seems to have better toluene sensing behavior in terms of response time and recovery time.

  4. Toluene and benzene inhalation influences on ventricular arrhythmias in the rat.

    Science.gov (United States)

    Magos, G A; Lorenzana-Jiménez, M; Vidrio, H

    1990-01-01

    We have previously found that toluene did not share the capacity of benzene for increasing the arrhythmogenic action of epinephrine in the rat, but appeared to elicit the opposite effect. The present experiments were carried out to verify this observation in rats subjected to more severe ventricular arrhythmias. In animals previously inhaling either air, toluene or benzene and anesthetized with pentobarbital, arrhythmias were produced by coronary ligation or aconitine. In both models, toluene decreased and benzene increased the number of ectopic ventricular beats in the 30 min following induction of arrhythmia. Gas chromatographic measurement of toluene levels in the heart during and after inhalation revealed essentially constant concentrations at the time of arrhythmia evaluation, equivalent to approximately one-third the peak levels observed at the end of inhalation. Although the mechanism of the effect of toluene on arrhythmia could not be ascertained, nonspecific membrane stabilization or central serotonergic stimulation were considered as possible explanations. Since both mechanisms could be operant also in the case of benzene, the opposite effects of the solvents on arrhythmia could not be readily accounted for.

  5. Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

    Science.gov (United States)

    Hinks, Mallory L.; Montoya-Aguilera, Julia; Ellison, Lucas; Lin, Peng; Laskin, Alexander; Laskin, Julia; Shiraiwa, Manabu; Dabdub, Donald; Nizkorodov, Sergey A.

    2018-02-01

    The effect of relative humidity (RH) on the chemical composition of secondary organic aerosol (SOA) formed from low-NOx toluene oxidation in the absence of seed particles was investigated. SOA samples were prepared in an aerosol smog chamber at SOA generated at 75 % RH compared to SOA generated under dry conditions. In a separate set of experiments, the particle mass concentrations were measured with a scanning mobility particle sizer (SMPS) at RHs ranging from SOA. The volatility distributions of the SOA compounds, estimated from the distribution of molecular formulas using the molecular corridor approach, confirmed that low-NOx toluene SOA became more volatile on average under high-RH conditions. In contrast, the effect of RH on SOA mass loading was found to be much smaller for high-NOx toluene SOA. The observed increase in the oligomer fraction and particle mass loading under dry conditions were attributed to the enhancement of condensation reactions, which produce water and oligomers from smaller compounds in low-NOx toluene SOA. The reduction in the fraction of oligomeric compounds under humid conditions is predicted to partly counteract the previously observed enhancement in the toluene SOA yield driven by the aerosol liquid water chemistry in deliquesced inorganic seed particles.

  6. High formation of secondary organic aerosol from the photo-oxidation of toluene

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt

    2009-05-01

    Full Text Available Toluene and other aromatics have long been viewed as the dominant anthropogenic secondary organic aerosol (SOA precursors, but the SOA mass yields from toluene reported in previous studies vary widely. Experiments conducted in the Carnegie Mellon University environmental chamber to study SOA formation from the photo-oxidation of toluene show significantly larger SOA production than parameterizations employed in current air-quality models. Aerosol mass yields depend on experimental conditions: yields are higher under higher UV intensity, under low-NOx conditions and at lower temperatures. The extent of oxidation of the aerosol also varies with experimental conditions, consistent with ongoing, progressive photochemical aging of the toluene SOA. Measurements using a thermodenuder system suggest that the aerosol formed under high- and low-NOx conditions is semi-volatile. These results suggest that SOA formation from toluene depends strongly on ambient conditions. An approximate parameterization is proposed for use in air-quality models until a more thorough treatment accounting for the dynamic nature of this system becomes available.

  7. Toluene adsorption on VSbO4(110: a study of an electronic structure

    Directory of Open Access Journals (Sweden)

    Irigoyen B.L.

    2003-01-01

    Full Text Available The objective of this work is to electronically analyze toluene adsorption reactions on VSbO4(110. Thus, perpendicular and parallel toluene interactions on the different active sites of the oxide surface (O, Sb and V ions were studied. Adsorption energy was calculated using the ASED-MO theory, while the electronic analysis was performed with the YAEHMOP code. The electronic density of states (DOS of the VSbO4 cluster, modeled with a trirutile-type tetragonal supercell, resembles that of 3D solids with a rutile structure. However, due to the presence of vanadium, small peaks appear above the Fermi level. The DOS of toluene has several peaks resulting from the interaction of the aromatic ring with the methyl fragment, which changes when the adsorbate interacts with the oxide surface. The C-H bonds in the methyl fragment as well as the Cmethyl-Cphenyl bond weaken when some electronic density is removed. Also, hydrocarbon oxidation could weaken the p system of the aromatic ring. For toluene perpendicular adsorption (on the V site the calculations show a hybridization of those orbitals coming from the methyl fragment and the phenyl-methyl interaction energy region. After toluene parallel adsorption on Sb-V sites, the DOS shows an important broadening of some of the methyl and phenyl fragment orbitals. In addition, a study of the overlap population suggests that one of the H atoms of the methyl group can be abstracted with the participation of the Sb cation.

  8. Characterization and performance of a toluene-degrading biofilm developed on pumice stones

    Directory of Open Access Journals (Sweden)

    Sacceddu Pasquale

    2005-01-01

    Full Text Available Abstract Background Hydrocarbon-degrading biofilms in the treatment of contaminated groundwaters have received increasing attention due to the role played in the so-called "biobarriers". These are bioremediation systems in which a microbial consortium adherent to a solid support is placed across the flow of a contaminated plume, thus promoting biodegradation of the pollutant. Results A microbial consortium adherent to pumice granules (biofilm developed from a toluene-enriched microflora in a mini-scale system, following continuous supply of a mineral medium containing toluene, over a 12-month period. Observation by scanning electron microscopy, together with quantification of the biomass attached to pumice, evidenced the presence of abundant exopolymeric material surrounding the cells in the biofilm. Toluene removal monitored during 12-month operation, reached 99%. Identification of the species, based on comparative 16S ribosomal DNA (rDNA sequence analysis, revealed that Rhodococcus erythropolis and Pseudomonas marginalis were the predominant bacterial species in the microbial consortium. Conclusion A structurally complex toluene-degrading biofilm, mainly formed by Rhodococcus erythropolis and Pseudomonas marginalis, developed on pumice granules, in a mini-scale apparatus continuously fed with toluene.

  9. Removal of gaseous toluene and submicron aerosol particles using a dielectric barrier discharge reactor

    International Nuclear Information System (INIS)

    Byeon, Jeong Hoon; Park, Jae Hong; Jo, Yoon Shin; Yoon, Ki Young; Hwang, Jungho

    2010-01-01

    A lab-scale dielectric barrier discharge (DBD) reactor was fabricated, and gaseous and particulate contaminant removal tests were carried out under a range of DBD reactor operating conditions: applied voltage (5.0-8.5 kV), frequency (60-1000 Hz), upstream toluene concentration (50-200 ppm) and gas flow rate (1-5 L min -1 or 0.48-0.096 s of gas residence time). The results suggested that the toluene removal efficiency (at 1 L min -1 , 100 ppm) increased (up to ∼46%) either with increasing voltage (at 1000 Hz) or frequency (at 8.5 kV). The overall particle collection efficiency (at 1 L min -1 ) improved (up to ∼60%) with increasing voltage (at 1000 Hz) whereas the penetration of the particles increased (up to ∼40%) with increasing frequency (at 8.5 kV). The toluene removal efficiency (at 8.5 kV, 1000 Hz, 100 ppm) decreased (down to ∼29%) with increasing gas flow rate while the particle collection efficiency decreased slightly (maintaining ∼60%) regardless of the flow rate. In addition, the toluene removal efficiency (down to ∼41%) and carbon dioxide selectivity (down to ∼43%) decreased with increasing upstream toluene concentration (at 5 kV, 1000 Hz, 1 L min -1 ).

  10. Structural and energetical studies of the adsorption of para and meta-isomers of xylene on pre-hydrated zeolite BaX. Characterization by neutron diffraction and temperature programmed desorption; Etude structurale et energetique de l'adsorption des isomeres para- et meta- du xylene dans la zeolithe BaX prehydratee. Caracterisation par diffraction des neutrons et thermodesorption programmee

    Energy Technology Data Exchange (ETDEWEB)

    Pichon, Ch.

    1999-10-19

    The separation of p-xylene from C{sub 8} aromatics is performed industrially by selective adsorption on zeolitic materials. FAU-type zeolites are currently used for this separation and especially the partially hydrated BaX. The aim of this work is to characterize from a structural (by low temperature neutron powder diffraction) and an energetical (by temperature programmed desorption) point of view, the adsorption of para- and meta- isomers of xylene, for different fillings, as pure substances as well as mixtures, on pre-hydrated zeolite BaX. The influence of the water pre-adsorption on xylene adsorption selectivity is carefully discussed. The crystalline structure of the zeolite BaX (framework and compensation of charge cations) and of the adsorbed phase (water, p- and m-xylene molecules) are completely characterized by neutron diffraction. The location and the distribution of water and xylene molecules on their adsorption sites is especially followed as a function of the filling of the zeolite and of the composition of the adsorbed phase. Microscopic measurements were correlated to the energetical analysis (at a macroscopic level) in order to obtain a consistent description of adsorption phenomenon and to propose a possible origin for adsorption selectivity.

  11. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Science.gov (United States)

    2010-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene oxide...

  12. Expanding Upon Styrene Biosynthesis to Engineer a Novel Route to 2-Phenylethanol.

    Science.gov (United States)

    Machas, Michael S; McKenna, Rebekah; Nielsen, David R

    2017-10-01

    2-Phenylethanol (2PE) is a key molecule used in the fragrance and food industries, as well as a potential biofuel. In contrast to its extraction from plant biomass and/or more common chemical synthesis, microbial 2PE production has been demonstrated via both native and heterologous expression of the yeast Ehrlich pathway. Here, a novel alternative to this established pathway is systematically engineered in Escherichia coli and evaluated as a more robust and efficient route. This novel pathway is constructed via the modular extension of a previously engineered styrene biosynthesis pathway, proceeding from endogenous l-phenylalanine in five steps and involving four heterologous enzymes. This "styrene-derived" pathway boasts nearly a 10-fold greater thermodynamic driving force than the Ehrlich pathway, and enables reduced accumulation of acetate byproduct. When directly compared using a host strain engineered for l-phenylalanine over-production, preservation of phosphoenolpyruvate, and reduced formation of byproduct 2-phenylacetic acid, final 2PE titers via the styrene-derived and Ehrlich pathways reached 1817 and 1164 mg L -1 , respectively, at yields of 60.6 and 38.8 mg g -1 . Following optimization of induction timing and initial glucose loading, 2PE titers by the styrene-derived pathway approached 2 g L -1 - nearly a two-fold twofold increase over prior reports for 2PE production by E. coli employing the Ehrlich pathway. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Biosorption of styrene from synthetic wastewater by sugar cane waste(Bagass

    Directory of Open Access Journals (Sweden)

    Mehdi Hassanzadeh

    2015-04-01

    Full Text Available In this work, styrene removal from wastewater by using sugarcane waste (bagasse as an adsorbent was studied. Equilibrium isotherms and kinetics were determined; the effects of bagasse particle size and concentration, solutions pH, and temperature on the biosorption of styrene were studied in batch experiments. Adsorption equilibrium data was successfully fitted to Langmuir isotherms (R2=0.986 and Freundlich isotherms (R2=0.96. Also, the kinetics of biosorption was fitted to pseudo-second order equations (K2=0.00146 g mg-1 min-1, qe=24.5 mg g-1 for particle size range of 88-105 μm. According to the obtained results, an empirical equation was presented that could be used to calculate the percentage of styrene adsorption. The results showed that an increase in temperature caused a decrease in styrene removal. Moreover, maximum uptake was observed with NaOH-treated bagasse. It was found that an increase in average particle size decreased the biosorption rate. According to the calculated heat of adsorption, this sorption can be classified as a chemical biosorption. The optimum uptake was determined to be 88% at a pH equal to 12.1, a temperature of 35 oC, a particle size of 420-500 μm, and a bagasse concentration of 1 g L-1.

  14. The styrene-maleic acid copolymer: : a versatile tool in membrane research

    NARCIS (Netherlands)

    Dörr, Jonas M; Scheidelaar, Stefan; Koorengevel, Martijn C; Dominguez Pardo, Juan; Schäfer, Marre; van Walree, Cornelis A; Killian, J Antoinette

    A new and promising tool in membrane research is the detergent-free solubilization of membrane proteins by styrene-maleic acid copolymers (SMAs). These amphipathic molecules are able to solubilize lipid bilayers in the form of nanodiscs that are bounded by the polymer. Thus, membrane proteins can be

  15. DNA repair and cyclin D1 polymorphisms and styrene-induced genotoxicity and immunotoxicity

    Czech Academy of Sciences Publication Activity Database

    Kuricová, Miroslava; Naccarati, Alessio; Kumar, R.; Koskinen, M.; Sanyal, S.; Dušinská, M.; Tulinská, J.; Vodičková, Ludmila; Lisková, A.; Jahnová, E.; Fuortes, L.; Haufroid, V.; Hemminki, K.; Vodička, Pavel

    2005-01-01

    Roč. 207, - (2005), S302-S309 ISSN 0041-008X R&D Projects: GA ČR GA310/03/0437 Institutional research plan: CEZ:AV0Z5039906 Keywords : styrene genotoxicity * immunotoxicity Subject RIV: FM - Hygiene Impact factor: 3.148, year: 2005

  16. EVALUATION OF THE POLYAD FB AIR PURIFICATION AND SOLVENT RECOVERY PROCESS FOR STYRENE REMOVAL

    Science.gov (United States)

    The report gives results of a study evaluating the Polyad fluidized-bed (FB) process for controlling styrene emissions at a representative fiberglass shower stall and bath tub manufacturing plan*t. he process was evaluated using a transport able unit supplied by Weatherly, Inc., ...

  17. Optimisation of the biocatalytic resolution of styrene oxide by whole cells of Rhodotorula glutinis

    CSIR Research Space (South Africa)

    Yeates, CA

    2007-01-01

    Full Text Available biocatalytic hydrolysis of styrene oxide by Rhodotorula glutinis UOFS Y-0653 through the use of whole cells was explored. It was found that a pH of 7.2, temperature of 45 °C and an initial substrate concentration of 50 mM led to maximum enzymatic activity...

  18. Particle reinforced composites from acrylamide modified blend of styrene-butadiene and natural rubber

    Science.gov (United States)

    Blends of styrene-butadiene rubber and natural rubber that provide balanced properties were modified with acrylamide and reinforced with soy protein particles. The rubber composites show improved mechanical properties. Both modified rubber and composites showed a faster curing rate. The crosslinking...

  19. The isotope effect in the thermodynamic parameters of polymerization of styrene

    International Nuclear Information System (INIS)

    Lebedev, B.V.; Kirillin, A.I.; Kozyreva, N.M.; Lebedev, N.K.; Smirnova, N.N.

    1985-01-01

    This paper studies the effect of substitution of hydrogen by deuterium on the thermodynamic criteria of polymerization processes. The isotope effects in the enthalpy, entropy, and Gibbs energy of the polymerization of styrene are studied by the methods of adiabatic and isothermal calorimetry. The heat capacity of polystyrenes and polydeuterostyrenes are shown

  20. Biobased, thermoreversibly crosslinked polyesters : A styrene-free alternative to currently employed resins

    NARCIS (Netherlands)

    Beljaars, Martijn

    2017-01-01

    Polyester resins are often used due to their superior chemical and mechanical properties. However, most commercial resins contain high amounts of the toxic chemical styrene. This thesis describes the search for a human-friendly alternative to polyester resins. In this work, mostly biobased (obtained