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Sample records for toluene ethyl benzene

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

    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.)

  2. 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

    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.)

  3. Enthalpy of mixing and heat of vaporization of ethyl acetate with benzene and toluene at 298.15 k and 308.15 k

    K. L. Shivabasappa

    2008-03-01

    Full Text Available The present work was carried out in two phases. First, enthalpy of mixing was measured and then the heat of vaporization for the same mixtures was obtained. The data are useful in the design of separation equipments. From the various designs available for the experimental determination of enthalpy of mixing, and heat of vaporization, the apparatus was selected, modified and constructed. The apparatus of enthalpy of mixing was tested with a known system Benzene - i-Butyl Alcohol and the data obtained was in very good agreement with literature values. Experiments were then conducted for mixtures of Ethyl Acetate with Benzene and Toluene. The experimental data was fitted to the standard correlations and the constants were evaluated. Heat of vaporization data were obtained from a static apparatus and tested for accuracy by conducting experiments with a known system Benzene - n-Hexane and the data obtained were found to be in agreement with literature values. Experiments were then conducted to measure heat of vaporization for the mixtures of Ethyl Acetate with Benzene and Toluene. Using experimental data of enthalpy of mixing from the first phase, and heat capacity data, the heat of vaporization were calculated.

  4. Diaquabis(L-phenylalaninato)nickel(II) encapsulated in zeolite: an efficient heterogeneous catalyst system for the oxidation of cyclohexene, toluene and ethyl benzene

    Massomeh, Ghorbanloo; Somayeh, Ghamari; Nahid, Shahbakhsh; Seik Weng, Ng.

    2014-11-01

    Full Text Available L-Fenilalanina reage com zelita Y submetida a uma troca inica com nquel(II) para formar diaquabis(L-fenilalaninato)nquel(II), o qual encapsulado nos poros da zelita. Nesta forma encapsulada, o complexo de nquel funciona como um catalisador eficiente quando ciclo-hexeno, tolueno e etilbenzeno [...] so oxidados por perxido de hidrognio na presena de bicarbonato de sdio como cocatalisador. O catalisador foi facilmente recuperado da mistura de reao e foi reutilizado por trs vezes sem perda observvel de atividade. O catalisador heterogneo apresentou atividade e seletividade significativamente mais altas quando comparado com o complexo diaquabis(L-fenilalaninato)nquel(II). Abstract in english L-Phenylalanine reacts with nickel-exchanged zeolite Y to form diaquabis(L-phenylalaninato)nickel(II), which is encapsulated in the pores of the zeolite. In this zeolite-encapsulated form, the nickel derivative functions as an efficient catalyst when cyclohexene, toluene and ethyl benzene are oxidiz [...] ed by hydrogen peroxide in the presence of sodium bicarbonate (as co-catalyst). The catalyst was readily recovered from the reaction mixture, and it could be re-used for other three runs without noticeable loss of activity. The heterogeneous catalyst exhibited significantly higher activity and selectivity compared with diaquabis(L-phenylalaninato)nickel(II) itself.

  5. Excited state of protonated benzene and toluene

    We present photo-fragmentation electronic spectra of the simplest protonated aromatic molecules, protonated benzene and toluene, recorded under medium resolution conditions and compared with the photo-fragmentation spectrum of protonated pyridine. Despite the resolution and cold temperature achieved in the experiment, the electronic spectra of protonated benzene and toluene are structure-less, thus intrinsically broadened. This is in agreement with the large geometrical changes and the fast dynamic toward internal conversion predicted by ab initio calculations for protonated benzene [Rode et al., J. Phys. Chem. A 113, 5865–5873 (2009)

  6. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    Emmerling, Uwe; Rasmussen, Peter

    1998-01-01

    Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...... a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means...

  7. Metabolism of Benzene, Toluene, and Xylene Hydrocarbons in Soil

    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...

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

    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)

  9. Diffusive Motions in Benzene and Toluene Studied with Slow Neutrons

    The viscosity of benzene is described by the Arrhenius equation ή = const. exp (E/kBT), where E is the activation energy for viscous flow. The viscosity of toluene, however, follows this law only in the higher temperature region of its liquid range, i.e. above the Arrhenius temperature TA. In the whole normal liquid range the benzene molecule is supposed to be able to rotate many times about at least two symmetry axes between translational jumps. Davies and Matheson suggest that the onset of non-Arrhenius viscosity behaviour in toluene occurs at that temperature at which rotation about two axes becomes restricted, while rotation about the third remains free. Inelastic scattering experiments of slow neutrons have been performed on the two substances using a time-of-flight spectrometer for cold neutrons with an energy resolution of 12 %. The quasi-elastic scattering has been studied for small momentum transfer as a function of temperature. Diffusion coefficients have been determined assuming a Lorentzian cross-section. The temperature dependence of the diffusion coefficient for benzene follows an exponential law, but the coefficient is a few times larger than the macroscopic coefficient, showing that a large amount of rotational diffusion exists. For toluene there is a change in the temperature dependence of the coefficient at about TA. This is taken as an indication of a change in the number of degrees of rotational freedom of the toluene molecule around TA. The methyl group in toluene has a low barrier to rotation (≲500 cal/mole). Therefore the hindered rotation levels of the methyl group as well as molecular rotation will contribute significantly to the inelastic scattering spectrum which overlaps the quasi-elastic peak. Th e inelastic component is subtracted by extrapolation but the possible contribution of the CH3 rotation to the quasi-elastic peak itself is neglected. (author)

  10. Comparison of measurement methods for benzene and toluene

    Wideqvist, U.; Vesely, V.; Johansson, C.; Potter, A.; Brorstrm-Lundn, E.; Sjberg, K.; Jonsson, T.

    Diffusive sampling and active (pumped) sampling (tubes filled with Tenax TA or Carbopack B) were compared with an automatic BTX instrument (Chrompack, GC/FID) for measurements of benzene and toluene. The measurements were made during differing pollution levels and different weather conditions at a roof-top site and in a densely trafficked street canyon in Stockholm, Sweden. The BTX instrument was used as the reference method for comparison with the other methods. Considering all data the Perkin-Elmer diffusive samplers, containing Tenax TA and assuming a constant uptake rate of 0.406 cm3 min-1, showed about 30% higher benzene values compared to the BTX instrument. This discrepancy may be explained by a dose-dependent uptake rate with higher uptake rates at lower dose as suggested by laboratory experiments presented in the literature. After correction by applying the relationship between uptake rate and dose as suggested by Roche et al. (Atmos. Environ. 33 (1999) 1905), the two methods agreed almost perfectly. For toluene there was much better agreement between the two methods. No sign of a dose-dependent uptake could be seen. The mean concentrations and 95% confidence intervals of all toluene measurements (67 values) were (10.801.6) ?g m -3 for diffusive sampling and (11.31.6) ?g m -3 for the BTX instrument, respectively. The overall ratio between the concentrations obtained using diffusive sampling and the BTX instrument was 0.910.07 (95% confidence interval). Tenax TA was found to be equal to Carbopack B for measuring benzene and toluene in this concentration range, although it has been proposed not to be optimal for benzene. There was also good agreement between the active samplers and the BTX instrument.

  11. Anti-benzene compounds. Conversion of benzene to toluene by methyl donors, in man.

    Braier, L

    1977-01-01

    The level of benzene in blood can be efficiently reduced, an its noxious effect neutralized, by the concurrent administration of either of two groups of organic compounds: 1) methyl donors such as choline and betaine; and, 2) cysteine-HCL. Methionine acts as a precursor of cysteine in the body as uell as a methyl donor like choline and betaine. The appearance of toluene in blood was demonstrated after the sequential ingestion of choline plus betaine, benzene. The results are discussed in relation to clinical application in workers chronically exposed to benzene. PMID:594433

  12. Competitive Nitration of Benzene-Fluorobenzene and Benzene-Toluene Mixtures: Orientation and Reactivity Studies Using HPLC

    Blankespoor, Ronald L.; Hogendoorn, Stephanie; Pearson, Andrea

    2007-01-01

    The reactivity and orientation effects of a substituent are analyzed by using HPLC to determine the competitive nitration of the benzene-toluene and benzene-fluorobenzene mixtures. The results have shown that HPLC is an excellent instrumental method to use in analyzing these mixtures.

  13. Benzene, toluene and C 2-benzene emissions of 4-stroke motorbikes: Benefits and risks of the current TWC technology

    Saxer, Christian J.; Forss, Anna-Maria; Rüdy, Claudio; Heeb, Norbert V.

    Chemical ionization mass spectrometry has been applied to determine benzene, toluene and C 2-benzene emission rates of 4-stroke motorbikes. Extra emissions and duration of the cold start were deduced from the legislative urban driving cycle. The Common Artemis driving cycle was investigated to study the emission characteristics at transient driving from 0 to 135 km h -1. In addition, the benefits and risks of the currently available 3-way catalyst technology (TWC) are explored. Benzene, toluene and C 2-benzene cold start emissions of 230-290, 920-980 and 950-1270 mg start -1 were obtained for the TWC motorbikes, exceeding those without catalyst by more than a factor of 3. At hot engine/catalyst, benzene, toluene and C 2-benzene emission factors in the range of 10-140, 10-160 and 10-170 mg km -1 were found for the TWC motorbikes. Without catalyst, the corresponding emission factors were higher, varying from 40 to 260, 100 to 500 and 110 to 480 mg km -1, respectively. A comparison with the latest passenger car technology, with reported aromatic hydrocarbon (HC) emission factors of 0.2-3.0 mg km -1, revealed that the investigated 4-stroke motorbikes, indeed, are an important source of air pollution. Furthermore, cold start duration, driving distance under cold start influence and velocity dependence of aromatic HC emissions were deduced from time-resolved data. In addition, variations of aromatic HC mixing ratios were studied. Narrow and unimodal distributions of, e.g. benzene/C 2-benzene mixing ratios with median values of 0.46-0.73 were found for all motorbikes but one. This motorcycle, equipped with a TWC, showed a broad and bimodal distribution with a median mixing ratio of 1.47. Catalyst-induced formation of benzene from alkylbenzenes is the assumed process, leading to increased benzene/alkylbenzene mixing ratios.

  14. Kinetic modeling of benzene and toluene decomposition in air and in flue gas under electron beam irradiation

    Computer simulations of benzene and toluene decomposition in air (79% N2+21% O2) and in flue gas (87% N2+10% O2+3% H2O+160 ppm SO2+80 ppm NO) under electron beam (EB) irradiation were carried out using computer code KINETIC and GEAR method. 285 reactions involving 73 species and 294 reactions involving 78 species were considered for simulation of benzene and toluene decomposition, respectively. Calculation results of benzene and toluene decomposition in air under electron beam agree well with the published experimental results. ·OH radicals play a main role in benzene or toluene decomposition. - Highlights: ► Benzene/toluene decompositions under electron beam irradiation were simulated. ► Computer code KINETIC and GEAR method were used. ► By-products of benzene/toluene decomposition under EB irradiation were predicted.

  15. Biodegradation of methane, benzene, and toluene by a consortium MBT14 enriched from a landfill cover soil.

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2013-01-01

    In this study, landfill cover soil was used as an inoculum source to enrich a methane, benzene, and toluene-degrading consortium MBT14. Under a single substrate, the maximum degradation rates of methane, benzene and toluene were 1.96, 0.15, and 0.77 mmole g-DCW(-1) h(-1), respectively. Although the coexistence of benzene and toluene inhibited the methane degradation rates, the consortium was able to simultaneously degrade methane, benzene and toluene. Methane had an insignificant effect on benzene or toluene degradation. Based on 16S rDNA sequencing analysis, Cupriavidus spp. are dominant in the consortium MBT14. The combined results of this study indicate that the consortium MBT 14 is a promising bioresource for removing CH(4), benzene, and toluene from a variety of environments. PMID:23245302

  16. Incorporation of oxygen from water into toluene and benzene during anaerobic fermentative transformation

    Toluene and benzene were anaerobically transformed and eventually mineralized in mixed methanogenic cultures. However, the source of oxygen for the initial oxidation step had been unknown, owing to the presence of both methanol and water. No exogenous electron acceptors other than carbon dioxide, toluene, and benzene were present in the defined mineral medium. Through the use of 18O-labeled water, the oxygen incorporated into the monoaromatic compounds was shown to come from water. The cresol from the toluene and the phenol from the benzene contain up to 8% 18O label after incubation in 9% 18O-labeled medium. Gas chromatography-mass spectrometry was used to detect the 18O-labeled aromatic metabolites

  17. Solubilities of Toluene, Benzene and TCE in High-Biomass Systems

    Barton, John W. [Battelle Eastern Science & Technology Center; Vodraska, Christopher D [ORNL; Flanary, Sandie A. [Oak Ridge National Laboratory (ORNL); Davison, Brian H [ORNL

    2008-01-01

    We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g/mL. The solubility limit increased from 20 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20 mM. For TCE, the solubility increased from 8 mM to more than 1000 mM. Solubility for TCE was most heavily impacted by biomass levels, changing by two orders of magnitude.

  18. Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

    Sekiguchi, H; Ando, M; Kojima, H [Department of Chemical Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2005-06-07

    The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C{sub 4}-compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C{sub 4}-compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring.

  19. Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

    The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C4-compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C4-compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring

  20. Biomonitoring of benzene and toluene in human blood by headspace-solid-phase microextraction

    Schimming, E.; Levsen, K. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung (ITA), Hannover (Germany); Koehme, C.; Schuermann, W. [Medizinische Hochschule Hannover (Germany). Abt. fuer Pneumologie

    1999-01-01

    A simple and rapid method for the determination of benzene and toluene in whole blood by headspace-solid-phase microextraction (HS-SPME) is described. Using SPME fibres coated with 65 {mu}m carboxene/polydimethylsiloxane, limits of quantification (LOQ) of 5 ng/L for benzene and 25 ng/L for toluene are achieved. As a result of its large linear range (i.e. 5-5000 ng/L for benzene) the method is suitable for biomonitoring of both occupationally and environmentally exposed people. The reproducibility of the determination of benzene is {<=} 8%. An interlaboratory comparison demonstrated that the method proposed here compares favorably with existing methods (dynamic headspace, purge and trap). (orig.) With 2 figs., 2 tabs., 10 refs.

  1. Photoacoustic spectroscopy-based detector for measuring benzene and toluene concentration in gas and liquid samples

    Here we present a novel instrument for on-line, automatic measurement of benzene and toluene concentration in gas and liquid samples produced in the natural gas industry. Operation of the instrument is based on the collection of analytes on an adsorbent, separation using a chromatographic column and detection by near-infrared diode laser-based photoacoustic spectroscopy. Sample handling, measurement and data evaluation are carried out fully automatically, using an integrated, programmable electronic unit. The instrument was calibrated in the laboratory for natural gas, nitrogen and liquid glycol samples, and tested under field conditions at a natural gas dehydration unit of the MOL Hungarian Oil and Gas Company. Minimum detectable concentrations (3σm−1) were found to be 2.5 µg l−1 for benzene and 4 µg l−1 for toluene in gas samples, while 1.5 mg l−1 for benzene and 3 mg l−1 for toluene in liquid samples, which is suitable for measuring benzene and toluene concentration in natural gas and glycol samples occurring at natural gas dehydration plants

  2. Summertime measurements of benzene and toluene in Athens using a differential optical absorption spectroscopy system.

    Petrakis, Michael; Psiloglou, Basil; Kassomenos, Pavlos A; Cartalis, Costas

    2003-09-01

    In this paper, measurements of benzene, toluene, p,m-xylene, ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2) made using the differential optical absorption spectroscopy (DOAS) technique during a 4-month period of summer 2000 (June-September) in Athens, Greece, are presented. An assessment of benzene mean value concentrations during this 4-month period exceeded 10 microg/m3, which is 2 times greater than the average yearly limit proposed by European authorities. Toluene measurements present mean values of approximately 33 microg/m3. Benzene and especially toluene measurements are highly correlated with NO2 and anticorrelated with O3. High values of benzene, NO2, and toluene are also correlated with winds from the southeast section, an area of industrial activity where emissions of volatile organic compounds (VOCs) have been recorded in previous studies. O3 is correlated with winds from the south-southwest section affected by the sea breeze circulation. Diurnal variations of O3, NO2, and SO2 concentrations are compatible with measurements from the stations of the Ministry of Environment's network. Outliers are combined with weak winds from the south-southwest. As far as p,m-xylene measurements are concerned, there is a poor correlation between gas chromatography (GC) and DOAS Opsis measurements, also observed in previous relevant campaigns and eventually a criticism in the use of the DOAS Opsis model for the measurement of p,m-xylene. PMID:13678363

  3. Photodissociation spectroscopy of (benzene-toluene)+. Charge delocalization in the hetero-dimer ion

    The electronic spectrum of the benzene-toluene hetero-dimer ion is measured in the 380-1400 nm region. The spectrum shows intense bands around 1175 and 670 nm and a weaker band around 920 nm, which correspond to charge resonance (CR) bands of homo-dimer ions. The observation indicates that the positive charge stays on the benzene part in some probability, although the ionization potential of benzene is 0.4162 eV higher than that of toluene. A local excitation (LE) band is observed around 420 nm, where a πrelata of a relationπ transition is locally excited in the charged benzene or toluene molecule. On the basis of the positions of the CR-like bands, as well as the intensity of the LE band relative to that of homo-dimer ions, the probability of finding the charge on the benzene molecule is analyzed to be approximately 36%. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  4. Nucleotide sequence analysis of genes encoding a toluene/benzene-2-monooxygenase from Pseudomonas sp. strain JS150.

    G. R. Johnson; Olsen, R H

    1995-01-01

    It was previously shown by others that Pseudomonas sp. strain JS150 metabolizes benzene and alkyl- and chloro-substituted benzenes by using dioxygenase-initiated pathways coupled with multiple downstream metabolic pathways to accommodate catechol metabolism. By cloning genes encoding benzene-degradative enzymes, we found that strain JS150 also carries genes for a toluene/benzene-2-monooxygenase. The gene cluster encoding a 2-monooxygenase and its cognate regulator was cloned from a plasmid ca...

  5. Irradiation with benzene, toluene and phenol electron beams in aqueous solution

    It is described a methodology for waste water treatment which is simulated doing a benzene-toluene-phenol mixture in aqueous solution. Three different concentrations of them ones were used which were irradiated with electron beams coming from a Pelletron Accelerator carrying out the degradation effect of these compounds in CO2 and H2O. By mean of gas chromatography the analytical determinations were realized finding that in lower concentration of benzene and toluene performances of degradation higher than 95 % were obtained, but higher concentrations (100 ppm) the performance diminishes at 89 %, while for phenol in higher concentrations its degradation is over 60 % and in lower concentrations the degradation is under 80 %. The results are obtained with a constant irradiation time of 12 seconds and neutral pH. (Author

  6. Low temperature oxidation of benzene and toluene in mixture with n-decane

    Herbinet, Olivier; Husson, Benoit; Ferrari, Maude; Glaude, Pierre-Alexandre; Battin-Leclerc, Frdrique

    2011-01-01

    The oxidation of two blends, benzene/n-decane and toluene/n-decane, was studied in a jet-stirred reactor with gas chromatography analysis (temperatures from 500 to 1100 K, atmospheric pressure, stoichiometric mixtures). The studied hydrocarbon mixtures contained 75% of aromatics in order to highlight the chemistry of the low-temperature oxidation of these two aromatic compounds which have a very low reactivity compared to large alkanes. The difference of behavior between the two aromatic reac...

  7. Integrated Gas Sensing System of SWCNT and Cellulose Polymer Concentrator for Benzene, Toluene, and Xylenes

    Jisun Im; Elizabeth S. Sterner; Swager, Timothy M.

    2016-01-01

    An integrated cellulose polymer concentrator/single-walled carbon nanotube (SWCNT) sensing system is demonstrated to detect benzene, toluene, and xylenes (BTX) vapors. The sensing system consists of functionalized cellulose as a selective concentrator disposed directly on top of a conductive SWCNT sensing layer. Functionalized cellulose concentrator (top layer) selectively adsorbs the target analyte and delivers the concentrated analyte as near as possible to the SWCNT sensing layer (bottom l...

  8. Radiolysis ob benzene, toluene and phenol aqueous solutions utilizing high energy electron beam

    In a search for solutions to environmental pollution problems, radiolysis has proved to be an innovative technique for the removal of organic chemical pollutants in aqueous solution. Radiolysis has shown many advantages over many other techniques, as highly reactive species formed in water by ionizing radiation oxidize organic pollutants breaking down organic molecules to final simple products by oxidation to carbon dioxide and water in a complete oxidation. Our work consisted in doing some experiments in radiolysis with simulated polluted water to help us understand this technique and also develop, in a near future, a project for large scale water treatment. Our project includes the application of a Pelletron type Mexican made Electron Accelerator, which will affirm its capability and usefulness in performing investigation in this field of study. Experiments consisted in treating benzene, toluene and phenol aqueous solutions with an Electron Beam (0.48-0.55 MeV; 24 μA). Two concentrations were used for each compound: 5 and 20 ppm (mg/l) for benzene and toluene; 10 and 50 ppm for phenol. Solutions were prepared with pure, mineral free water and two different p H (5.9), in order to study the effect of concentration and p H on removal efficiency, but avoiding the interference of radical scavengers. Results obtained coincide with the ones reported by Cooper, Nickelsen and Kurucz; highly efficient removal was achieved for benzene (>99.8%), toluene (>98.0%) and phenol (>88%). There was no visible important effect of p H on radiolysis efficiency for benzene nor toluene, phenol however, showed lower removal efficiency in acidic conditions. Concentration of aqueous solutions, nevertheless, did show an important effect at low doses for phenol. Results obtained reveal the importance of this technique in water pollution control and water remedial as expressed by Cooper, Nickelsen and Kurucz, who have studied radiolysis of organic compounds and apply this technique in water site remedial with a mobile Electron Beam facility. (Author)

  9. Chemical kinetic modeling of benzene and toluene oxidation behind shock waves

    Mclain, A. G.; Jachimowski, C. J.; Wilson, C. H.

    1979-01-01

    The oxidation of stoichiometric mixtures of benzene and toluene behind incident shock waves was studied for a temperature range from 1700 to 2800 K and a pressure range from 1.1 to 1.7 atm. The concentration of CO and CO2 produced were measured as well as the product of the oxygen atom and carbon monoxide concentrations. Comparisons between the benzene experimental data and results calculated by use of a reaction mechanism published in the open literature were carried out. With some additional reactions and changes in rate constants to reflect the pressure-temperature range of the experimental data, a good agreement was achieved between computed and experimental results. A reaction mechanism was developed for toluene oxidation based on analogous rate steps from the benzene mechanism. Measurements of NOx levels in an actual flame device, a jet-stirred combustor, were reproduced successfully by use of the reaction mechanism developed from the shock-tube experiments on toluene. These experimental measurements of NOx levels were reproduced from a computer simulation of a jet-stirred combustor.

  10. Determination of Benzene, Toluene, and Xylene by means of an ion mobility spectrometer device using photoionization

    Leonhardt, J. W.; Bensch, H.; Berger, D.; Nolting, M.; Baumbach, J. I.

    1995-01-01

    The continuous monitoring of changes on the quality of ambient air is a field of advantage of ion mobility spectrometry. Benzene, Toluene, and Xylene are substances of special interest because of their toxicity. We present an optimized drift tube for ion mobility spectrometers, which uses photo-ionization tubes to produce the ions to be analyzed. The actual version of this drift tube has a length of 45 mm, an electric field strength established within the drift tube of about 180 V/cm and a shutter-opening-time of 400 mus. With the hydrogen tube used for ionisation a mean flux of 10(exp 12) photons/sq cm s was established for the experiments described. We discuss the results of investigations on Benzene, Toluene, and Xylene in normal used gasoline SUPER. The detection limits obtained with the ion mobility spectrometer developed in co-operation are in the range of 10 ppbv in this case. Normally, charge transfer from Benzene ions to Toluene takes place. Nevertheless the simultaneous determination in mixtures is possible by a data evaluation procedure developed for this case. The interferences found between Xylene and others are rather weak. The ion mobility spectra of different concentrations of gasoline SUPER are attached as an example for the resolution and the detection limit of the instrument developed. Resolution and sensitivity of the system are well demonstrated. A hand-held portable device produced just now is to be tested for special environmental analytical problems in some industrial and scientific laboratories in Germany.

  11. Investigation of benzene and toluene layers on 0001 surface of graphite by means of neutron scattering

    The structures of benzene (C6H6, C6D6) and toluene (C6H5-CH3, C6D5-CD3) monolayers on the basal planes of graphite have been investigated by neutron diffraction. The dynamics of the benzene layer has been studied by observing the incoherently, inelastically scattered neutrons using the time-of-flight method. The main results are: Above a phase transition temperature Tsub(c)approx.=145 K benzene on the basal planes of graphite forms a quasi 2D-fluid with high compressibility. For toluene a fluid phase exists above 140 K, between 70 K and 140 K it forms an incommensurate layer and below 70 K a 3x3 structure has been observed. The fluid phase of adsorbed benzene shows a broad quasielastic scattering indicating an effective surface diffusion coefficient of 10-4 cm2/s at 200 K. The inelastic spectrum has been compared with an appropriate lattice dynamical model. The comparison with the data reveals, can be considered as a fairly anharmonic 2D-solid with a static external potential due to the substrate. (orig./HK)

  12. Biofiltration of odours - industrial pilot to treat methyl ethyl ketone and toluene

    Methyl ethyl ketone and toluene in the off-gases of a plant producing polyvinyl chloride sheeting for the automotive industry and swimming pools caused frequent odour complaints from the neighbourhood. A pilot project was developed to investigate the removal of the compounds under actual operating conditions by passing part of the exhaust through a compost-based, three-stage biofilter. It was determined over the 156 days of operation that the removal efficiencies of methyl ethyl ketone and toluene averaged 73% and 49%, respectively. It was also shown that shutdowns and disruptions of the laminating process for short and extended periods did not affect the biofilter performance. Addition of 100g/L solution of KNO3 as a nitrogen source did not improve the performance. Carbon dioxide concentration data and the presence of an average microbial population of 52 million colony forming units per gram provided evidence that biological degradation played a significant role in the reduction of methyl ethyl ketone and toluene in the off-gases of the laminator. (author)

  13. Top-down estimates of benzene and toluene emissions in Pearl River Delta and Hong Kong, China

    Fang, X. (Xin); Shao, M.; Stohl, A.; Zhang, Q.; Zheng, J.; Guo, H.; Wang, C.; Wang, M.; Ou, J.; Thompson, R. L.; Prinn, R. G.

    2015-01-01

    Benzene (C6H6) and toluene (C7H8) are toxic to humans and the environment. They are also important precursors of ground-level ozone and secondary organic aerosols and contribute substantially to severe air pollution in urban areas in China. Discrepancies exist between different bottom-up inventories for benzene and toluene emissions in Pearl River Delta (PRD) and Hong Kong (HK), which are emission hot spots in China. This study provides top-down estimates of benzene and tolu...

  14. Top-down estimates of benzene and toluene emissions in the Pearl River Delta and Hong Kong, China

    Fang, Xuekun; Shao, Min; Stohl, Andreas; Zhang, Qiang; Zheng, Junyu; Guo, Hai; Wang, Chen; WANG, MING; Ou, Jiamin; Thompson, Rona L.; Ronald G. Prinn

    2016-01-01

    Benzene (C6H6) and toluene (C7H8) are toxic to humans and the environment. They are also important precursors of ground-level ozone and secondary organic aerosols and contribute substantially to severe air pollution in urban areas in China. Discrepancies exist between different bottom-up inventories for benzene and toluene emissions in the Pearl River Delta (PRD) and Hong Kong (HK), which are emission hot spots in China. This study provides top-down estimates of benzene and ...

  15. UV Fourier transform measurements of tropospheric O3, NO2, SO2, benzene, and toluene

    Using the differential optical absorption spectroscopy (DOAS) technique and a Fourier transform spectrometer, NO2, SO2, O3, benzene, and toluene were measured during three measurement campaigns held in Brussels in 1995, 1996, and 1997. The O3 concentrations could be explained as the results of the local photochemistry and the dynamical properties of the mixing layer. NO2 concentrations were anti-correlated to the O3 concentrations, is expected. SO2 also showed a pronounced dependence on car traffic. Average benzene and toluene concentrations were, respectively 1.7 ppb and between 4.4 and 6.6 pbb, but high values of toluene up to 98.8 ppb were observed. SO2 concentrations and to a lesser extent, those of NO2 and O3, were dependent on the wind direction. Ozone in Brussels has been found to be influenced by the meteorological conditions prevailing in central Europe. Comparisons with other measurements have shown that O3 and SO2 data are in general in good agreement, but our NO2 concentrations seem to be generally higher. (author)

  16. Biodegradation kinetics of benzene, toluene and xylene compounds: microbial growth and evaluation of models.

    Feisther, Vdice Amoroz; Ulson de Souza, Antnio Augusto; Trigueros, Daniela Estelita Goes; de Mello, Josiane Maria Muneronde; de Oliveira, Dborade; Guelli Ulson de Souza, Selene M A

    2015-07-01

    The biodegradation kinetics of BTX compounds (benzene, toluene, and xylene) individually and as mixtures was studied using models with different levels of sophistication. To compare the performance of the unstructured models applied in this work we used experimental data obtained here and some results published in the literature. The system description was based on the material balances of key components for batch operations, where the Monod and Andrews models were applied to predict the biodegradation of individual substrates. To simulate the biodegradation kinetics of substrate mixtures, models of substrate inhibition were applied along with the Sum Kinetics with Interaction Parameters (SKIP) models, where for two-component association toluene-xylene SKIP model presented better performance and for tri-component association benzene-toluene-xylene, the uncompetitive inhibition model was better. The kinetic parameters were estimated via a global search method known as Particle Swarm Optimization (PSO). The main result of this study is that the sophisticated biodegradation kinetics of BTX mixtures can be successfully described by applying the SKIP model, with the main advantage being the consideration of the substrate interactions. PMID:25627469

  17. UV Fourier transform measurements of tropospheric O3, NO2, SO2, benzene, and toluene.

    Vandaele, A C; Tsouli, A; Carleer, M; Colin, R

    2002-01-01

    Using the differential optical absorption spectroscopy (DOAS) technique and a Fourier transform spectrometer, NO2, SO2, O3, benzene. and toluene were measured during three measurement campaigns held in Brussels in 1995, 1996, and 1997. The O3 concentrations could be explained as the results of the local photochemistry and the dynamical properties of the mixing layer. NO2 concentrations were anti-correlated to the O3 concentrations, as expected. SO2 also showed a pronounced dependence on car traffic. Average benzene and toluene concentrations were, respectively 1.7 ppb and between 4.4 and 6.6 pbb, but high values of toluene up to 98.8 ppb were observed. SO2 concentrations and to a lesser extent, those of NO2 and 03, were dependent on the wind direction. Ozone in Brussels has been found to be influenced by the meteorological conditions prevailing in central Europe. Comparisons with other measurements have shown that 03 and SO2 data are in general in good agreement, but our NO2 concentrations seem to be generally higher. PMID:11806447

  18. Reactions of the CN radical with benzene and toluene: product detection and low-temperature kinetics.

    Trevitt, Adam J; Goulay, Fabien; Taatjes, Craig A; Osborn, David L; Leone, Stephen R

    2010-02-01

    Low-temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165, and 295 K is found to be relatively constant over this temperature range, (3.9-4.9) x 10(-10) cm(3) molecule(-1) s(-1). These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a rate coefficient of 1.3 x 10(-10) cm(3) molecule(-1) s(-1) at 105 K. At room temperature, nonexponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C(6)H(5)CN) is the only product recorded with no detectable evidence for a C(6)H(5) + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC(6)H(4)CH(3)) constitutes the only detected product. It is not possible to differentiate among the ortho, meta, and para isomers of cyanotoluene because of their similar ionization energies and the approximately 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C(6)H(5)CH(2)) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn's moon Titan ( approximately 100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K). PMID:20043665

  19. Reactions of the CN Radical with Benzene and Toluene: Product Detection and Low-Temperature Kinetics

    Trevitt, Adam J.; Goulay, Fabien; Taatjes, Craig A.; Osborn, David L.; Leone, Stephen R.

    2009-12-23

    Low temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165 and 295 K is found to be relatively constant over this temperature range, 3.9 - 4.9 x 10-10 cm3 molecule-1 s-1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a slower rate coefficient of 1.3 x 10-10 cm3 molecule-1 s-1 at 105 K. At room temperature, non-exponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C6H5CN) is the only product recorded with no detectable evidence for a C6H5 + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC6H4CH3) constitutes the only detected product. It is not possible to differentiate among the ortho, meta and para isomers of cyanotoluene because of their similar ionization energies and the ~;; 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C6H5CH2) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn?s moon Titan (~;;100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K).

  20. Reactions of the CN Radical with Benzene and Toluene: Product Detection and Low-Temperature Kinetics

    Low temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165 and 295 K is found to be relatively constant over this temperature range, 3.9 - 4.9 x 10-10 cm3 molecule-1 s-1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a slower rate coefficient of 1.3 x 10-10 cm3 molecule-1 s-1 at 105 K. At room temperature, non-exponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C6H5CN) is the only product recorded with no detectable evidence for a C6H5 + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC6H4CH3) constitutes the only detected product. It is not possible to differentiate among the ortho, meta and para isomers of cyanotoluene because of their similar ionization energies and the ? 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C6H5CH2) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn's moon Titan (?100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K).

  1. Removal of benzene and toluene from a refinery waste air stream by water sorption and biotrickling filtration

    Paolo Viotti

    2015-11-01

    Full Text Available The paper presents the results of an analysis of a two-stage pilot plant for the removal of toluene and benzene from the exhaust air of an industrial wastewater treatment plant (WWTP. The two-stage air process combines a water scrubber and a biotrickling filter (BTF in sequence, and treats air stripped from the liquid phase compartments of the WWTP. During the experimental period, the pilot plant treated an airflow of 600 Nm3h-1. Average concentrations of the waste air stream entering the water scrubber were 10.61 mg Nm-3 benzene and 9.26 mg Nm-3 toluene. The water scrubber obtained medium-high removal efficiencies (averages 51% and 60%, for benzene and toluene, respectively. Subsequent passage through the BTF allowed a further reduction of average concentrations, which decreased to 2.10 mg Nm-3 benzene and to 0.84 mg Nm-3 toluene, thereby allowing overall average removal efficiencies (REs of 80% and 91% for benzene and toluene, respectively. Results prove the benefits obtained from a combination of different removal technologies: water scrubbers to remove peak concentrations and soluble compounds, and BTFs to remove compounds with lower solubility, due to the biodegradation performed by microorganisms.

  2. Top-down estimates of benzene and toluene emissions in the Pearl River Delta and Hong Kong, China

    Fang, Xuekun; Shao, Min; Stohl, Andreas; Zhang, Qiang; Zheng, Junyu; Guo, Hai; Wang, Chen; Wang, Ming; Ou, Jiamin; Thompson, Rona L.; Prinn, Ronald G.

    2016-03-01

    Benzene (C6H6) and toluene (C7H8) are toxic to humans and the environment. They are also important precursors of ground-level ozone and secondary organic aerosols and contribute substantially to severe air pollution in urban areas in China. Discrepancies exist between different bottom-up inventories for benzene and toluene emissions in the Pearl River Delta (PRD) and Hong Kong (HK), which are emission hot spots in China. This study provides top-down estimates of benzene and toluene emissions in the PRD and HK using atmospheric measurement data from a rural site in the area, Heshan, an atmospheric transport model, and an inverse modeling method. The model simulations captured the measured mixing ratios during most pollution episodes. For the PRD and HK, the benzene emissions estimated in this study for 2010 were 44 (12-75) and 5 (2-7) Gg yr-1 for the PRD and HK, respectively, and the toluene emissions were 131 (44-218) and 6 (2-9) Gg yr-1, respectively. Temporal and spatial differences between the inversion estimate and four different bottom-up emission estimates are discussed, and it is proposed that more observations at different sites are urgently needed to better constrain benzene and toluene (and other air pollutant) emissions in the PRD and HK in the future.

  3. Top-down estimates of benzene and toluene emissions in Pearl River Delta and Hong Kong, China

    Fang, X.; Shao, M.; Stohl, A.; Zhang, Q.; Zheng, J.; Guo, H.; Wang, C.; Wang, M.; Ou, J.; Thompson, R. L.; Prinn, R. G.

    2015-09-01

    Benzene (C6H6) and toluene (C7H8) are toxic to humans and the environment. They are also important precursors of ground-level ozone and secondary organic aerosols and contribute substantially to severe air pollution in urban areas in China. Discrepancies exist between different bottom-up inventories for benzene and toluene emissions in Pearl River Delta (PRD) and Hong Kong (HK), which are emission hot spots in China. This study provides top-down estimates of benzene and toluene emissions in PRD and HK using atmospheric measurement data from a rural site in the area, Heshan, an atmospheric transport model and an inverse modeling method. The model simulations captured the measured mixing ratios during most pollution episodes. For PRD and HK, the benzene emissions estimated in this study for 2010 were 44 (12-75) Gg yr-1 and 5 (2-7) Gg yr-1 for PRD and HK, respectively, and the toluene emissions were 131 (44-218) Gg yr-1 and 6 (2-9) Gg yr-1, respectively. Temporal and spatial differences between the inversion estimate and four different bottom-up emission estimates are discussed, and it is proposed that more observations at different sites are urgently needed to better constrain benzene and toluene (and other air pollutants) emissions in PRD and HK in the future.

  4. Degradation of Eu(fod)3 electronic excitation energy in benzene, toluene, and o-xylene solutions

    Ways of energy dissipation resulting from Eu(fod)3 electronic excitation in homological series of solvents-benzene, toluene and o-xylene have been studied. It is ascertained that probability of the electronic excitation energy degradation increases with an increase in the number of methyl groups at aromatic ring. The values of the activation energy of Eu(fod)3 chelate excited state quenching, which correlate with the number of methyl groups in the series benzene (35.61.3 kJ/mol), toluene (39.31.3 kJ/mol), o-xylene (54.40.8 kJ/mol), have been determined. The results obtained suggest that the main contribution to Eu(3+) electronic excitation energy degradation in homological series benzene, toluene, o-xylene is made by nonradiating energy transfer to high-frequency overtones of oscillations in the solvent C-H groups

  5. Integrated Gas Sensing System of SWCNT and Cellulose Polymer Concentrator for Benzene, Toluene, and Xylenes.

    Im, Jisun; Sterner, Elizabeth S; Swager, Timothy M

    2016-01-01

    An integrated cellulose polymer concentrator/single-walled carbon nanotube (SWCNT) sensing system is demonstrated to detect benzene, toluene, and xylenes (BTX) vapors. The sensing system consists of functionalized cellulose as a selective concentrator disposed directly on top of a conductive SWCNT sensing layer. Functionalized cellulose concentrator (top layer) selectively adsorbs the target analyte and delivers the concentrated analyte as near as possible to the SWCNT sensing layer (bottom layer), which enables the simultaneous concentrating and sensing within a few seconds. The selectivity can be achieved by functionalizing cellulose acetate with a pentafluorophenylacetyl selector that interacts strongly with the target BTX analytes. A new design of the integrated cellulose concentrator/SWCNT sensing system allows high sensitivity with limits of detection for benzene, toluene, and m-xylene vapors of 55 ppm, 19 ppm, and 14 ppm, respectively, selectivity, and fast responses (<10 s to reach equilibrium), exhibiting the potential ability for on-site, real-time sensing applications. The sensing mechanism involves the selective adsorption of analytes in the concentrator film, which in turn mediates changes in the electronic potentials at the polymer-SWCNT interface and potentially changes in the tunneling barriers between nanotubes. PMID:26848660

  6. Integrated Gas Sensing System of SWCNT and Cellulose Polymer Concentrator for Benzene, Toluene, and Xylenes

    Jisun Im

    2016-02-01

    Full Text Available An integrated cellulose polymer concentrator/single-walled carbon nanotube (SWCNT sensing system is demonstrated to detect benzene, toluene, and xylenes (BTX vapors. The sensing system consists of functionalized cellulose as a selective concentrator disposed directly on top of a conductive SWCNT sensing layer. Functionalized cellulose concentrator (top layer selectively adsorbs the target analyte and delivers the concentrated analyte as near as possible to the SWCNT sensing layer (bottom layer, which enables the simultaneous concentrating and sensing within a few seconds. The selectivity can be achieved by functionalizing cellulose acetate with a pentafluorophenylacetyl selector that interacts strongly with the target BTX analytes. A new design of the integrated cellulose concentrator/SWCNT sensing system allows high sensitivity with limits of detection for benzene, toluene, and m-xylene vapors of 55 ppm, 19 ppm, and 14 ppm, respectively, selectivity, and fast responses (<10 s to reach equilibrium, exhibiting the potential ability for on-site, real-time sensing applications. The sensing mechanism involves the selective adsorption of analytes in the concentrator film, which in turn mediates changes in the electronic potentials at the polymer-SWCNT interface and potentially changes in the tunneling barriers between nanotubes.

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

    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)

  8. 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

    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.)

  9. Substrate interactions of benzene, toluene, and para-xylene during microbial degradation by pure cultures and mixed culture aquifer slurries

    Release of petroleum hydrocarbons in the environment is a widespread occurrence. One particular concern is the contamination of drinking water sources by the toxic, water-soluble, and mobile petroleum components benzene, toluene, and xylene (BTX). Benzene, toluene, and p-xylene (BTX) were degraded by indigenous mixed cultures in sandy aquifer material and by two pure cultures isolated from the same site. Although BTX compounds have a similar chemical structure, the fate of individual BTX compounds differed when the compounds were fed to each pure culture and mixed culture aquifer slurries. The identification of substrate interactions aided the understanding of this behavior. Beneficial substrate interactions included enhanced degradation of benzene-dependent degradation of toluene and p-xylene by Arthrobacter sp. strain HCB. Detrimental substrate interactions included retardation in benzene and toluene degradation by the presence of p-xylene in both aquifer slurries and Pseudomonas incubations. The catabolic diversity of microbes in the environment precludes generalizations about the capacity of individual BTX compounds to enhance or inhibit the degradation of other BTX compounds

  10. Research on biological effects induced by γ-irradiation combined with benzene, toluene and carbon monoxide inhalation

    Objective: To explore the patterns of biological effects induced by γ-rays irradiation combined with simultaneous inhalation benzene, toluene or carbon monoxide and to analyze their antagonistic,additive or synergistic interaction. Methods: Ninety healthy male rabbits were equally divided into 9 groups. Eight of which were assigned to be test groups according to four-factor-two-dose-level orthogonal layout {L8(27) } program and the other one was the control group. The two dose-levels of these four agents were: the γ-irradiation doses were 0.0075 Gy/d and 0.0375 Gy/d, and the two concentrations of benzene, toluene and carbon monoxide were 40 +-15 and 162 +- 33 mg/m3, 90 +- 30 and 407 +- 68 mg/m3, 93 +- 4 and 278 +- 8 mg/m3, respectively. The animals were exposed to γ-irradiation combined with benzene,toluene or CO vapour 2 h a day and 5 days a week for successive 8 weeks. Variance analysis and comparison between test groups were made for analyzing the test data. Results: (1) It was showed that γ-irradiation, benzene and toluene could all induce chromosome aberrations, SCEs and micronuclei of lymphocytes and chromosome aberrations of bone marrow cells; but no effect could be seen in CO alone treated group. (2) The ratios (ω) of biological effects jointly induced by the four agents and the sum of those induced separately by them were 2.16, 1.58, 2.07, 2.67, 1.25 and 1.18 for dicentric + ring,acentric, aberration cells, total aberration, micronuclei and micronucleus cells, respectively,and it was as high as 5.97 for aberrant sperms.The ratios showed that the interactions were synergistic(ω>1). However,interactions between γ-rays and benzene was antagonistic for acentric of lymphocytes. (3) The four agents could all obviously cause decrease of weight index of testis, γ-rays,toluene and CO could all markedly reduce the number of sperms and increase the ratio of aberrant sperms. Conclusion: γ-irradiation combined with benzene, toluene and CO inhalation can lead to significant interactions which are mainly synergistic,while CO can cause obvious effects on sex gland when it is combined with γ-rays, benzene and toluene

  11. Genetic effects of thinner, benzene and toluene in Drosophila melanogaster. 2. Sex linked recessive lethal, mutations and translocations II-III

    Rosario Rodríguez Arnaiz

    1985-01-01

    Full Text Available The effects of thinner, benzene and toluene on the;induction of sex-linked recessive lethal mutations and translocations 11-111 in D~osophila melanogaster were investigated by means of a genetic scheme designed. by Oster and a modified z for statistical analysis. Thinner induced sex-linked recessive lethals while benzene and toluene did not. Translocations 11-111 were produced only by benzene.

  12. Combined effects of simultaneous γ-rays irradiation and inhalation of benzene, toluene and carbon monoxide on rabbits

    Combined effects on rabbits induced by γ-rays irradiation in combination with inhalation of benzene, toluene and carbon monoxide and the interactive characteristics (antagonistic, additive or synergistic) of these agents were studied. Ninety healthy male rabbits were equally divided into 9 groups, eight of which were test groups assigned according to four factor- two-dose-level orthogonal layout [L8(27)] program and one was the control. The two dose-levels of the four factors were: for γ-rays irradiation, 0.0075 Gy/d and 0.0375 Gy/d, and for benzene, toluene and carbon monoxide, 40 +- 15 mg/m3 and 182 +- 33 mg/m3, 90 +- 30 mg/m3 and 407 +- 68 mg/m3, 93 +- 4 mg/m3 and 278 +- 8 mg/m3 respectively. The animals were exposed to γ-rays irradiation combined with benzene, toluene and CO vapor 2h a day and 5 days a week for a period of 8 weeks. Experimental results were analysed with the method of variance analysis and the test groups were compared. The results showed that (1) the interactive factor, the ratio (ω) of the combined effects caused by the four agents to the sum of the four independent effects induced by those agents, was 2.16, 1.58, 2.07, 2.67, 1.31 and 1.18 for dicentric + ring, acentric, aberration cells, total aberration, micronuclei and SCEs/C in lymphocytes respectively, and the ratio for aberrant sperms was as high as 5.97. The ratios showed that interactions were mainly synergistic (ω > 1). However, for acentric interactions between γ-rays and benzene was antagonistic. (2) The four agents could all obviously cause decrease in testis weight index, and γ-rays, benzene and CO could markedly reduce the number of sperms and increase the ratio of aberrant sperms. The interactions between γ-rays and benzene for the decrease in testis weight index and for the elevation of the ratio of aberrant sperms were synergistic. (3) CO could cause decrease in total amount of leucocytes, thrombocytes and hemoglobin, and toluene cause decrease in lymphocytes. (4) Gamma rays irradiation combined with inhalation of benzene, toluene and CO could produce significant interactions which were mainly synergistic, and CO, when combined with γ-rays, benzene and toluene, could cause obvious effects on gland

  13. Genotoxicity and apoptosis in Drosophila melanogaster exposed to benzene, toluene and xylene: Attenuation by quercetin and curcumin

    Monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylene are being extensively used for various industrial and household purposes. Exposure to these hydrocarbons, occupationally or non-occupationally, is harmful to organisms including human. Several studies tested for toxicity of benzene, toluene and xylene, and interestingly, only a few studies looked into the attenuation. We used Drosophila model to test the genotoxic and apoptotic potential of these compounds and subsequently evaluated the efficiency of two phytochemicals, namely, quercetin and curcumin in attenuating test chemical induced toxicity. We exposed third instar larvae of wild type Drosophila melanogaster (Oregon R+) to 1.0-100.0 mM benzene, toluene or xylene, individually, for 12, 24 and 48 h and examined their apoptotic and genotoxic potential. We observed significantly (P < 0.001) increased apoptotic markers and genotoxicity in a concentration- and time-dependent manner in organisms exposed to benzene, toluene or xylene. We also observed significantly (P < 0.001) increased cytochrome P450 activity in larvae exposed to test chemicals and this was significantly reduced in the presence of 3',4'-dimethoxyflavone, a known Aryl hydrocarbon receptor (AhR) blocker. Interestingly, we observed a significant reduction in cytochrome P450 activity, GST levels, oxidative stress parameters, genotoxic and apoptotic endpoints when organisms were exposed simultaneously to test chemical along with quercetin or curcumin. The study further suggests the suitability of D. melanogaster as an alternate animal model for toxicological studies involving benzene, toluene and xylene and its potential in studying the protective role(s) of phytochemicals.

  14. Wetlands for the remediation of BTEX [benzene, toluene, ethylbenzene, xylenes] contamination: Amalgamation of policy and technology

    The fate and transport of benzene, toluene, ethylbenzene, and xylenes (BTEX) as they pass from a groundwater to a surface water environment was studied in three separate field experiments. The first examined the fate of BTEX from a spilled gasoline plume as it travelled vertically in the groundwater flow regime from a mineral soil unit through an organic soil unit to a surface wetland. The second considered surface water processes in the swamp that result in losses of BTEX concentrations. The final experiment evaluated the effects of seasonal and temporal changes on the processes occurring in the swamp that affect the fate and transport of BTEX under natural flow conditions. Significant reductions in BTEX were observed as the plume travelled vertically to reach the surface water. Reductions in contaminant levels were primarily due to sorption and biodegradation. On reaching the surface, overall reduction of compound concentration over 6 m of horizontal flow ranged from 92% for benzene to 85% for m-xylene. BTEX losses were mainly due to dilution, volatilization, and sorption. Limitations existing in the approach taken by present legislation and guidelines for wetland protection are discussed. Reactive legislation and guidelines should allow natural remediation of contamination in wetlands to be considered, especially when contaminant remediation requires alteration of the hydrologic flow regime or removal of contaminated material that may result in elimination of the wetland. 70 refs., 20 figs., 14 tabs

  15. Thermodynamics of mixtures containing oxaalkanes. 6. Random mixing in ether + benzene, or + toluene systems

    The Flory model has been applied to linear or cyclic ether + benzene, or +toluene mixtures. In addition, the relative variation of the molar excess enthalpy, HmE, along homologous series of the considered systems, has been discussed taking into account the contributions to HmE from the ether-ether, aromatic-aromatic and ether-aromatic interactions. It has been shown that in CH3(CH2)u-1O(CH2CH2O)v(CH2)u-1CH3 + benzene mixtures, the u increase (v fixed) leads to a weakening of interactions between unlike molecules, and that proximity effects also weaken this type of interactions. In contrast, the v increase (u fixed) or cyclization lead to stronger interactions between unlike molecules. From the application of the model, it is concluded that the random mixing hypothesis may be considered to be valid to a large extent for many of the investigated solutions. Erroneously, strong orientational effects are predicted for 1,3-dioxolane, or 1,4-dioxane + benzene systems, but this has been attributed to the model can not describe asymmetric HmE curves when the mixture compounds show close values for Vi (molar volume) and for Vi* (reduction parameter for volume). Previous calculations on the basis of the Kirkwood-Buff integrals formalism confirm that the mixture structure is close to random mixing. Flory results on the excess molar volumes have been discussed taking into account the so-called curvature and P* contributions to this excess function.

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

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

    2014-12-01

    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. PMID:25360539

  17. Optimization of SPE for Analysis of Mandelic Acid as a Biomarker of Exposure to Ethyl Benzene

    SJ Shahtaheri, M Abdollahi, F Golbabaei, A Rahimi-Froushani, F Ghamari

    2004-01-01

    Ethyl benzene is an important constituent of widely used solvents in industries and laboratories, causing widespread environmental and industrial pollutions. For evaluation of occupational exposure to such pollutants, biological monitoring is an essential process, in which, preparation of environmental and biological samples is one of the most time-consuming and error-prone aspects prior to chromatographic techniques. The use of solid-phase extraction (SPE) has been grown and is a fertile tec...

  18. Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene.

    Rene, Eldon R; Kar, Saurajyoti; Krishnan, Jagannathan; Pakshirajan, K; López, M Estefanía; Murthy, D V S; Swaminathan, T

    2015-08-01

    The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12-0.95g/m(3)), toluene (0.14-1.48g/m(3)) and gas-flow rate (0.024-0.072m(3)/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6-41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects. PMID:25827361

  19. Adsorption of vapor-phase VOCs (benzene and toluene) on modified clays and its relation with surface properties

    Lopez-Cortes, C.; Gallardo-Velazquez, T.; Arellano-Cardenas, S. [National School of Biological Sciences (Mexico). Biophysics Dept.; Osorio-Revilla, G. [National School of Biological Sciences (Mexico). Biochemical Engineering Dept.

    2008-04-15

    A study was conducted to investigate the potential use of modified clays for the adsorption of volatile organic compounds (VOCs) present in air. These VOCs which include toluene and benzene, are among the main air pollutants that represent a human health risk at high concentrations, mostly in indoor environments. In this study, a Mexican bentonite was used to prepare 3 modified clays, notably an organoclay (OC-CPC) by intercalating cetylpyridinium chloride (CPC); an aluminum-pillared clay (Al-PILC); and an inorganic-organic clay (IOC-CPC) prepared from Al-PILC intercalating CPC. Their structures were differentiated by infrared and thermogravimetric analyses, and the interlayer distance was assessed through X-ray diffraction. Toluene and benzene adsorption on OC-CPC was higher than in IOC-CPC and Al-PILC. Natural clay showed no adsorption capacity for these compounds. Comparison of the gas chromatography retention times for non polar and low-polarity compounds (octyne and benzene) in columns packed with OC-CPC and a commercial non polar column (squalene) showed that the OC-CPC possessed a higher organophilic (non polar) nature than squalene. This explains the higher benzene and toluene adsorption capacity of the OC-CPC compared with the other modified clays. It was concluded that organoclays represent a potential alternative for the adsorption of volatile organic compounds such as benzene and toluene present in indoor environments. Since the OC-CPC is hydrophobic by nature, the relative humidity of water vapour in the environment would not affects its adsorption capacity. 27 refs., 5 tabs., 5 figs.

  20. Feasibility the Biological Monitoring of Workers Exposed to Benzene and Toluene via Measuring the Parent Compounds in the Exhaled Breath

    Hosseini

    2015-08-01

    Full Text Available Background Solvents such as benzene and toluene are commonly used in tire manufacturing, and significant occupational exposure to these chemicals adversely affects the health of workers. In biological monitoring, a complementary method for personal monitoring, the internal absorbed dose is measured and individual, environmental, and exposure differences are taken into consideration. Objectives The present study evaluated external doses by personal monitoring and investigated a more practical approach to biological monitoring by measuring the internal doses of benzene and toluene in workers involved in tire manufacturing. Materials and Methods Personal monitoring of 100 workers in tire factories A and B (n = 50 samples from each factory, n = 100 total personal samples was performed using the national institute for occupational safety and health 1501 method. Biological monitoring of the workers was performed by collecting exhaled air in Tedlar bags (n = 100. Personal and biological samples were analyzed by a gas chromatograph equipped with a flame ionization detector. Data were analyzed by independent t-test and correlation coefficients. Results There were no significant differences between factories with respect to worker age or work history. Personal exposure to benzene exceeded the current threshold limit value in 68% of workers. Occupational exposure to benzene and toluene as external (i.e. in the breathing area and internal doses (i.e. in the exhaled air were significantly higher in factory B than factory A. In addition, the external and internal doses of both compounds were significantly correlated. Conclusions The workplace conditions of tire factories must be improved. The biological exposure index can be calculated by determining the unchanged benzene and toluene concentrations in exhaled air; this can be used as a more reliable method for personal monitoring.

  1. The Role of Acid Strength of Modified NaX Zeoliteson Gas Phase Ethylation of Benzene

    Sanghamitra Barman

    2010-01-01

    Full Text Available The role of acid strength of modified NaX zeolites in gas phase ethylation of benzene were studied over Ce exchanged NaX zeolite of different types. Acidity of the modified zeolite was investigated by means of adsorbing ammonia at different temperature. The conversion of reactantsvaries with the acid strength as well as the different types of the zeolites. The strong acid sites are active centers while the weak acid sites are inactive. The influences of various process parameters such as temperature, space-time and the feed ratio of benzene to ethanol on benzene conversion over most acidic zeolite were studied. The kinetic and adsorption constants of the rate equations were estimated by the best fit. From the estimated kinetic constants, the activation energies and frequency factors for various reactions were determined. The activation energy values compared well with those reported by other investigators for same reactions over similar catalysts.

  2. Risk assessment of volatile organic compounds benzene, toluene, ethylbenzene, and xylene (BTEX) in consumer products.

    Lim, Seong Kwang; Shin, Han Seung; Yoon, Kyung Sil; Kwack, Seung Jun; Um, Yoon Mi; Hyeon, Ji Hyeon; Kwak, Hyo Min; Kim, Ji Yun; Kim, Tae Young; Kim, Yeon Joo; Roh, Tae Hyun; Lim, Duck Soo; Shin, Min Kyung; Choi, Seul Min; Kim, Hyung Sik; Lee, Byung-Mu

    2014-01-01

    Exposure and risk assessment was performed by evaluating levels of volatile organic compounds (VOC) benzene, toluene, ethylbenzene, and xylene (BTEX) in 207 consumer products. The products were categorized into 30 different items, consisting of products of different brands. Samples were analyzed for BTEX by headspace-gas chromatography/mass spectrometry (headspace-GC/MS) with limit of detection (LOD) of 1 ppm. BTEX were detected in 59 consumer products from 18 item types. Benzene was detected in whiteout (ranging from not detected [ND] to 3170 ppm), glue (1486 ppm), oil-based ballpoint pens (47 ppm), and permanent (marking) pens (2 ppm). Toluene was detected in a leather cleaning product (6071 ppm), glue (5078 ppm), whiteout (1130 ppm), self-adhesive wallpaper (15-1012 ppm), shoe polish (806 ppm), permanent pen (609 ppm), wig adhesive (372 ppm), tapes (2-360 ppm), oil-based ballpoint pen (201 ppm), duplex wallpaper (12-52 ppm), shoes (27 ppm), and air freshener (13 ppm). High levels of ethylbenzene were detected in permanent pen (ND-345,065 ppm), shoe polish (ND-277,928 ppm), leather cleaner (42,223 ppm), whiteout (ND-2,770 ppm), and glue (ND-792 ppm). Xylene was detected in permanent pen (ND-285,132 ppm), shoe polish (ND-87,298 ppm), leather cleaner (12,266 ppm), glue (ND-3,124 ppm), and whiteout (ND-1,400 ppm). Exposure assessment showed that the exposure to ethylbenzene from permanent pens ranged from 0 to 3.11 mg/kg/d (men) and 0 to 3.75 mg/kg/d (women), while for xylene, the exposure ranges were 0-2.57 mg/kg/d and 0-3.1 mg/kg/d in men and women, respectively. The exposure of women to benzene from whiteout ranged from 0 to 0.00059 mg/kg/d. Hazard index (HI), defined as a ratio of exposure to reference dose (RfD), for ethylbenzene was 31.1 (3.11 mg/kg/d/0.1 mg/kg/d) and for xylene (2.57 mg/kg/d/0.2 mg/kg/d) was 12.85, exceeding 1 for both compounds. Cancer risk for benzene was calculated to be 3.2 × 10(-5) based on (0.00059 mg/kg/d × 0.055 mg/kg-d(-1), cancer potency factor), assuming that 100% of detected levels in some products such as permanent pens and whiteouts were exposed in a worst-case scenario. These data suggest that exposure to VOC via some consumer products exceeded the safe limits and needs to be reduced. PMID:25343298

  3. Analysis of benzene, toluene, ethylbenzene and xylenes in soils by headspace and gas chromatography/flame ionization detector

    Jurandir Pereira Pinto

    2006-02-01

    Full Text Available The constituents of gasoline: benzene, toluene, ethylbenzene and xylenes (BTEX are frequently found in soils due to leaks in fuel storage tanks and they present chronic toxicity. In this work it was developed and validated a methodology of BTEX analysis in soil by gas chromatography/ flame ionization detector and static headspace. The recovery of BTEX in soil samples was evaluated using soils with different textures (sandy and loamy. The analysis method showed good resolution, in a low time of analysis (less than 30 minutes. Limits of quantification of 0.05 mg Kg soil for benzene, toluene, ethylbenzene and xylenes are below the guiding values that range from 0.15 to 95 mg Kg soil, established to determine soil quality. It was verified that the methodology enables the use of this method for BTEX analysis of soil samples for passive environmental identification of gas stations.

  4. Mutual diffusion of binary liquid mixtures containing methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride

    Guevara-Carrion, Gabriela; Janzen, Tatjana; Muñoz-Muñoz, Y. Mauricio; Vrabec, Jadran

    2016-03-01

    Mutual diffusion coefficients of all 20 binary liquid mixtures that can be formed out of methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride without a miscibility gap are studied at ambient conditions of temperature and pressure in the entire composition range. The considered mixtures show a varying mixing behavior from almost ideal to strongly non-ideal. Predictive molecular dynamics simulations employing the Green-Kubo formalism are carried out. Radial distribution functions are analyzed to gain an understanding of the liquid structure influencing the diffusion processes. It is shown that cluster formation in mixtures containing one alcoholic component has a significant impact on the diffusion process. The estimation of the thermodynamic factor from experimental vapor-liquid equilibrium data is investigated, considering three excess Gibbs energy models, i.e., Wilson, NRTL, and UNIQUAC. It is found that the Wilson model yields the thermodynamic factor that best suits the simulation results for the prediction of the Fick diffusion coefficient. Four semi-empirical methods for the prediction of the self-diffusion coefficients and nine predictive equations for the Fick diffusion coefficient are assessed and it is found that methods based on local composition models are more reliable. Finally, the shear viscosity and thermal conductivity are predicted and in most cases favorably compared with experimental literature values.

  5. Characterization of methane, benzene and toluene-oxidizing consortia enriched from landfill and riparian wetland soils.

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2010-12-15

    The microbial oxidations of methane (M) and volatile organic compounds (VOCs) were compared with those of M and VOCs alone after enriching soil samples with M and/or VOCs. Landfill cover and riparian wetland soils from which M and VOCs were simultaneously emitted were selected as representative samples. Benzene (B) and toluene (T) were employed as the model VOCs. With the landfill soil consortia, the rate of M oxidation decreased from 4.15-5.56 to 2.26-3.42 μmol g-dry soil(-1)h(-1) in the presence of both B and T, but with the wetland soil consortia the rate of M oxidation (3.09 μmol g-dry soil(-1)h(-1)) in the mixture of M as well as both B and T was similar to that of M alone (3.04 μmol g-dry soil(-1)h(-1)). Compared with the methanotrophic community with M alone, the portion of type II methanotrophs was greater in the landfill consortia; whereas, the proportion in wetland consortia was less in the presence of both B and T. The oxidations of B and T were stimulated by the presence of M with both the landfill and wetland consortia. There were no correlations between the oxidation rate of M and those of B and T with the gene copy numbers of pmoA and tmoA responsible for the oxidations. PMID:20832163

  6. Substrate interactions of benzene, toluene, and para-xylene during microbial degradation by pure cultures and mixed culture aquifer slurries.

    Alvarez, P J; Vogel, T M

    1991-01-01

    Benzene, toluene, and p-xylene (BTX) were degraded by indigenous mixed cultures in sandy aquifer material and by two pure cultures isolated from the same site. Although BTX compounds have a similar chemical structure, the fate of individual BTX compounds differed when the compounds were fed to each pure culture and mixed culture aquifer slurries. The identification of substrate interactions aided the understanding of this behavior. Beneficial substrate interactions included enhanced degradati...

  7. Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and o-Xylene in Sediment-Free Iron-Reducing Enrichment Cultures

    Jahn, Michael K.; Haderlein, Stefan B.; Meckenstock, Rainer U.

    2005-01-01

    Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX) are widespread contaminants in groundwater. We examined the anaerobic degradation of BTEX compounds with amorphous ferric oxide as electron acceptor. Successful enrichment cultures were obtained for all BTEX substrates both in the presence and absence of AQDS (9,10-anthraquinone-2,6-disulfonic acid). The electron balances showed a complete anaerobic oxidation of the aromatic compounds to CO2. This is the first...

  8. Complete Genome Sequences of Pseudomonas monteilii SB3078 and SB3101, Two Benzene-, Toluene-, and Ethylbenzene-Degrading Bacteria Used for Bioaugmentation

    Dueholm, Morten Simonsen; Albertsen, Mads; D'Imperio, Seth; Tale, Vaibhav P; Lewis, Derrick; Nielsen, Per Halkjær; Nielsen, Jeppe Lund

    2014-01-01

    Pseudomonas monteilii SB3078 and SB3101 are benzene-, toluene-, and ethylbenzene-degrading strains used for bioaugmentation in relation to treatment of wastewater contaminated with petrochemical hydrocarbons. Complete genome sequencing of the bioaugmentation strains confirms that they are very...

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

    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/m3 for benzene, 18,3 and 253 mg/m3 for toluene and 11,8 and 122,2 mg/m3 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/m3 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

  10. Concentrations of benzene and toluene in the atmosphere of the southwestern area at the Mexico City Metropolitan Zone

    Bravo, H.; Sosa, R.; Sanchez, P. [Universidad Autonoma de Mexico, Ciudad Universitaria (Mexico). Centro de Ciencias de la Atmosfera; Bueno, E.; Gonzalez, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia, SEMARNAP, Mexico (Mexico)

    2002-08-01

    The Mexico City Metropolitan Zone (MCMZ) presents important emissions of hazardous air pollutants. It is well documented that the MCMZ suffers a critical air pollution problem due to high ozone and particulate matter concentrations. However, toxic air pollutants such as benzene and toluene have not been considered. Benzene has accumulated sufficient evidence as a human carcinogen, and the ratio benzene/toluene is an excellent indicator to evaluate control strategies efficiency. In order to evaluate the levels of these two air toxic pollutants in the MCMZ, ambient air samples were collected in canisters and analyzed with a gas chromatograph with a flame ionization detector, according to procedures described in the United States Environmental Protection Agency (USEPA) method TO-15. Quality assurance was performed collecting duplicate samples which were analyzed in replicate to quantify the precision of air-quality measurements. Three different sites located in the Southwestern area in the MCMZ were selected for the sampling: the University campus, a gas station, and a vertical condominium area, in the same neighborhood, which presents different activities. At these sites, grab air samples were collected during the morning hours (7-8 a.m.), while for the University area, 24 h integrated air samples were collected simultaneously, with grab samples. Benzene concentrations (24 h sampling) in the atmosphere around the University campus have similar present levels as in other cities of North America. Mean values in this site were about 1.7 ppb. A significant variation exists between the benzene and toluene concentrations in the studied sites, being the more critical values than those registered at the gas station (an average of 25.8 ppb and a maximum of 141 ppb of benzene). There is a fuel regulation for gasoline in Mexico, which allows a maximum of 1 percent of benzene. However, since more than 60 percent of vehicles do not have catalytic converters (models before 1991) it is expected that most of this benzene be emitted through exhaust pipe. Another strategy being implemented is the use of vapor recovery systems at the gas stations. Vehicles emission control technology must be matched with adequate fuel characteristics in the problem area where it will be implemented, to achieve maximum emission reductions. (author)

  11. Optimization of Solid Phase Micro-Extraction (SPME for Monitoring Occupational Exposure to Ethyl Benzene

    H Heidari

    2012-05-01

    Full Text Available

    Background and Objectives: Analytical methods for volatile organic compounds (VOCs in different samples need extraction of compounds, by applying hazardous solvents. Solid phase micro-extraction (SPME is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are generally present in urine only at trace levels, therefore, a sensitive procedure is needed for their trace determinations. Throughout this study, headspace solid phase micro-extraction (HS-SPME was followed by GC-FID for ethyl benzene in spiked urine was optimized.

    Methods: In this study, the parameters influencing SPME and gas chromatography of ethyl benzene, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were investigated.

    Results: Extraction procedure was performed at 30°C for 6 min, using 0.2 gml-1 of NaCl in the sample solution. The sample volume and sample pH were optimized at 5 ml and 7 (neutral pH, respectively. Desorption of the ethyl benzene was carried out for 60 sec. at 250°C. The method was also validated with three different spiked urine samples and illustrated an appropriate reproducibility over six consecutive days as well as six within-day experiments. During this investigation, parameters of accuracy, linearity, and detection limits of the procedure were also evaluated.

    Conclusion: The developed method of HS- SPME-GC-FID proved to be a simple, convenient, and practical procedure, and was successfully used for measuring of ethyl benzene in spiked urine.

  12. Hydrogeochemical modeling of enhanced benzene, toluene, ethylbenzene, xylene (BTEX) remediation with nitrate

    Eckert, Paul; Appelo, C. A. J.

    2002-08-01

    During a 5-month field test, active remediation of a benzene, toluene, ethylbenzene, xylene (BTEX)-contaminated aquifer was initiated by injecting water with varying amounts of KNO3. The experiment was performed prior to selecting bioremediation for full-scale cleanup, particularly to evaluate the competing reaction of nitrate with hydrocarbons and reduced sulfur components. The nitrate oxidized sulfides that had precipitated earlier as a result of the natural degradation of BTEX with SO42- from groundwater. When the sulfides were exhausted, BTEX degradation was enhanced by nitrate. A hydrogeochemical model with kinetic oxidation reactions for Fe(II), FeS and BTEX by nitrate was developed to calculate the observed concentration patterns along a flow line in the aquifer. The rates for the kinetic model were based on published kinetic reaction equations for oxidation with oxygen. Nitrate was introduced in the equations in the same form as oxygen, with a premultiplier added to fit the observed concentration changes in the aquifer. The oxidation of Fe(II) with nitrate in the aquifer was 4 times slower than the abiological oxidation reaction with oxygen in water. Similar rates were found for oxidation of FeS with nitrate as for FeS2 with oxygen, but the specific surface area of FeS in the aquifer was larger. The reaction rate for degradation of BTEX compounds was about 107 times faster than for natural organic matter. BTEX release from pools in the aquifer was modeled with a linear driving force equation in which the pollutant/water interfacial area was linked to the mass of BTEX. The release rate and the denitrification rate were used to calculate the initial amounts of BTEX at the start of the KNO3 injection. This study shows that an assessment of the efficiency of nitrate addition for stimulating bioremediation has to consider possible reactions of nitrate with reduced sulfur components and ferrous iron.

  13. Development of portable preconcentration-gas chromatography system for fast analysis of trace benzene, toluene and xylene in air

    An automated on-line portable preconcentration-short column gas chromatography was developed, which used preconcentrator using adsorption tube with Tenax-GR and Curie-point heating. The developed system operated with 3 steps of processing, preconcentration, thermal desorption, and analysis and cleaning, and could continued operating within 1 ∼ 2 min cycle. The recoveries of preconcentrator for toluene was ranged between 94.7±6.6% and 103.8±3.1% with less than 7% of RSD. For benzene, toluene and xylene(BTX) standard gas test, IDL was 41, 49, 472 ng/m3 benzene, toluene and ο-xylene, respectively. The BTX mixture was analyzed within 30 sec with baseline separation by the system equipped with 4 m long capillary column. The deficiency of separation power caused by short column was solved by the control of sample injection volume and inlet/outlet pressure ratio. The automated portable preconcentration-short column gas chromatograph system was found to be useful for the continuous air monitoring of BTX at ppb levels ambient air

  14. Airborne determination of the temporo-spatial distribution of benzene, toluene, nitrogen oxides and ozone in the boundary layer across Greater London, UK

    Shaw, M. D.; Lee, J. D.; Davison, B.; Vaughan, A.; Purvis, R. M.; Harvey, A.; Lewis, A. C.; Hewitt, C. N.

    2015-05-01

    Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NOx) and ozone (O3) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in situ using a proton transfer reaction mass spectrometer (PTR-MS), NOx by dual-channel NOx chemiluminescence and O3 mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO2 and NOx respectively. Linear regression analysis between NO2, benzene and toluene mixing ratios yields a strong covariance, indicating that these compounds predominantly share the same or co-located sources within the city. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.5 ppbv ppbv-1), indicative of strong local sources. Daytime maxima in NOx, benzene and toluene mixing ratios were observed in the morning (~ 40 ppbv NOx, ~ 350 pptv toluene and ~ 200 pptv benzene) and in the mid-afternoon for ozone (~ 40 ppbv O3), all at 360 ± 10 m a.g.l.

  15. Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and o-Xylene in Sediment-Free Iron-Reducing Enrichment Cultures

    Jahn, Michael K.; Haderlein, Stefan B.; Meckenstock, Rainer U.

    2005-01-01

    Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX) are widespread contaminants in groundwater. We examined the anaerobic degradation of BTEX compounds with amorphous ferric oxide as electron acceptor. Successful enrichment cultures were obtained for all BTEX substrates both in the presence and absence of AQDS (9,10-anthraquinone-2,6-disulfonic acid). The electron balances showed a complete anaerobic oxidation of the aromatic compounds to CO2. This is the first report on the anaerobic degradation of o-xylene and ethylbenzene in sediment-free iron-reducing enrichment cultures. PMID:15933041

  16. Determination of Benzene, Toluene and Xylene (BTX) Concentrations in Air Using HPLC Developed Method Compared to Gas Chromatography

    Abdulrahman Bahrami; Hosien Mahjub; Marzieh Sadeghian; Farideh Golbabaei

    2011-01-01

    A new method for analysis of benzene, toluene, and xylene (BTX) using High Performance Liquid Chromatography-UV detection (HPLC-UV) is described and compared to the gas chromatography (GC) method. A charcoal adsorption tube connected to a small pump was used to obtain samples from an atmosphere chamber standard. Samples were extracted with methanol and analyzed by HPLC-UV. Chromatography was isocratic in a mobile phase consisting of water-methanol (30-70). The flow rate was set at 1 ml/min. T...

  17. Removal of benzene and toluene from a refinery waste air stream by water sorption and biotrickling filtration

    Paolo Viotti; Marco Schiavon; Renato Gavasci; Andrea G. Capodaglio

    2015-01-01

    The paper presents the results of an analysis of a two-stage pilot plant for the removal of toluene and benzene from the exhaust air of an industrial wastewater treatment plant (WWTP). The two-stage air process combines a water scrubber and a biotrickling filter (BTF) in sequence, and treats air stripped from the liquid phase compartments of the WWTP. During the experimental period, the pilot plant treated an airflow of 600 Nm3h-1. Average concentrations of the waste air stream entering the w...

  18. Health Risk Assessment of Ambient Air Concentrations of Benzene, Toluene and Xylene (BTX in Service Station Environments

    Benjamin Edokpolo

    2014-06-01

    Full Text Available 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 < 1 were obtained for all other scenarios with benzene suggesting minimal risk for most of the exposed population. However, HQ50 and HQ95 < 1 was also found with toluene and xylene for all scenarios, suggesting minimal health risk. The lifetime excess Cancer Risk (CR and Overall Risk Probability for cancer on exposure to benzene was calculated for all Scenarios and this was higher amongst service station attendants than any other scenario.

  19. Comparative study of the effects of toluene, benzene, 1,1,1-trichloroethane, diethyl ether, and flurothyl on anxiety and nociception in mice

    The main purpose of this study was to compare the effects of solvents from different chemical classes on anxiety and nociception. Independent groups of mice were exposed to air (control group), toluene (1000-4000 ppm), benzene (1000-4000 ppm), 1,1,1-trichloroethane (TCE, 2000-12000 ppm), diethyl ether (10,000-30,000) or flurothyl (200-600 ppm). After a 30-min exposure, animals were tested either in the anxiety paradigm conditioned defensive burying (CDB) test or in the hot plate test. All solvents but flurothyl produced anxiolytic-like actions being the order of potency toluene > benzene > TCE > diethyl ether. When tested in the hot plate paradigm, toluene and TCE increased nociception, benzene and diethyl ether had no effects, and flurothyl decreased nociception Additional groups of mice were conditioned to recognize the aversive stimulus (electrified prod) prior to toluene exposure and then tested in the CDB test. In unconditioned animals, toluene increased the number of shocks that mice received; however, when mice had previous experience in the CDB test, toluene lacked this effect. Taken together, these results show that inhalants have different effects with different potencies both in the CDB and in the hot plate tests. Additionally, data suggest that acute administration of toluene could impair learning

  20. Tar removal from biosyngas in the biomass gasification process. (Liquid + liquid) equilibrium {water + solvent (paraxylene and methyl hexadecanoate) + model molecules of tar (benzene, toluene, phenol)}

    Highlights: ► (Liquid + liquid) equilibria at atmospheric pressure. ► Solubility of benzene (or toluene or phenol) in paraxylene at (303 to 343) K. ► Solubility of benzene (or toluene or phenol) in methyl palmitate or methyl hexadecanoate at (303 to 343) K. ► Correlation of LLE using NRTL model. - Abstract: Tar is generated in the process by the condensation of the gas resulting from biomass gasification. The objective of this work is a contribution to the database on thermodynamic quantity which will be useful at the operation of tar removal from aqueous medium. With this aim, (liquid + liquid) equilibrium of {water + solvent (paraxylene and methyl hexadecanoate) + model molecules of tar (benzene, toluene, phenol)} was studied at temperatures (303.2, 323.2, and 343.2) K. The data obtained were correlated with the non-random two-liquid (NRTL) model.

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

    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)

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

    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

  3. Determination of benzene, toluene and xylene concentration in humid air using differential ion mobility spectrometry and partial least squares regression.

    Maziejuk, M; Szczurek, A; Maciejewska, M; Pietrucha, T; Szyposzyńska, M

    2016-05-15

    Benzene, toluene and xylene (BTX compounds) are chemicals of greatest concern due to their impact on humans and the environment. In many cases, quantitative information about each of these compounds is required. Continuous, fast-response analysis, performed on site would be desired for this purpose. Several methods have been developed to detect and quantify these compounds in this way. Methods vary considerably in sensitivity, accuracy, ease of use and cost-effectiveness. The aim of this work is to show that differential ion mobility spectrometry (DMS) may be applied for determining concentration of BTX compounds in humid air. We demonstrate, this goal is achievable by applying multivariate analysis of the measurement data using partial least squares (PLS) regression. The approach was tested at low concentrations of these compounds in the range of 5-20ppm and for air humidity in a range 0-12g/kg. These conditions correspond to the foreseeable application of the developed approach in occupational health and safety measurements. The average concentration assessment error was about 1ppm for each: benzene, toluene and xylene. We also successfully determined water vapor content in air. The error achieved was 0.2g/kg. The obtained results are very promising regarding further development of DMS technique as well as its application. PMID:26992504

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

    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. PMID:26141898

  5. Measurements of NO2, SO2, O3, benzene and toluene using differential optical absorption spectroscopy (DOAS) in Shanghai, China.

    Hao, Nan; Zhou, Bin; Chen, Dan; Sun, Yi; Gao, Song; Chen, Limin

    2006-01-01

    NO2, SO2, O3, benzene, and toluene were measured in Taopu industry park of Shanghai during the period June to August 2003 by differential optical absorption spectroscopy (DOAS) technique. The daily average concentrations of SO2, NO2, and O3 ranged from 5.7 ppb to 40 ppb, 22 ppb to 123 ppb, and 10.6 ppb to 23 ppb respectively. SO2 and NO2 concentrations were found to depend on wind direction. The diurnal variation of NO2 concentrations had two peaks due to traffic emission. Our DOAS measurements of NO2, SO2 and O3 were compared with the conventional measurement instruments (API automatic monitoring instrument). The concept of a percent difference (PD) and linear regression methods were employed to study the difference between DOAS and API instruments. The correlation analysis between PD values and meteorological parameters and analysis of abnormal higher absolute PD values indicated that the lower visibility induced the bad compatibility between the two systems. The results showed that both systems exhibited strong compatibility with good correlation, therefore the DOAS system is able to provide reliable information on distribution patterns of major air pollutants. Average benzene and toluene concentrations were 1.4 and 8.0 ppb respectively. PMID:16948427

  6. Evaluation of seawater contamination with benzene, toluene and xylene in EHE Ubatuba Region and study of their degradation by ionizing radiation

    A major concern with leaking petroleum is the environmental contamination by 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 xylenes, and their removal by exposure to 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 headspace concentrator with MSGC detector. The minimal detected limits (MDL) obtained at FIDGC were of 0.50 ?g/L for benzene, 0.70 /L for toluene, and 1.54 /L for xylenes, and the obtained experimental variability was 15%. While the concentrator type Headspace system with MS detector showed higher MDL, about of 9.30 mg/L for benzene, 8.50 mg/L for toluene, and 9.80 mg/L for xylenes, and 10% of experimental variability. In the studied area the benzene concentration varied from 1.0 ?g/L to 2.0 ?g/L, the concentration of toluene varied from 60Co. The results showed 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. For toluene the removal were from 20% to 60% with 15 kGy and xylenes were removed from 20% to 80% with 15 kGy and similar concentrations. (author)

  7. Experimental and theoretical study of surface tension of binary mixtures of (n-alkyl acetates + heptane, benzene, and toluene)

    Surface properties of binary mixtures of (n-alkyl acetates + heptane, benzene, and toluene) have been measured by surface tension method at T = 298.15 K and atmospheric pressure. Also, the surface tension has been predicted based on the Suarez method. This method combines a model for the description of surface tension of liquid mixtures with a group contribution method for the calculation of activity coefficient. The mean relative standard deviations obtained from the comparison of experimental (measured) and calculated surface tension values for the eight binary systems are less than 1.5%, which leads to concluding that the model shows a good accuracy in different situations in comparison with other predicted equations. In addition, the relative Gibbs adsorption and the surface mole fraction have been evaluated using this model. The surface tension deviations were calculated from experimental results and have been fitted to the Redlich-Kister type polynomial relation

  8. Human urine certified reference material CZ 6010: creatinine and toluene metabolites (hippuric acid and o-cresol) and a benzene metabolite (phenol)

    Šperlingová, I.; Dabrowská, L.; Stránský, V.; Kučera, Jan; Tichý, M.

    2007-01-01

    Roč. 387, č. 7 (2007), s. 2419-2424. ISSN 1618-2642 Institutional research plan: CEZ:AV0Z10480505 Keywords : toluene metabolites * benzene metabolite * human urine Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.867, year: 2007

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

    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 60Co, 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)

  10. Separation of toluene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at T = 298.15 K and atmospheric pressure

    In this paper, the separation of toluene from aliphatic hydrocarbons (heptane, or octane, or nonane) was analyzed by solvent extraction with 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid, [EMpy][ESO4]. Liquid-liquid equilibrium (LLE) data for the ternary systems {heptane (1) + toluene (2) + [EMpy][ESO4] (3)}, {octane (1) + toluene (2) + [EMpy][ESO4] (3)}, and {nonane (1) + toluene (2) + [EMpy][ESO4] (3)} were obtained by measurements at T = 298.15 K and atmospheric pressure. The selectivity, % removal of aromatic, and solute distribution ratio, obtained from experimental equilibrium results, were used to determine the ability of [EMpy][ESO4] as a solvent. The degree of consistency of the experimental LLE values was ascertained using the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were correlated with the NRTL model. Finally, the results obtained were compared with other ionic liquids and other solvents.

  11. Optimization of SPE for Analysis of Mandelic Acid as a Biomarker of Exposure to Ethyl Benzene

    SJ Shahtaheri, M Abdollahi, F Golbabaei, A Rahimi-Froushani, F Ghamari

    2004-10-01

    Full Text Available Ethyl benzene is an important constituent of widely used solvents in industries and laboratories, causing widespread environmental and industrial pollutions. For evaluation of occupational exposure to such pollutants, biological monitoring is an essential process, in which, preparation of environmental and biological samples is one of the most time-consuming and error-prone aspects prior to chromatographic techniques. The use of solid-phase extraction (SPE has been grown and is a fertile technique of sample preparation as it provides better results than those of liquid-liquid extraction (LLE. In this study, SPE using bonded silica has been optimized with regard to sample pH, sample concentration, elution solvent, elution volume, sorbent type, and sorbent mass. Through experimental evaluation, a strong anion exchange silica cartridge (SAX has been found successful in simplifying sample preparation. The present approach proved that, mandelic acid could be retained on SAX sorbent based on specific interaction. Further study was employed using 10% acetic acid to extract the analyte from spiked urine and gave a clean sample for HPLC-UV system. In this study, a high performance liquid chromatography, using reverse-phase column was used. The isocratic run was done at a constant flow rate of 0.85 ml/min, the mobile phase was water/methanol/acetic acid and a UV detector was used, setting at 225 nm. At the developed conditions the extraction recovery was exceeded 98%. The factors were evaluated statically and also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments.

  12. Modeling annual benzene, toluene, NO2, and soot concentrations on the basis of road traffic characteristics

    The investigation of potential adverse health effects of urban traffic-related air pollution is hampered by difficulties encountered with exposure assessment. Usually public measuring sites are few and thereby do not adequately describe spatial variation of pollutant levels over an urban area. In turn, individual monitoring of pollution exposure among study subjects is laborious and expensive. We therefore investigated whether traffic characteristics can be used to adequately predict benzene, NO2, and soot concentrations at individual addresses of study subjects in the city area of Munich, Germany. For all road segments with expected traffic volumes of at least 4000 vehicles a day (n=1840), all vehicles were counted manually or a single weekday in 1995. The proportion of vehicles in 'stop-go' mode, n estimate of traffic jam, was determined. Furthermore, annual concentrations of benzene, NO2, and soot from 18 high-concentration sites means: 8.7, 65.8, and 12.9 μg/m3, respectively) and from 16 school sites with moderate concentrations (means: 2.6, 32.2, and 5.7 μg/m3, respectively) were measured from 1996 to 1998. Statistical analysis of the data was performed using components of two different statistical models recently used to predict air pollution levels in comparable settings. Two traffic characteristics, traffic volume and traffic jam percentage, adequately described air pollutant concentrations (R2: 0.76-0.80, P=0.0001). This study shows that air pollutant concentrations can be accurately predicted by two traffic characteristics and that these models compare favorably with other more complex models in the literature

  13. Irradiation with benzene, toluene and phenol electron beams in aqueous solution; Irradiacion con haces de electrones de benceno, tolueno y fenol en solucion acuosa

    Santoyo O, E.L.; Lopez V, H.; Vazquez A, O.; Lizama S, B.E.; Garcia F, M. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    It is described a methodology for waste water treatment which is simulated doing a benzene-toluene-phenol mixture in aqueous solution. Three different concentrations of them ones were used which were irradiated with electron beams coming from a Pelletron Accelerator carrying out the degradation effect of these compounds in CO{sub 2} and H{sub 2}O. By mean of gas chromatography the analytical determinations were realized finding that in lower concentration of benzene and toluene performances of degradation higher than 95 % were obtained, but higher concentrations (100 ppm) the performance diminishes at 89 %, while for phenol in higher concentrations its degradation is over 60 % and in lower concentrations the degradation is under 80 %. The results are obtained with a constant irradiation time of 12 seconds and neutral pH. (Author.

  14. Application of porous membrane-protected chitosan microspheres to determine benzene, toluene, ethylbenzene, xylenes and styrene in water.

    Naing, Nyi Nyi; Li, Sam Fong Yau; Lee, Hian Kee

    2016-05-27

    Chitosan (CS) microspheres were synthesized by the precipitation method and cross-linked with glutaraldehyde. The cross-linked CS microspheres (20mg) were used as sorbents for the micro-solid phase extraction (μ-SPE) of benzene, toluene, ethylbenzene, xylenes and styrene (BTEX-S) from water. The μ-SPE device consisted of a sealed polypropylene envelope housing the microspheres for the evaluation of the extraction efficiency. Analysis was by gas chromatography-mass spectrometry (GC-MS). Under the optimized conditions, the method provided linearity range of between 0.5 and 50μgL(-1) with good correlation coefficients of between 0.985 and 0.998. The relative standard deviations of μ-SPE coupled with GC-MS were found to be between 2 and 3%. Method detection limits for BTEX-S were in the range of between 0.01 and 0.04μgL(-1) while the relative recoveries were in the range of between 59 and 97%. The proposed method is a cost effective, fast and environmentally friendly extraction technique with ease of operation and minimal usage of organic solvent. PMID:27131960

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

    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.

  16. Determination of Benzene, Toluene and Xylene (BTX Concentrations in Air Using HPLC Developed Method Compared to Gas Chromatography

    Abdulrahman Bahrami

    2011-01-01

    Full Text Available A new method for analysis of benzene, toluene, and xylene (BTX using High Performance Liquid Chromatography-UV detection (HPLC-UV is described and compared to the gas chromatography (GC method. A charcoal adsorption tube connected to a small pump was used to obtain samples from an atmosphere chamber standard. Samples were extracted with methanol and analyzed by HPLC-UV. Chromatography was isocratic in a mobile phase consisting of water-methanol (30-70. The flow rate was set at 1 ml/min. The analyses were completely separated and were quantified using both methods. The results demonstrated no statistically significant differences between BTX concentrations between the two analytical methods with a correlation coefficient of 0.98-0.99. The GC method provided higher sensitivity than HPLC, but the HPLC determination of BTX were applicable to real samples because its sensivity was lower than the thershold limit recommended by the American Conference of Governmental Industrial Hygienist (ACGIH for an 8-hour workday.

  17. Radiolysis ob benzene, toluene and phenol aqueous solutions utilizing high energy electron beam; Radiolisis de benceno, tolueno y fenol en solucion acuosa utilizando haces de electrones

    Gonzalez Vanderhaghen, D.E

    1998-12-31

    In a search for solutions to environmental pollution problems, radiolysis has proved to be an innovative technique for the removal of organic chemical pollutants in aqueous solution. Radiolysis has shown many advantages over many other techniques, as highly reactive species formed in water by ionizing radiation oxidize organic pollutants breaking down organic molecules to final simple products by oxidation to carbon dioxide and water in a complete oxidation. Our work consisted in doing some experiments in radiolysis with simulated polluted water to help us understand this technique and also develop, in a near future, a project for large scale water treatment. Our project includes the application of a Pelletron type Mexican made Electron Accelerator, which will affirm its capability and usefulness in performing investigation in this field of study. Experiments consisted in treating benzene, toluene and phenol aqueous solutions with an Electron Beam (0.48-0.55 MeV; 24 {mu}A). Two concentrations were used for each compound: 5 and 20 ppm (mg/l) for benzene and toluene; 10 and 50 ppm for phenol. Solutions were prepared with pure, mineral free water and two different p H (5.9), in order to study the effect of concentration and p H on removal efficiency, but avoiding the interference of radical scavengers. Results obtained coincide with the ones reported by Cooper, Nickelsen and Kurucz; highly efficient removal was achieved for benzene (>99.8%), toluene (>98.0%) and phenol (>88%). There was no visible important effect of p H on radiolysis efficiency for benzene nor toluene, phenol however, showed lower removal efficiency in acidic conditions. Concentration of aqueous solutions, nevertheless, did show an important effect at low doses for phenol. Results obtained reveal the importance of this technique in water pollution control and water remedial as expressed by Cooper, Nickelsen and Kurucz, who have studied radiolysis of organic compounds and apply this technique in water site remedial with a mobile Electron Beam facility. (Author)

  18. Direct detection of benzene, toluene, and ethylbenzene at trace levels in ambient air by atmospheric pressure chemical ionization using a handheld mass spectrometer.

    Huang, Guangming; Gao, Liang; Duncan, Jason; Harper, Jason D; Sanders, Nathaniel L; Ouyang, Zheng; Cooks, R Graham

    2010-01-01

    The capabilities of a portable mass spectrometer for real-time monitoring of trace levels of benzene, toluene, and ethylbenzene in air are illustrated. An atmospheric pressure interface was built to implement atmospheric pressure chemical ionization for direct analysis of gas-phase samples on a previously described miniature mass spectrometer (Gao et al. Anal. Chem.2006, 78, 5994-6002). Linear dynamic ranges, limits of detection and other analytical figures of merit were evaluated: for benzene, a limit of detection of 0.2 parts-per-billion was achieved for air samples without any sample preconcentration. The corresponding limits of detection for toluene and ethylbenzene were 0.5 parts-per-billion and 0.7 parts-per-billion, respectively. These detection limits are well below the compounds' permissible exposure levels, even in the presence of added complex mixtures of organics at levels exceeding the parts-per-million level. The linear dynamic ranges of benzene, toluene, and ethylbenzene are limited to approximately two orders of magnitude by saturation of the detection electronics. PMID:19879158

  19. Monitoring of gas station attendants exposure to benzene, toluene, xylene (BTX) using three-color chromosome painting

    2014-01-01

    Background Chronic exposure of BTX (benzene, toluene, xylene) may lead to progressive degeneration of bone marrow, aplastic anemia and/or leukemia. In Brazil there is no self-service fuel in gas stations and attendants fill the fuel themselves. Due to this they are chronically exposed to high concentration of BTX. Occupational exposure to benzene has been associated with increased chromosomal aberrations in peripheral blood lymphocytes. Fluorescence in situ hybridization (FISH) using whole chromosome painting (wcp) probes allows the rapid detection of chromosomal aberration. In the present study three-color wcp probes for chromosomes 1, 2 and 4 were used for monitoring 60 gas station attendants. Results Blood tests were done and interviews were conducted for each worker. For searching for possible associations between the clinical characteristics and the frequency of chromosomal aberrations the workers were divided into two groups (≤ 10 chromosomal abnormalities per 1,000 metaphases and > 10 chromosomal abnormalities per 1,000 metaphases).The studied workers had a low median age (36 year), albeit long period of BTX exposure (median was 16 years). Low prevalence of smoking and moderate consumption of alcoholic beverages were found in this population. The cytogenetic analysis showed 16.6% (10/60) of workers with a high frequency of chromosomal abnormalities (>10 chromosomal abnormalities per 1,000 metaphases). Translocations were the most frequently observed chromosome aberration. The statistical analysis revealed highly significant differences in skin color (p = 0.002) and a weak significant differences in gender (p = 0.052) distribution between the two groups. Conclusion 16.6% of the studied population showed elevated frequencies of chromosomal abnormalities, which is highly likely to be correlated with their exposure to BTX during their work. Therefore, further studies are needed for better characterize the work associated damage of the genome in gas station workers. It is necessary to better understand the risks that these workers are exposed, so that we can be effective in preventing diseases and maintaining the health of these workers and possibly the offspring. PMID:24576355

  20. Demographic, residential, and behavioral determinants of elevated exposures to benzene, toluene, ethylbenzene, and xylenes among the U.S. population: results from 1999-2000 NHANES.

    Symanski, Elaine; Stock, Thomas H; Tee, P Grace; Chan, Wenyaw

    2009-01-01

    Volatile organic compounds (VOC) represent a broad spectrum of compounds and there is growing concern that VOC exposures, in addition to increasing risks for cancer, may be implicated in exacerbating asthma and other adverse respiratory effects. Yet little is known about exposures in the U.S. population beyond the seminal Total Exposure Assessment Methodology (TEAM) studies that were conducted by the U.S. Environmental Protection Agency (U.S. EPA) between 1979 and 1987. This investigation was carried out to evaluate the relationship between personal exposures to benzene, toluene, ethylbenzene, and xylenes (BTEX) and socioeconomic, behavioral, demographic, and residential characteristics using a subsample from the National Health and Nutrition Examination Survey (NHANES) (636 participants who represented an estimated 141,363,503 persons aged 20 to 59 yr in the United States). Personal VOC exposures were evaluated using organic vapor monitors for periods that ranged from 48 to 72 h, and participants were administered a questionnaire regarding personal behaviors and residential characteristics while wearing the monitor. Geometric mean (GM) levels were significantly higher for males for all compounds except toluene. For benzene, GM levels were elevated among smokers and Hispanics. Sociodemographic characteristics could not be evaluated simultaneously in the weighted multiple regression models with the VOC questionnaire data because of issues associated with multicollinearity. Results from the regression analyses suggest that the presence of an attached garage (BTEX), having windows closed in the home during the monitoring period (benzene, toluene), pumping gasoline (toluene, ethylbenzene, and xylenes), or using paint thinner, brush cleaner, or stripper (xylenes) results in higher exposure in the general population and confirm previous findings of studies that were more regional in scope. Once the complete NHANES VOC data are released, additional study is warranted to explore whether risk factors associated with elevated VOC exposures differ in subgroups of U.S. adults, which should inform efforts to develop approaches for minimizing VOC exposures and ameliorating environmental health risks. PMID:19557620

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

    Marcelo Henrique Otenio; Maria Teresa Lopes da Silva; Maria Luiza Oliveira Marques; Jos Carlos Roseiro; Ederio Dino Bidoia

    2005-01-01

    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...

  2. Poly(,'-dibromo--ethyl-benzene-1,3-disulphonamide) and ,,','-tetrabromobenzene-1,3-disulphonamide as novel catalysts for synthesis of quinoxaline derivatives

    Ramin Ghorbani-Vaghei; Somaye Hajinazari

    2013-03-01

    Poly(,'-dibromo--ethyl-benzene-1,3-disulphonamide) [PBBS] and ,,','-tetrabromobenzene-1,3-disulphonamide [TBBDA] were used as efficient catalysts for the synthesis of quinoxaline derivatives in excellent yields from 1,2-diamines and 1,2-dicarbonyls under aqueous and solvent-free conditions.

  3. Experimental density, viscosity, interfacial tension and water solubility of ethyl benzene-α-methyl benzyl alcohol–water system

    Highlights: • Properties were measured for MBA (methyl benzyl alcohol)-EB (ethyl benzene)-water. • MBA concentration was found to influence all the properties strongly. • The water solubility, density, and viscosity increased at high MBA concentration. • The interfacial tension decreased sharply at high MBA concentration. • MBA dictates the phase separation and mass transfer of the ternary system. -- Abstract: Density, viscosity, interfacial tension, and water solubility were measured for the (α-methyl benzyl alcohol (MBA) + Ethyl benzene (EB)) system at different concentrations of MBA in contact with water and sodium hydroxide solution (0.01 mol · kg−1) as aqueous phases. The properties were measured to identify the component which plays a governing role in changing the physical properties relevant to mass transfer and phase separation of the ternary system. The concentration of MBA was found to be the major factor influencing all the properties. The water solubility, the density, and the viscosity increased notably at higher concentrations of MBA; while, the interfacial tension decreased strongly. The use of 0.01 mol · kg−1 NaOH as an aqueous phase resulted in a decrease of the interfacial tension and a minor decrease in the water solubility. The density data were correlated using a quadratic mixing rule to describe the influence of concentration at any temperature. The viscosity data are correlated using the Nissan and Grunberg and Katti-Chaudhri equations. The Szyzkowski’s equation was used to correlate the interfacial tension data. The water solubility data were described using an exponential relationship. All the correlations described the experimental physical property data adequately

  4. Separation of toluene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at T = 298.15 K and atmospheric pressure

    Gonzalez, Emilio J. [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain); Calvar, Noelia [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Facultade de Engenharia, Universidade de Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Gonzalez, Begona [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain); Dominguez, Angeles, E-mail: admguez@uvigo.e [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain)

    2010-06-15

    In this paper, the separation of toluene from aliphatic hydrocarbons (heptane, or octane, or nonane) was analyzed by solvent extraction with 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid, [EMpy][ESO{sub 4}]. Liquid-liquid equilibrium (LLE) data for the ternary systems left braceheptane (1) + toluene (2) + [EMpy][ESO{sub 4}] (3)right brace, left braceoctane (1) + toluene (2) + [EMpy][ESO{sub 4}] (3)right brace, and left bracenonane (1) + toluene (2) + [EMpy][ESO{sub 4}] (3)right brace were obtained by measurements at T = 298.15 K and atmospheric pressure. The selectivity, % removal of aromatic, and solute distribution ratio, obtained from experimental equilibrium results, were used to determine the ability of [EMpy][ESO{sub 4}] as a solvent. The degree of consistency of the experimental LLE values was ascertained using the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were correlated with the NRTL model. Finally, the results obtained were compared with other ionic liquids and other solvents.

  5. Co-adsorption of gaseous benzene, toluene, ethylbenzene, m-xylene (BTEX) and SO2 on recyclable Fe3O4 nanoparticles at 0-101% relative humidities.

    Ye, Connie Z; Ariya, Parisa A

    2015-05-01

    We herein used Fe3O4 nanoparticles (NPs) as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and m-xylene (BTEX) and sulfur dioxide (SO2), at different relative humidities (RH). X-ray diffraction, Brunauer-Emmett-Teller, and transmission electron microscopy were deployed for nanoparticle surface characterization. Mono-dispersed Fe3O4 (Fe2O3·FeO) NPs synthesized with oleic acid (OA) as surfactant, and uncoated poly-dispersed Fe3O4 NPs demonstrated comparable removal efficiencies. Adsorption experiments of BTEX on NPs were measured using gas chromatography equipped with flame ionization detection, which indicated high removal efficiencies (up to (95±2)%) under dry conditions. The humidity effect and competitive adsorption were investigated using toluene as a model compound. It was observed that the removal efficiencies decreased as a function of the increase in RH, yet, under our experimental conditions, we observed (40±4)% toluene removal at supersaturation for Fe3O4 NPs, and toluene removal of (83±4)% to (59±6)%, for OA-Fe3O4 NPs. In the presence of SO2, the toluene uptake was reduced under dry conditions to (89±2)% and (75±1)% for the uncoated and coated NPs, respectively, depicting competitive adsorption. At RH>100%, competitive adsorption reduced the removal efficiency to (27±1)% for uncoated NPs whereas OA-Fe3O4 NPs exhibited moderate efficiency loss of (55±2)% at supersaturation. Results point to heterogeneous water coverage on the NP surface. The magnetic property of magnetite facilitated the recovery of both types of NPs, without the loss in efficiency when recycled and reused. PMID:25968270

  6. Crystal structure of octa-?3-selenido-(p-toluene-sulfonato-?O)penta-kis-(tri-ethyl-phosphane-?P)-octa-hedro-hexa-rhenium(III) p-toluene-sulfonate di-chloro-methane disolvate.

    Edwards, Julia A; McDonald, Robert; Szczepura, Lisa F

    2015-09-01

    The title compound, [Re6Se8{O3SC6H4(CH3)}{P(C2H5)3}5](CH3C6H4SO3)2CH2Cl2, contains the face-capped hexa-nuclear [Re6(?3-Se)8](2+) cluster core. The [Re6Se8](2+) cluster core displays a non-crystallographic center of symmetry and is bonded through the Re(III) atoms to five tri-ethyl-phosphane ligands and one p-toluene-sulfonate ligand. One p-toluene-sulfonate counter-ion and two di-chloro-methane solvent mol-ecules are also present in the asymmetric unit. One of the ethyl chains of one triethylphos-phane ligand and one of the CH2Cl2 solvent molecules are disordered over two sets of sites (occupancy ratios 0.65:0.35 and 0.5:0.5, respectively). The Re-O(sulfon-ate) bond length of 2.123?(5)? is similar to other Re-O bond lengths of hexa-nuclear rhenium chalcogenide clusters containing other O-donor ligands such as dimethyl sulfoxide (DMSO), di-methyl-formamide (DMF) and hydroxide. PMID:26396864

  7. Crystal structure of octa-?3-selenido-(p-toluenesulfonato-?O)pentakis(triethylphosphane-?P)-octahedro-hexarhenium(III) p-toluenesulfonate dichloromethane disolvate

    Edwards, Julia A.; McDonald, Robert; Szczepura, Lisa F.

    2015-01-01

    The title compound, [Re6Se8{O3SC6H4(CH3)}{P(C2H5)3}5](CH3C6H4SO3)2CH2Cl2, contains the face-capped hexanuclear [Re6(?3-Se)8]2+ cluster core. The [Re6Se8]2+ cluster core displays a non-crystallographic center of symmetry and is bonded through the ReIII atoms to five triethylphosphane ligands and one p-toluenesulfonate ligand. One p-toluenesulfonate counter-ion and two dichloromethane solvent molecules are also present in the asymmetric unit. One of the ethyl chains of one triethylphosphane ligand and one of the CH2Cl2 solvent molecules are disordered over two sets of sites (occupancy ratios 0.65:0.35 and 0.5:0.5, respectively). The ReO(sulfonate) bond length of 2.123?(5)? is similar to other ReO bond lengths of hexanuclear rhenium chalcogenide clusters containing other O-donor ligands such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and hydroxide. PMID:26396864

  8. Heterogeneous adsorption and catalytic oxidation of benzene, toluene and xylene over spent and chemically regenerated platinum catalyst supported on activated carbon

    Shim, Wang Geun; Kim, Sang Chai

    2010-06-01

    The heterogeneous adsorption and catalytic oxidation of benzene, toluene and o-xylene (BTX) over the spent platinum catalyst supported on activated carbon (Pt/AC) as well as the chemically treated spent catalysts were studied to understand their catalytic and adsorption activities. Sulfuric aqueous acid solution (0.1N, H 2SO 4) was used to regenerate the spent Pt/AC catalyst. The physico-chemical properties of the catalysts in the spent and chemically treated states were analyzed by using nitrogen adsorption-desorption isotherm and elemental analysis (EDX). The gravimetric adsorption and the light-off curve analysis were employed to study the BTX adsorption and oxidation on the spent catalyst and its modified Pt/AC catalysts. The experimental results indicate that the spent Pt/AC catalyst treated with the H 2SO 4 aqueous solution has a higher toluene adsorption and conversion ability than that of the spent Pt/AC catalyst. A further studies of H 2SO 4 treated Pt/AC catalyst on their catalytic and heterogeneous adsorption behaviours for BTX revealed that the activity of the H 2SO 4 treated Pt/AC catalyst follows the sequence of benzene > toluene > o-xylene. The adsorption equilibrium isotherms of BTX on the H 2SO 4 treated Pt/AC were measured at different temperatures ranging from 120 to 180 C. To correlate the equilibrium data and evaluate their adsorption affinity for BTX, the two sites localized Langmuir (L2m) isotherm model was employed. The heterogeneous surface feature of the H 2SO 4 treated Pt/AC was described in detail with the information obtained from the results of isosteric enthalpy of adsorption and adsorption energy distributions. Furthermore, the activity of H 2SO 4 treated Pt/AC about BTX was found to be directly related to the Henry's constant, isosteric enthalpy of adsorption and adsorption energy distribution functions.

  9. EFFECTS OF FEED CONCENTRATION AND WATER VAPOR ON CATALYTIC COMBUSTION OF ETHYL ACETATE AND BENZENE IN AIR OVER CR-ZSM-5 CATALYST

    Ahmad Zuhairi Abdullah

    2010-09-01

    Full Text Available Catalytic combustion of ethyl acetate (EAc and benzene (Bz over chromium exchanged ZSM-5 (Si/Al=240 is reported. An 11 mm i.d. fixed-bed catalytic reactor, operated at temperatures between 100 oC and 500 oC, and under excess oxygen condition, was used for the catalytic activity measurement. Apparent order of reaction and apparent activation energy were determined by operating the reactor differentially at a gas hourly space velocity (GHSV of 78,900 h-1 and feed concentrations between 3,500 ppm to 17,700 ppm and 3,700 to 12,400 ppm for ethyl acetate and benzene, respectively. Ethyl acetate was more reactive than benzene due to highly reactive carbonyl group in the molecule. The combustion process satisfactorily fitted pseudo first-order kinetics with respect to organic concentration and a zero-order dependence on the oxygen concentration. The presence of water vapor (9,000 ppm in the feed stream was found to weaken the reactivity of these organics which could also be demonstrated with increases in the activation energy from 23.1 kJ/mole to 37.6 kJ/mole for ethyl acetate and from 27.6 kJ/mole to 46.1 kJ/mole for benzene. Water vapor was found to play a positive role in the formation of carbon dioxide yield in ethyl acetate combustion. Deactivation of catalyst by water appeared to be only temporary and the activity reverted back to its original value once the source of water vapor was removed.

  10. Separation of benzene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at several temperatures and atmospheric pressure: Effect of the size of the aliphatic hydrocarbons

    Gonzalez, Emilio J. [Departamento de Ingenieria Quimica, Universidad de Vigo, 36310 Vigo (Spain); Calvar, Noelia, E-mail: noecs@uvigo.e [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Gomez, Elena [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Dominguez, Angeles [Departamento de Ingenieria Quimica, Universidad de Vigo, 36310 Vigo (Spain)

    2010-01-15

    The ionic liquid 1-ethyl-3-methylpyridinium ethylsulfate, [EMpy][ESO{sub 4}], was studied for the separation of benzene from aliphatic hydrocarbons (octane or nonane) by solvent extraction through the determination of the (liquid + liquid) equilibrium (LLE) of the ternary systems: left braceoctane (1) + benzene (2) + [EMpy][ESO{sub 4}] (3)right brace and left bracenonane (1) + benzene (2) + [EMpy][ESO{sub 4}] (3)right brace at T = (283.15 and 298.15) K and atmospheric pressure. Binodal curves were determined using the 'cloud point' method, and tie-line compositions were obtained by density measurements. The values of selectivity and distribution coefficient, derived from the tie-line data, were used to decide if this ionic liquid can be used as potential solvent for the separation of benzene from aliphatic hydrocarbons using liquid extraction. These results were analyzed and compared to those previously reported for the systems left bracehexane + benzene + [EMpy][ESO{sub 4}]right brace and left braceheptane + benzene + [EMpy][ESO{sub 4}]right brace. The experimental results show that this ionic liquid is suitable for the extraction of benzene from mixtures containing octane and nonane. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL model. No literature data were found for the mixtures discussed in this paper.

  11. Separation of benzene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at several temperatures and atmospheric pressure: Effect of the size of the aliphatic hydrocarbons

    The ionic liquid 1-ethyl-3-methylpyridinium ethylsulfate, [EMpy][ESO4], was studied for the separation of benzene from aliphatic hydrocarbons (octane or nonane) by solvent extraction through the determination of the (liquid + liquid) equilibrium (LLE) of the ternary systems: {octane (1) + benzene (2) + [EMpy][ESO4] (3)} and {nonane (1) + benzene (2) + [EMpy][ESO4] (3)} at T = (283.15 and 298.15) K and atmospheric pressure. Binodal curves were determined using the 'cloud point' method, and tie-line compositions were obtained by density measurements. The values of selectivity and distribution coefficient, derived from the tie-line data, were used to decide if this ionic liquid can be used as potential solvent for the separation of benzene from aliphatic hydrocarbons using liquid extraction. These results were analyzed and compared to those previously reported for the systems {hexane + benzene + [EMpy][ESO4]} and {heptane + benzene + [EMpy][ESO4]}. The experimental results show that this ionic liquid is suitable for the extraction of benzene from mixtures containing octane and nonane. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL model. No literature data were found for the mixtures discussed in this paper.

  12. Two-step treatment of harmful industrial wastewater: an analysis of microbial reactor with integrated membrane retention for benzene and toluene removal

    Trusek-Holownia Anna

    2015-12-01

    Full Text Available Standards for highly toxic and carcinogenic pollutants impose strict guidelines, requiring values close to zero, regarding the degradation of such pollutants in industrial streams. In many cases, classic bioremoval processes fail. Therefore, we proposed a stream leaving the microbial membrane bioreactor (MBR that is directed to an additional membrane separation mode (NF/RO. Under certain conditions, the integrated process not only benefits the environment but may also increase the profitability of the bioreactor operation. An appropriate model was developed and tested in which the bioremoval of benzene and toluene by Pseudomonas fluorescens was used as an example. This paper presents equations for selecting the operation parameters of the integrated system to achieve the expected degree of industrial wastewater purification.

  13. Headspace solid-phase microextraction (HS-SPME) for the determination of benzene, toluene, ethylbenzene, and xylenes (BTEX) in foundry molding sand

    Dungan, R.S. [USDA ARS, Beltsville, MD (United States). Environmental Management & Byproducts Utilization Laboratory

    2005-07-01

    The use of headspace solid-phase microextraction (HS-SPME) to determine benzene, toluene, ethylbenzene, and xylenes (BTEX) in foundry molding sand, specifically a 'green sand' (clay-bonded sand) was investigated. The BTEX extraction was conducted using a 75 {mu} M carboxen-polydimethylsiloxane (CAR-PDMS) fiber, which was suspended above 10 g of sample. The SPME fiber was desorbed in a gas chromatograph injector port (280{sup o}C for 1 min) and the analytes were characterized by mass spectrometry. The effects of extraction time and temperature, water content, and clay and bituminous coal percentage on HS-SPME of BTEX were investigated. Because green sands contain bentonite clay and carbonaceous material such as crushed bituminous coal, a matrix effect was observed. The detection limits for BTEX were determined to be {lt}= 0.18 ng g{sup -1} of green sand.

  14. Exploring the C-X? halogen bonding motif: an infrared and Raman study of the complexes of CF?X (X = Cl, Br and I) with the aromatic model compounds benzene and toluene.

    Nagels, Nick; Hauchecorne, Dieter; Herrebout, Wouter A

    2013-01-01

    The formation of halogen bonded complexes formed between the trifluorohalomethanes CF?Cl, CF?Br and CF?I and the Lewis bases benzene and toluene at temperatures below 150K was investigated using FTIR and Raman spectroscopy. Experiments using liquid krypton as solvent show that for both CF?Br and CF?I substantial fractions of the monomers can be involved in 1:1 complexes. In addition, weak absorptions illustrating the formation of 2:1 complexes between CF?I and benzene are observed. Using spectra recorded at temperatures between 120 and 140 K, observed information on the relative stability was obtained for all complexes by determining the complexation enthalpies in solution. The resulting values for CF?Br.benzene, CF?I.benzene and (CF?I)?.benzene are -6.5(3), -7.6(2) and -14.5(9) kJ mol?. The values for CF?Br.toluene and CF?I.toluene are -6.2(5) and -7.4(5) kJ mol?. The experimental complexation enthalpies are compared with theoretical data obtained by combining results from MP2/aug-cc-pVDZ(-PP) and MP2/aug-cc-pVTZ(-PP) ab initio calculations, from statistical thermodynamical calculations and from Monte Carlo Free Energy Perturbation simulations. The data are also compared with results derived for other C-X? halogen bonded complexes involving unsaturated Lewis bases such as ethene and ethyne. PMID:23752468

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

    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 5.0ngmL(-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 0.01-0.06ngmL(-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%. PMID:27033984

  16. Effect of isobutanol on toluene biodegradation in nitrate amended, sulfate amended and methanogenic enrichment microcosms.

    Jayamani, Indumathy; Cupples, Alison M

    2013-09-01

    Isobutanol is an alternate fuel additive that is being considered because of economic and lower emission benefits. However, future gasoline spills could result in co-contamination of isobutanol with gasoline components such as benzene, toluene, ethyl-benzene and xylene. Hence, isobutanol could affect the degradability of gasoline components thereby having an effect on contaminant plume length and half-life. In this study, the effect of isobutanol on the biodegradation of a model gasoline component (toluene) was examined in laboratory microcosms. For this, toluene and isobutanol were added to six different toluene degrading laboratory microcosms under sulfate amended, nitrate amended or methanogenic conditions. While toluene biodegradation was not greatly affected in the presence of isobutanol in five out of the six different experimental sets, toluene degradation was completely inhibited in one set of microcosms. This inhibition occurred in sulfate amended microcosms constructed with inocula from wastewater treatment plant activated sludge. Our data suggest that toluene degrading consortia are affected differently by isobutanol addition. These results indicate that, if co-contamination occurs, in some cases the in situ half-life of toluene could be significantly extended. PMID:23224907

  17. Kinetics and mechanism of the electrochemical reduction of [1,2-bis( tert-butylperoxy)ethyl]benzene under conditions of the in situ recovery of a platinum surface

    Vedenyapina, M. D.; Sharipov, M. Yu.; Terent'ev, A. O.; Skundin, A. M.; Vedenyapin, A. A.

    2016-02-01

    The behavior of [1,2-bis( tert-butylperoxy)ethyl]benzene ( I) on Pt electrode is studied by means of cyclic voltammetry (CVA). A comparison of the electrochemical properties of I and the properties of previously studied bridge-type 1,2,4,5-tetraoxane ((1,4)-1,4-dimethyl-7-(4-methylbenzyl)-2,3,5,6-tetraoxabicyclo[2.2.1]heptane) ( II) shows that the biperoxide studied in this work is reduced on a Pt electrode at lower cathodic potentials and is resistant to electrooxidation.

  18. 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

    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)

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

    R., Balzer; L. F. D., Probst; V., Drago; W. H., Schreiner; H. V., Fajardo.

    2014-09-01

    Full Text Available Cobalt catalysts supported on ?-alumina, ceria and ?-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-desorp [...] tion 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/?-Al2O3-CeO2 catalytic systems presented the best performances. The results obtained in the characterization suggest that the higher catalytic activity of the Co20/?-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.

  20. Evaluation of the solid-phase microextraction fiber coated with single walled carbon nanotubes for the determination of benzene, toluene, ethylbenzene, xylenes in aqueous samples.

    Li, Quanlong; Ma, Xiaoxia; Yuan, Dongxing; Chen, Jinsheng

    2010-04-01

    A solid-phase microextraction (SPME) fiber coated with single walled carbon nanotubes (SWCNTs) was prepared by electrophoretic deposition and treated at 500 degrees C in H(2) stream. In order to evaluate the characteristics of the obtained fiber, it was applied in the headspace solid-phase microextraction (HS-SPME) of benzene, toluene, ethylbenzene and xylenes (BTEX) from water sample and quantification by gas chromatography with flame ionization detection (GC-FID). The results indicated that the thermal treatment with H(2) enhanced the extraction of the SWCNTs fiber for BTEX significantly. Thermal stability and durability of the fiber were also investigated, showing excellent stability up to 350 degrees C and life time over 120 times. In the comparison with the commercial CAR-PDMS fiber, the SWCNTs fiber showed similar and higher extraction efficiencies for BTEX. Under the optimized conditions, the linearity, LODs (S/N=3) and LOQs (S/N=10) of the method based on the SWCNTs fiber were 0.5-50.0, 0.005-0.026 and 0.017-0.088 microg/L, respectively. Repeatability for one fiber (n=3) was in the range of 1.5-5.6% and fiber-to-fiber reproducibility (n=3) was in the range of 4.2-8.3%. The proposed method was successfully applied in the analysis of BTEX compounds in seawater, tap water and wastewater from a paint plant. PMID:20207361

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

    Flamys Lena do N. Silva; Jos Ribeiro dos Santos Jr.; Jos Machado Moita Neto; Rosa Lina G. do N. P. da Silva; Danilo Luiz Flumignan; Jos Eduardo de Oliveira

    2009-01-01

    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 C. 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 ...

  2. Exploring the C-X? Halogen Bonding Motif: An Infrared and Raman Study of the Complexes of CF3X (X = Cl, Br and I with the Aromatic Model Compounds Benzene and Toluene

    Wouter A. Herrebout

    2013-06-01

    Full Text Available The formation of halogen bonded complexes formed between the trifluorohalomethanes CF3Cl, CF3Br and CF3I and the Lewis bases benzene and toluene at temperatures below 150K was investigated using FTIR and Raman spectroscopy. Experiments using liquid krypton as solvent show that for both CF3Br and CF3I substantial fractions of the monomers can be involved in 1:1 complexes. In addition, weak absorptions illustrating the formation of 2:1 complexes between CF3I and benzene are observed. Using spectra recorded at temperatures between 120 and 140 K, observed information on the relative stability was obtained for all complexes by determining the complexation enthalpies in solution. The resulting values for CF3Br.benzene, CF3I.benzene and (CF3I2.benzene are ?6.5(3, ?7.6(2 and ?14.5(9 kJ mol?1. The values for CF3Br.toluene and CF3I.toluene are ?6.2(5 and ?7.4(5 kJ mol?1. The experimental complexation enthalpies are compared with theoretical data obtained by combining results from MP2/aug-cc-pVDZ(-PP and MP2/aug-cc-pVTZ(-PP ab initio calculations, from statistical thermodynamical calculations and from Monte Carlo Free Energy Perturbation simulations. The data are also compared with results derived for other C-X? halogen bonded complexes involving unsaturated Lewis bases such as ethene and ethyne.

  3. Gamma radiolysis of toluene and deuterated toluenes: Pt. 1

    The ? radiolysis of liquid toluene and toluene-d8 was studied at 50degC. For toluene, product yields were 0.14 molecules of hydrogen, 0.006 of methane, 0.090 of biphenyl and 0.9 of ''polymer'' for each 100 eV absorbed. For toluene-d8, these yields are lower by a factor of two to three. Radiolysis of mixtures of toluene and toluene-d8 shows a disproportionately high decomposition of the light toluene, suggesting that energy initially absorbed in toluene-d8 transfers to toluene before decomposition occurs. Deuterium tracer studies indicate that about 14% of the hydrogen arises from unimolecular processes, whereas none of the methane or bibenzyl arises in this way. Studies using an electron scavenger, ethyl bromide, and a proton scavenger, ethanol, showed that the hydrogen yield did not likely have long-lived electrons or ions as precursors. Thus the energy transfer from toluene-d8 to toluene is probably by direct excitation transfer, and not by charge transfer. (author)

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

    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.

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

    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 lquido 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 degradao de B, T e X por Pseudomonas putida CCMI 852 contendo um plasmdeo TOL. Aps 18 a 24 horas de homogenizao da mistura, o inoculo foi adicionado e o decrscimo da concentrao dos solventes foi determinado entre 24 e 25 horas por GC. Pseudomonas putida CCMI 852 foi capaz de metabolizar T e X, mas no B. Na mistura BTX, B no foi metabolizado tambm e a velocidade de degradao de T e X decresceu cerca de 50% comparado com solues contendo apenas T ou X.

  6. 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.

    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. PMID:25911428

  7. Bis(ethyl­enediamine-κ2 N,N′)bis­(methanol-κO)copper(II) benzene-1,4-dicarboxyl­ate methanol disolvate

    Abbaszadeh, Abolfazl; Safari, Nasser; Amani, Vahid; Notash, Behrouz

    2012-01-01

    In the cation of the title compound, [Cu(C2H8N2)2(CH3OH)2](C8H4O4)·2CH3OH, the CuII atom lies on an inversion centre. The four N atoms of two ethyl­enediamine ligands around the CuII atom form the equatorial plane, while two methanol O atoms in the axial positions complete a Jahn–Teller distorted octa­hedral coordination. The benzene-1,4-dicarboxyl­ate anion is centrosymmetric. In the crystal, C—H⋯O, N—H⋯O and O—H⋯O hydrogen bonds link the cations, the anions and the methanol solvent mol­ecules. PMID:22807708

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

    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 C. 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 Piau state. Statistical analysis techniques, such as PCA and HCA were used to analyze the data. Moreover, several validation parameters were evaluated.

  9. Thermodynamics of fuels with a bio-synthetic component (IV): (Vapor + liquid) equilibrium data for the ternary mixture (ethyl 1,1-dimethylethyl ether + 1-hexene + toluene) at T = 313.15 K

    The paper reports experimental p-x data for the ternary system (ethyl 1,1-dimethylethyl ether + 1-hexene + toluene) at T = 313.15 K. The ether, synthesized from ethanol of biological origin, increases the interest of this compound as an additive for gasolines. An isothermal total pressure cell was used for the measurements. Data reduction by Barker's method provides correlations for GE, using Wilson, NRTL, UNIQUAC models and the Wohl expansion for the ternary system and the calculation of the vapor phase composition. Good results are obtained for the correlation by all the models

  10. Studies on the behavior of diluents on extraction of uranium from phosphoric acid medium using di-2 ethyl hexyl phosphoric acid as extraction

    Extraction studies of uranium from phosphoric acid medium have been carried out by di-2-ethyl hexyl phosphoric acid (D2EHPA) using different diluents viz. xylene, benzene, toluene, carbon tetra chloride, chloroform, hexane and kerosene. Higher extraction of uranium is observed from lower acidities of phosphoric acid (0.5 M) when kerosene, xylene, benzene, hexane and toluene are used as diluents kerosene being the best among these. In the acid range of 0.75-2 M xylene, hexane and toluene are better diluents. Extraction of uranium decreases as the acidity of phosphoric acid increases. Benzene and hexane are least preferred diluents with lower percentage extraction. When carbon tetrachloride and chloroform are used as diluents, it is observed that below 2 M of phosphoric acid a third phase is formed due to which mass distribution is not uniform in organic and aqueous phase and an error is observed in mass balance. (author)

  11. Correlation and prediction of the phase behavior and thermal properties of binary and ternary systems of 2,2′-oxybis[propane] + benzene, toluene, cyclohexane or n-heptane

    Didaoui, Saéda, E-mail: sdidaoui@hotmail.com [Laboratoire de thermodynamique et de modélisation moléculaire, Faculté de chimie, Université des Sciences et de la Technologie Houari Boumediene B.P.32, El-Alia Bab-Ezzouar 16111 Alger (Algeria); Ait-Kaci, Ahmed [Laboratoire de thermodynamique et de modélisation moléculaire, Faculté de chimie, Université des Sciences et de la Technologie Houari Boumediene B.P.32, El-Alia Bab-Ezzouar 16111 Alger (Algeria)

    2013-09-10

    Highlights: ► To provide original data of excess enthalpies of systems containing additive gasoline. ► To predict excess functions using statistical model. ► To examine the thermal behavior of ethers with hydrocarbons using theoretical models. ► Increasing information of thermodynamic behavior will increase quality of the fuel and economy. - Abstract: The experimental excess molar enthalpies data of liquid binary and ternary mixtures of DIPE with benzene, toluene, cyclohexane and n-heptane have been measured at 303.15 K and constant pressure using a Calvet type microcalorimeter, C80 (Setaram, France). A Redlich–Kister type equation was used to correlate experimental values. The theoretical results obtained by the DISQUAC model are significantly closer to the experimental values.

  12. Correlation and prediction of the phase behavior and thermal properties of binary and ternary systems of 2,2′-oxybis[propane] + benzene, toluene, cyclohexane or n-heptane

    Highlights: ► To provide original data of excess enthalpies of systems containing additive gasoline. ► To predict excess functions using statistical model. ► To examine the thermal behavior of ethers with hydrocarbons using theoretical models. ► Increasing information of thermodynamic behavior will increase quality of the fuel and economy. - Abstract: The experimental excess molar enthalpies data of liquid binary and ternary mixtures of DIPE with benzene, toluene, cyclohexane and n-heptane have been measured at 303.15 K and constant pressure using a Calvet type microcalorimeter, C80 (Setaram, France). A Redlich–Kister type equation was used to correlate experimental values. The theoretical results obtained by the DISQUAC model are significantly closer to the experimental values

  13. Excess enthalpies of ternary mixtures of (oxygenated additives + aromatic hydrocarbon) mixtures in fuels and bio-fuels: (Dibutyl-ether + 1-propanol + benzene), or toluene, at T = (298.15 and 313.15) K

    Highlights: • New excess enthalpy data for ternary mixtures of (dibutyl ether + aromatic hydrocarbon + 1-propanol) are reported. • 2 ternary systems at T = (298.15 and 313.15) K were measured by means of an isothermal flow calorimeter. • 230 data were fitted to a Redlich–Kister rational equation. • Intermolecular and association effects involved in these systems have been discussed. - Abstract: New experimental excess molar enthalpy data of the ternary systems (dibutyl ether + 1-propanol + benzene, or toluene), and the corresponding binary systems at T = (298.15 and 313.15) K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and ternary systems show endothermic character at both temperatures. The experimental data for the systems have been fitted using the Redlich–Kister rational equation. Considerations with respect the intermolecular interactions amongst ether, alcohol and hydrocarbon compounds are presented

  14. Benzene from Traffic

    Palmgren, F.; Berkowicz, R.; Skov, H.; Hansen, A. B.

    The measurements of benzene showed very clear decreasing trends in the air concentrations and the emissions since 1994. At the same time the measurements of CO and NOx also showed a decreasing trend, but not so strong as for benzene. The general decreasing trend is explained by the increasing...... number of petrol vehicles with three way catalysts, 60-70% in 1999. The very steep decreasing trend for benzene at the beginning of the period from 1994 was explained by the combination of more catalyst vehicles and reduced benzene content in Danish petrol. The total amount of aromatics in petrol......, including toluene, increased only weakly. The analyses of air concentrations were confirmed by analyses of petrol sold in Denmark. The concentration of benzene at Jagtvej in Copenhagen is still in 1998 above the expected new EU limit value, 5 µg/m3 as annual average. However, the reduced content of benzene...

  15. 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

    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)

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

    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. Comparao entre injeo na coluna ("on-column") e headspace dinmico na determinao de benzeno, tolueno e xilenos (BTX) em amostras de gua Comparison between on-column injection and dynamic headspace in the determination of Benzene, Toluene and Xylene (BTX) in water

    Elaine A. A. F. Gobato; Lanas, Fernando M.

    2001-01-01

    The analysis of water samples containing volatile organic compounds has become an important task in analytical chemistry. Gas chromatography has been widely used for the analysis of volatile organic compounds in water. The headspace analysis shows as a principal characteristic the possibility of determination of the volatile components in drinking water. Benzene, Toluene and Xylene (BTX) are important compounds usually present in drinking water, from contamination by petroleum derivatives. Si...

  18. Thermally enhanced bioremediation of a gasoline-contaminated aquifer using toluene oxidizing bacteria

    The combined application of steam injection and vacuum extraction has proved to be very effective for the in situ remediation of a gasoline contaminated aquifer. It is expected that the steam treated zone with its near-sterile nature, increased temperature, and decreased level of contaminant concentration will provide a superior environment for enhanced bioremediation, and will favor the survival of an introduced microbial culture for the destruction of residual gasoline hydrocarbons and especially BTEX compounds (Benzene, Toluene, Ethyl benzene, and Xylene). A mixed microbial culture seeded from the pre-steamed aquifer material was enriched in a laboratory chemostat on toluene, a major gasoline aromatic. Studies were conducted to determine the optimal conditions for microbial growth and activity. Growth rate studies conducted at different temperatures revealed that cell growth was optimal at 35 C, a temperature at which the aquifer can be maintained using the existing steam injection wells. The enriched culture was shown to degrade all BTEX compounds successfully both individually and in mixtures. Substrate toxicity was observed for some of the gasoline aromatics but at concentration levels well above those found in groundwater. When cells were exposed to mixtures of BTEX compounds, the biodegradation of xylene, the most recalcitrant aromatic among BTEX compounds, was stimulated. When cells were exposed to gasoline, BTEX degradation proceeded with no apparent inhibition by gasoline aliphatics; little aliphatic degradation took place, however, suggesting the absence of monooxygenase enzymes in the mixed culture. In mixtures of both toluene and propane enriched cultures, only dioxygenase activity was observed

  19. Temperature influence on mixing properties of {ethyl tert-butyl ether (ETBE) + gasoline additives}

    The densities and ultrasonic velocity of {ethyl tert-butyl ether (ETBE) + (benzene, toluene, ethylbenzene, isooctane, tert-butyl alcohol, and ethanol)} over the temperature range (288.15 to 323.15) K and atmospheric pressure, have been measured over the whole concentration range. The experimental excess volumes and deviation of isentropic compressibilities data have been analysed in terms of different theoretical models. The gathered data improve open literature related to gasoline additives, and help to understand the ETBE volumetric and acoustic trend into different chemical environment

  20. Poly[[[[1-ethyl-6,8-difluoro-7-(3-methylpiperazin-1-yl-4-oxo-1,4-dihydroquinoline-3-carboxylato]cadmium]-μ-benzene-1,4-dicarboxylato] trihydrate

    Xin-Ping Kang

    2010-11-01

    Full Text Available In the title layered coordination polymer, {[Cd(C17H18F2N3O3(C8H4O4]·3H2O}n, the CdII atom exhibits a very distorted CdO6 octahedral geometry defined by one O3,O4-bidentate 1-ethyl-6,8-difluoro-7-(3-methylpiperazin-1-yl-4-oxo-1,4-dihydroquinoline-3-carboxylate (lome ligand, one O,O′-bidentate benzene-1,4-dicarboxylate (bdc dianion and two O-monodentate bdc dianions. Both the bdc species in the asymmetric unit are completed by crystallographic inversion symmetry. The bridging bdc dianions link the cadmium nodes into a rectangular grid lying parallel to (01overline{1}. A network of N—H...O and O—H...O hydrogen bonds helps to establish the packing.

  1. Rapid determination of benzene derivatives in water samples by trace volume solvent DLLME prior to GC-FID

    Diao, Chun Peng; Wei, Chao Hai; Feng, Chun Hua [South China Univ. of Technology, Guangzhou Higher Education Mega Center (China). College of Environmental Science and Engineering; Guangdong Regular Higher Education Institutions, Guangzhou (China). Key Lab. of Environmental Protection and Eco-Remediation

    2012-05-15

    An inexpensive, simple and environmentally friendly method based on dispersive liquid liquid microextraction (DLLME) for rapid determination of benzene derivatives in water samples was proposed. A significant improvement of DLLME procedure was achieved. Trace volume ethyl acetate (60 {mu}L) was exploited as dispersion solvent instead of common ones such as methanol and acetone, the volume of which was more than 0.5 mL, and the organic solvent required in DLLME was reduced to a great extent. Only 83-{mu}L organic solvent was consumed in the whole analytic process and the preconcentration procedure was less than 10 min. The advantageous approach coupled with gas chromatograph-flame ionization detector was proposed for the rapid determination of benzene, toluene, ethylbenzene and xylene isomers in water samples. Results showed that the proposed approach was an efficient method for rapid determination of benzene derivatives in aqueous samples. (orig.)

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

    Luis Haro-Garca

    2012-06-01

    Full Text Available Objetivos. Evaluar las tres series celulares sanguneas e identificar la presencia de hipocroma, macrocitosis, leucopenia, linfocitopenia y trombocitopenia en un grupo de trabajadores expuestos a la mezcla de benceno-tolueno-xileno (BTX. Materiales y mtodos. Estudio transversal donde se incluy a 97 trabajadores de una empresa de pinturas de Mxico a los que se les realiz una biometra hemtica convencional y les fue estimada la exposicin a travs de la dosis diaria potencial acumulada para vapores de BTX. Resultados. Del total de trabajadores, 19,6%, mostr macrocitosis, 18,6%, linfocitopenia, 10,3% hipocroma, 7,2% trombocitopenia y 5,2% leucopenia. La asociacin cruda de macrocitosis con exposicin a dosis alta de mezcla de BTX fue la nica significativa (OR:3,6; IC95%: 1,08 - 13,9; p=0,02 y en la que se estructur un modelo de regresin logstica (OR:6,7; IC95%: 1,33 - 13,55; p:0,02 ajustada por edad, consumo de alcohol y tabaquismo. Conclusiones. Todos los componentes citohemticos analizados mostraron cambios leves; que podran estar asociados con la exposicin a la mezcla de BTX. De ellos, la macrocitosis podra constituirse en una manifestacin 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% CI 1.08 to 13.9, P = 0.02, and the base for a logistic regression model (OR: 6.7, 95% CI 1.33 to 13.55, P = 0.02 adjusted for age, alcohol consumption, and smoking. Conclusions. All blood cytological components analyzed demonstrated mild changes, potentially associated with exposure to the mixture of BTX. Macrocytosis could constitute an early manifestation worthy for surveillance.

  3. 2-{4-Methyl-N-[(2,3,4,9-tetrahydro-1H-carbazol-3-yl)methyl]benzenesulfonamido}ethyl 4-methylbenzenesulfonate

    Gmentrk, Mustafa; Ergn, Yavuz; Mougang-Soume, Berline; aylak Deliba?, Nagihan; Hkelek, Tuncer

    2013-01-01

    In the title compound, C29H32N2O5S2, the indole ring system is nearly planar, with a maximum deviation of 0.013?(2)?, and the cyclohexenone ring has an envelope conformation with the methine C atom as the flap. The two methylbenzene rings are approximately perpendicular to each other, making a dihedral angle of 89.09?(8). In the crystal, NH?O hydrogen bonds link the molecules into a chain running along the a-axis direction, and weak CH?O hydrogen bonds and CH?? interactions are observed between the chains. PMID:24454234

  4. 2-{4-Methyl-N-[(2,3,4,9-tetra-hydro-1H-carbazol-3-yl)meth-yl]benzene-sulfon-amido}-ethyl 4-methyl-benzene-sulfonate.

    Gmentrk, Mustafa; Ergn, Yavuz; Mougang-Soume, Berline; Caylak Deliba?, Nagihan; Hkelek, Tuncer

    2013-11-20

    In the title compound, C29H32N2O5S2, the indole ring system is nearly planar, with a maximum deviation of 0.013?(2)?, and the cyclo-hexenone ring has an envelope conformation with the methine C atom as the flap. The two methyl-benzene rings are approximately perpendicular to each other, making a dihedral angle of 89.09?(8). In the crystal, N-H?O hydrogen bonds link the mol-ecules into a chain running along the a-axis direction, and weak C-H?O hydrogen bonds and C-H?? inter-actions are observed between the chains. PMID:24454234

  5. 2-[(1Z-(9-Ethyl-9H-carbazol-3-ylmethyleneamino]-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrilebenzene (2/1

    Hoong-Kun Fun

    2010-05-01

    Full Text Available In the title compound, 2C24H21N3SC6H6, the two independent Schiff base molecules (A and B in the asymmetric unit differ in the orientation of the tetrahydrobenzothiophene ring system with respect to the carbazole ring system by 180 rotation about the CC bond in the CC=NC linkage. The two molecules also differ in the orientation of the ethyl groups [CNCC torsion angle of 90.7?(3 in molecule A, and ?79.4?(3 in molecule B]. In molecule B, two methylene C atoms of the cyclohexene ring are disordered over two sites with occupancies of 0.58?(1 and 0.42?(1. The cyclohexene rings in both molecules adopt half-chair conformations. The dihedral angle between the thiophene ring and the carbazole ring system is 8.07?(9 in molecule A [3.10?(9 in molecule B]. In the crystal structure, the independent molecules are linked into dimers by intermolecular CH...N hydrogen bonds. In addition, CH...? interactions are observed.

  6. Poly(N,N'-dichloro-N-ethyl-benzene-1, 3-disulfonamide) and N,N,N',N'-tetrachlorobenzene-1,3-disulfonamide as novel catalytic reagents for synthesis of bis-indolyl, tris-indolyl, di(bis-indolyl), tri(bis-indolyl) and tetra(bis-indolyl)methanes under solid-state, solvent and water conditions

    Easy and rapid preparation of bis-indolyl, tris-indolyl, di(bis-indolyl), tri(bis-indolyl) and tetra(bis-indolyl) methanes from indole with various aldehydes and ketones using poly (N,N'-dichloro-N-ethyl-benzene-1,3-disulfonamide) [PCBS] and N,N,N',N'-tetrachlorobenzene-1,3-disulfonamide [TCBDA] as novel catalysts under various conditions are here described. (author)

  7. Elastic scattering of low-energy electrons from toluene

    Sakaamini, Ahmad; Hargreaves, L. R.; Khakoo, M. A.; Pastega, D. F.; Bettega, M. H. F.

    2016-04-01

    Theoretical and normalized experimental differential, momentum transfer, and integral cross sections for vibrationally elastic scattering of low-energy electrons from toluene (C6H5C H3 ) are presented. The differential cross sections are measured at incident energies from 1 to 20 eV and scattering angles from 15° to 130°. The calculated cross sections are obtained using the Schwinger multichannel method with pseudopotentials in the static-exchange plus polarization approximation. Comparisons are made between the present theory and measurements with earlier available measurements. In general, the agreement between the theory and the experiment is very good. We also discuss the resonance spectra of toluene, where we find three π* shape resonances whose locations agree well with the experiment. In addition, we compare the cross sections of toluene and benzene, since the former can be considered as a benzene derivative by the substitution of a hydrogen in benzene by a C H3 group in toluene.

  8. Anticonvulsant and antipunishment effects of toluene

    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.

  9. Exposure Evaluation for Benzene, Lead and Noise in Vehicle and Equipment Repair Shops

    Sweeney, Lynn C.

    2013-04-10

    An exposure assessment was performed at the equipment and vehicle maintenance repair shops operating at the U. S. Department of Energy Hanford site, in Richland, Washington. The maintenance shops repair and maintain vehicles and equipment used in support of the Hanford cleanup mission. There are three general mechanic shops and one auto body repair shop. The mechanics work on heavy equipment used in construction, cranes, commercial motor vehicles, passenger-type vehicles in addition to air compressors, generators, and farm equipment. Services include part fabrication, installation of equipment, repair and maintenance work in the engine compartment, and tire and brake services. Work performed at the auto body shop includes painting and surface preparation which involves applying body filler and sanding. 8-hour time-weighted-average samples were collected for benzene and noise exposure and task-based samples were collected for lead dust work activities involving painted metal surfaces. Benzene samples were obtained using 3M™ 3520 sampling badges and were analyzed for additional volatile organic compounds. These compounds were selected based on material safety data sheet information for the aerosol products used by the mechanics for each day of sampling. The compounds included acetone, ethyl ether, toluene, xylene, VM&P naphtha, methyl ethyl ketone, and trichloroethylene. Laboratory data for benzene, VM&P naphtha, methyl ethyl ketone and trichloroethylene were all below the reporting detection limit. Airborne concentrations for acetone, ethyl ether, toluene and xylene were all less than 10% of their occupational exposure limit. The task-based samples obtained for lead dusts were submitted for a metal scan analysis to identify other metals that might be present. Laboratory results for lead dusts were all below the reporting detection limit and airborne concentration for the other metals observed in the samples were less than 10% of the occupational exposure limit. Noise dosimetry sampling was performed on a random basis and was representative of the different work activities within the four shops. Twenty three percent of the noise samples exceeded the occupational exposure limit of 85 decibels for an 8-hour time-weightedaverage. Work activities where noise levels were higher included use of impact wrenches and grinding wheels.

  10. Electron beam degradation of simulated toluene-containing exhaust gas

    With toluene as an example, experimental investigation on VOCs treatment by electron beam irradiation was carried out. The system uses 0.8 MeV electron beams to irradiate simulated toluene-containing gases to 5kGy-40kGy for investigatiing effects of initial concentration, absorbed dose, humidity on toluene removal rate. The toluene removal rate increased with absorbed dose. With 0.5-l.2Nm3/h of the gas flow at an initial toluene concentration of 1600mg/Nm3, the toluene removal rate was 46.5% at 10kGy and 72.2% at 40kGy. And increasing humidity increased the toluene removal rate, too. Qualitative analysis on by-products of the toluene degradation was made by means of Gas Chromatogram-Mass Spectrometer (GC/MS) and Chromatography of Ions (IC). It was found that the by-products consist of mainly benzaldehyde and formic acid, plus a little benzoic acid, benzyl alcohol, methyl pyridine, nitrotoluene, o-cresol, phenol and benzoin ethyl etherl. Mechanisms of the E-beam toluene removal, i.e. the contributions of OH free radicals and O2 to the oxidation of toluene, were discussed. (authors)

  11. Modelling and Simulation Of Benzene Alkylation Process Reactors For Production Of Ethylbenzene

    Majid Kakavand; Amir Farshi; Jafar S. Ahari; Hamid Ganji

    2004-01-01

    The goal of this paper is to develop a simulation software for the ethyl benzene production unit in aPetrochemical Complex of Iran. Ethyl benzene whose consumption has rapidly increased in recent years, isthe feed for production of styrene monomer. This material is produced from alkylation of benzene withethylene. A process simulator can play a very important role in the development of this process. In thisresearch, alkylation of benzene for production of ethylbenzene has been simulated. Firs...

  12. Quantitative trace analysis of benzene using an array of plasma-treated metal-decorated carbon nanotubes and fuzzy adaptive resonant theory techniques.

    Leghrib, Radouane; Llobet, Eduard

    2011-12-01

    The functionalization of carbon nanotube sidewalls with metal nanoparticles is exploited here to improve the sensitivity and selectivity of gas sensors operated at room temperature. An array of sensors using oxygen plasma treated multiwalled carbon nanotubes (bare and decorated with Pt, Pd or Rh nanoparticles) is shown to selectively detect traces of benzene (i.e., 100 ppb) in the presence of carbon monoxide, hydrogen sulfide or nitrogen dioxide at different humidity levels. Employing a quantitative fuzzy adaptive resonant theory (ART) network whose inputs are the responses of the sensor array, it is possible to accurately estimate benzene concentration in a changing background. The quantitative fuzzy ART is especially suited for compensating the nonlinear effects in sensor response caused by changes in ambient humidity, which explains why this method clearly outperforms partial least squares calibration models at estimating benzene concentration. These results open the way to design new affordable, wearable, sensitive and selective detectors aimed at the personal protection of workers subject to occupational exposure to benzene, toluene, ethyl benzene and xylenes. PMID:22093340

  13. Preparation of toluenes specifically labelled with C-14

    The attempt to prepare toluene-2 C-14 starting from ethyl acetoacetate failed because the reaction of sodium ethyl acetoacetate with dibromopropane could not be performed. This labelling was also attempted starting from methyl tetrahydropyran. This synthesis was not successful because the preparationof 2-methyl pimelic acid was impossible. Labellimg of carbon-3 of toluene starting from succinic acid could not be carried out because the Grignard reaction of a-ketoglutaric acid as unsuccessful. The radioactive syntheses started from propanediol resp. from c-butyrolactone. (The labelling of carbon-3 of toluene was not possible in this case because the reduction of malonic acid to propanediol could not be carried out). The synthesis course was identical for all labellings. The synthesis differed only in the introduction of the activiy from potassium cyanide C-14. The starting compounds were reacted to propanedinitril, which was saponified to glutaric acid. The acid was reduced to pentanediol. From the diol, dibromopentane was produced. Reaction with potassium cyanide yielded, after saponification, pimelic acid. The acid was cyclizated to cyclohexanone, which was reduced to cyclohexanol. The OH group was replaced by bromine and subsequently by a methyl group. Dehydration yielded toluene. The following labellings were carried out: Toluene-2, -2.6, -1.2.6, -1.2 C-14. (G.G.)

  14. Pallidol hexaacetate ethyl acetate monosolvate

    Qinyong Mao

    2013-07-01

    Full Text Available The entire molecule of pallidol hexaacetate {systematic name: (-(4bR,5R,9bR,10R-5,10-bis[4-(acetyloxyphenyl]-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-1,3,6,8-tetrayl tetraacetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12C4H8O2. The ethyl acetate molecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009. Acta Cryst. D65, 148155]; the crystallographic data take into account the presence of the solvent. In pallidol hexaacetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100? is 54.73?(6, indicating a significant fold in the molecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5 between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [CO(carboxyCC torsion angles = ?70.24?(14, ?114.43?(10 and ?72.54?(13]. In the crystal, a three-dimensional architecture is sustained by CH...O interactions which encompass channels in which the disordered ethyl acetate molecules reside.

  15. Determination of benzene in exhaust gas from biofuels. Final report; Bestimmung von Benzol im Abgas von Biokraftstoffen. Abschlussbericht

    Dutz, M.; Buenger, J.; Gnuschke, H.; Halboth, H.; Gruedl, P.; Krahl, J.

    2001-10-01

    With the advance of environmental legislation and practices oriented towards sustainability renewable energy resources are becoming increasingly important. Use of replenishable raw materials helps preserve fossil resources. In the fuel sector the most widely used replenishable materials are rape methyl ester (RME) and ethyl tertiary butyl ether (ETBE). The purpose of the present project on the ''Determination of benzene in exhaust gas from biofuels'' was to generate orienting data on the potential health relevance of mixtures of fossil and renewable fuel intended for use in spark ignition and diesel engines. This included a determination of benzene emissions and the mutagenicity of particles. Beyond the applied-for scope of research measurements were also performed on the test engine's toluene, ethyl benzene and xylene emissions as well as on the smoke spot number and nitrogen oxide (NO{sub x}) and hydrocarbon (HC) emissions of the diesel engine. [German] Regenerative Energien gewinnen durch die Umweltgesetzgebungen und das Streben nach einer nachhaltigen Entwicklung zunehmend an Bedeutung. Durch die Verwendung nachwachsender Rohstoffe koennen die fossilen Ressourcen geschont werden. Im Kraftstoffsektor sind hier hauptsaechlich Rapsoelmethylester (RME) und optional Ethyltertiaerbutylether (ETBE) zu nennen. Um fuer Diesel- und Ottomotoren insbesondere mit Blick auf Kraftstoffgemische aus fossilen und regenerativen Komponenten orientierende Daten ueber eine potenzielle Gesundheitsrelevanz zu generieren, wurde das Projekt 'Bestimmung von Benzol im Abgas von Biokraftstoffen' durchgefuehrt. Neben der Benzolemission wurde die Mutagenitaet der Partikeln ermittelt. Ueber den beantragten Untersuchungsrahmen hinaus wurden die Tuluol-, Ethylbenzol-, und Xylolemissionen der eingesetzten Motoren, sowie die Russzahl (RZ) und die Stickoxid- (NO{sub x}) und Kohlenwasserstoffemissionen (HC) des Dieselmotors bestimmt. (orig.)

  16. 2-[(1Z)-(9-Ethyl-9H-carbazol-3-yl)methyleneamino]-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrilebenzene (2/1)

    Hoong-Kun Fun; Jia Hao Goh; Asiri, Abdullah M; Salman A. Khan; Khan, Khalid A.

    2010-01-01

    In the title compound, 2C24H21N3SC6H6, the two independent Schiff base molecules (A and B) in the asymmetric unit differ in the orientation of the tetrahydrobenzothiophene ring system with respect to the carbazole ring system by 180 rotation about the CC bond in the CC=NC linkage. The two molecules also differ in the orientation of the ethyl groups [CNCC torsion angle of 90.7?(3) in molec...

  17. Investigation of a metagenomic library for aerobic toluene degradation genes

    Bouhajja, Emna; George, Isabelle; Liles, Marc; Agathos, Spiros N.; 14th International Symposium on Microbial Ecology (ISME14)

    2012-01-01

    A metagenomic study on sediment from a former gasworks site located in Düsseldorf- Flingern was conducted to assess the tar oil hydrocarbon degradation potential at that site. A sediment sample was collected from 6.70 m to 7.10 m below surface in the anoxic contaminant plume. This plume consisted mainly of benzene, toluene, ethylene, xylene and polyaromatic hydrocarbons. The first step was to extract enough high quality, high molecular weight DNA despite low cell density within the sediment. ...

  18. Biodegradation of Toluene (an LNAPL) under varying temperature and fluctuating water conditions

    Rajbhandari Shrestha, S.

    2011-01-01

    Abstract Groundwater contamination occurs when there is spill of substances which are harmful to humans and the environment. One of the most common groundwater contaminant is Non-aqueous phase liquids (NAPL). These substances are notorious as they do not mix with water and are able to persist in nature causing long term harm. They are broadly classified as Light (LNAPL) or dense (DNAPL) based on their relative density with water. BTEX (Benzene, Toluene, Ethylene benzene and Xylene) is an ...

  19. Isolation of alkali-tolerant benzene-degrading bacteria from a contaminated aquifer.

    Fahy, A.; Ball, A S; Lethbridge, G; Timmis, K. N.; McGenity, T.J.

    2008-01-01

    AIMS: To isolate benzene-degrading strains from neutral and alkaline groundwaters contaminated by benzene, toluene, ethylbenzene, xylenes (BTEX) from the SIReN aquifer, UK, and to test their effective pH range and ability to degrade TEX. METHODS AND RESULTS: The 14 isolates studied had an optimum pH for growth of 8, and could degrade benzene to below detection level (1 microg l(-1)). Five Rhodococcus erythropolis strains were able to metabolize benzene up to pH 9, two distinct R. erythropolis...

  20. Critical issues in benzene toxicity and metabolism: The effect of interactions with other organic chemicals on risk assessment

    Medinsky, M.A.; Schlosser, P.M.; Bond, J.A. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

    1994-11-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene are well documented and include aplastic anemia and pancytopenia. Some individuals exposed repeatedly to cytotoxic concentrations of benzene develop acute myeloblastic anemia. It has been hypothesized that metabolism of benzene is required for its toxicity, although administration of no single benzene metabolite duplicates the toxicity of benzene. Several investigators have demonstrated that a combination of metabolites (hydroquinone and phenol, for example) is necessary to duplicate the hematotoxic effect of benzene. Enzymes implicated in the metabolic activation of benzene and its metabolites include the cytochrome P450 monooxygenases and myeloperoxidase. Since benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. Other organic molecules that are substrates for cytochrome P450 can inhibit the metabolism of benzene. For example, toluene has been shown to inhibit the oxidation of benzene in a noncompetitive manner. Enzyme inducers, such as ethanol, can alter the target tissue dosimetry of benzene metabolites by inducing enzymes responsible for oxidation reactions involved in benzene metabolism. 24 refs., 6 figs., 2 tabs.

  1. Demand boom boosts ethyl, butyl acetate

    US ethyl and butyl acetate markets are being described as 'extremely tight.' One major domestic producer is 'in a sold-out position' and has 'gone on sales control' with respect to these two products. Producers say that sales of both ethyl and butyl acetate have increased during the past year, and industry observers say they expect to see an April 1 price initiative of 2 cts to 3 cts/lb, and possibly a second increase in October. While one producer suggests that this market strength could be 'a sign that the coatings industry is turning around,' most agree that reformulation is the principal driver of growth. Ethyl acetate is said to be replacing methyl ethyl ketone in many formulations, while butyl acetate and butyl acetate blends are substituting for methyl isobutyl ketone. In addition, both ethyl and butyl acetate work as substitutes for xylene and toluene in certain applications. In an effort to conform to the requirements of the Clean Air Act of 1990 and to cooperate with the Environmental Protection Agency's 33/50 voluntary emissions reduction program, coatings manufacturers are moving as quickly as possible to eliminate solvents from their products. And although solvents as a whole will eventually see a dramatic decline in consumption, the temporary beneficiaries of reformulation will be certain of the oxygenated solvents, says Jeff Back, business manager at Kline ampersand Co

  2. Degradative capacities and bioaugmentation potential of an anaerobic benzene-degrading bacterium strain DN11

    Yuki Kasai; Yumiko Kodama; Yoh Takahata; Toshihiro Hoaki; Kazuya Watanabe [Marine Biotechnology Institute, Kamaishi (Japan)

    2007-09-15

    Azoarcus sp. strain DN11 is a denitrifying bacterium capable of benzene degradation under anaerobic conditions. The present study evaluated strain DN11 for its application to bioaugmentation of benzene-contaminated underground aquifers. Strain DN11 could grow on benzene, toluene, m-xylene, and benzoate as the sole carbon and energy sources under nitrate-reducing conditions, although o- and p-xylenes were transformed in the presence of toluene. Phenol was not utilized under anaerobic conditions. Kinetic analysis of anaerobic benzene degradation estimated its apparent affinity and inhibition constants to be 0.82 and 11 {mu}M, respectively. Benzene-contaminated groundwater taken from a former coal-distillation plant site in Aichi, Japan was anaerobically incubated in laboratory bottles and supplemented with either inorganic nutrients (nitrogen, phosphorus, and nitrate) alone, or the nutrients plus strain DN11, showing that benzene was significantly degraded only when DN11 was introduced. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments, and quantitative PCR revealed that DN11 decreased after benzene was degraded. Following the decrease in DN11 16S rRNA gene fragments corresponding to bacteria related to Owenweeksia hongkongensis and Pelotomaculum isophthalicum, appeared as strong bands, suggesting possible metabolic interactions in anaerobic benzene degradation. Results suggest that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations. 50 refs., 6 figs., 1 tab.

  3. Survey of Extreme Solvent Tolerance in Gram-Positive Cocci: Membrane Fatty Acid Changes in Staphylococcus haemolyticus Grown in Toluene

    Nielsen, Lindsey E.; Kadavy, Dana R.; Rajagopal, Soumitra; Drijber, Rhae; Nickerson, Kenneth W.

    2005-01-01

    We exploited the unique ecological niche of oil fly larval guts to isolate a strain of Staphylococcus haemolyticus which may be the most solvent-tolerant gram-positive bacterium yet described. This organism is able to tolerate 100% toluene, benzene, and p-xylene on plate overlays and saturating levels of these solvents in monophasic liquid cultures. A comparison of membrane fatty acids by gas chromatography after growth in liquid media with and without toluene showed that in cells continuousl...

  4. 1-Ethyl-3-(2,4,6-trimethylphenylimidazolium tetrafluoroborate

    Jin-Tao Guan

    2010-08-01

    Full Text Available The title compound, C14H19N2+·BF4−, was obtained by reaction of 1-ethyl-3-(2,4,6-trimethylphenylimidazolium tetrafluoroborate with sodium tetrafluoroborate. The imidazole ring makes a dihedral angle of 78.92 (13° with the benzene ring.

  5. Anaerobic degradation of benzene by marine sulfate-reducing bacteria

    Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

    2010-05-01

    Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in analyses of metabolites with benzene-grown cultures, suggesting an activation of benzene via carboxylation.

  6. Catalytic transformation of methyl benzenes over zeolite catalysts

    Al-Khattaf, S.

    2011-02-01

    Catalytic transformation of three methyl benzenes (toluene, m-xylene, and 1,2,4-trimethyl benzene) has been investigated over ZSM-5, TNU-9, mordenite and SSZ-33 catalysts in a novel riser simulator at different operating conditions. Catalytic experiments were carried out in the temperature range of 300-400 °C to understand the transformation of these alkyl benzenes over large pore (mordenite and SSZ-33) in contrast to medium-pore (ZSM-5 and TNU-9) zeolite-based catalysts. The effect of reaction conditions on the isomerization to disproportionation product ratio, distribution of trimethylbenzene (TMB) isomers, and p-xylene/o-xylene ratios are reported. The sequence of reactivity of the three alkyl benzenes depends upon the pore structure of zeolites. The zeolite structure controls primarily the diffusion of reactants and products while the acidity of these zeolites is of a secondary importance. In the case of medium pore zeolites, the order of conversion was m-xylene > 1,2,4-TMB > toluene. Over large pore zeolites the order of reactivity was 1,2,4-TMB > m-xylene > toluene for SSZ-33 catalyst, and m-xylene ∼ 1,2,4-TMB > toluene over mordenite. Significant effect of pore size between ZSM-5 and TNU-9 was observed; although TNU-9 is also 3D 10-ring channel system, its slightly larger pores compared with ZSM-5 provide sufficient reaction space to behave like large-pore zeolites in transformation of aromatic hydrocarbons. We have also carried out kinetic studies for these reactions and activation energies for all three reactants over all zeolite catalysts under study have been calculated. © 2011 Elsevier B.V.

  7. Supercritical toluene extraction of a reduced Turkish lignite

    Aktas, Z.; Olcay, A. [Ankara University, Ankara (Turkey). Chemical Engineering Dept.

    1996-07-01

    Elbistan-Afsin lignite, 64.2% C (daf), was reduced with lithium in THF in the presence of purified naphthalene as an electron transfer agent. The reduced lignite was then extracted with supercritical toluene. Even under comparatively mild conditions, 340{degree}C, relatively large yields of supercritical extract were obtained, almost all of which dissolved in benzene. The n-pentane-soluble and benzene-soluble fractions of the extract were eluted using column chromatography. Less than half of the originally soluble material could be eluted with n-pentane or benzene, the total methanol eluates amounting to 56.1% of the initial extract. The eluates were analyzed by gas chromatography/mass spectrometry. The amount of phenol was 23.6% of the original benzene soluble fraction. It was concluded that bond cleavage had taken place during the reduction of the lignite. The naphthalene used as an electron transfer agent participated in side reactions. 46 refs., 3 figs., 8 tabs.

  8. Effect of substrate interaction on oxidation of methane and benzene in enriched microbial consortia from landfill cover soil.

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2011-01-01

    The interaction of methane and benzene during oxidation in enriched methane-oxidizing consortium (MOC) and in benzene-oxidizing consortium (BOC) from landfill cover soil was characterized. Oxidation of both methane and benzene occurred in the MOC due to the coexistence of bacteria responsible for benzene oxidation, as well as methanotrophs, whereas in the BOC, only benzene was oxidized, not methane. Methane oxidation rates in the MOC were decreased with increasing benzene/methane ratio (mol/mol), indicating its methane oxidation was inhibited by the benzene coexistence. Benzene oxidation rates in the MOC, however, were increased with increasing benzene/methane ratio. The benzene oxidation in the BOC was not affected by the coexistence of methane or by the ratio of methane/benzene ratio (mol/mol). No effect of methane or benzene was found on the dynamics of functional genes, such as particulate methane monooxygenase and toluene monooxygenase, in association with oxidation of methane and benzene in the MOC and BOC. PMID:21847790

  9. Consistent assignment of the vibrations of monosubstituted benzenes.

    Gardner, Adrian M; Wright, Timothy G

    2011-09-21

    We investigate the consistency of the labeling and assignments of the vibrations of the monosubstituted benzenes in the electronic ground state. In doing so, we also identify some inconsistencies in the labeling of the benzene modes. We commence by investigating the behavior of the benzene vibrations as one hydrogen is replaced by an artificial atomic substituent of increasing mass via quantum chemical calculations; the wavenumber variations with mass give insight into the assignments. We also examine how well the monohalobenzene vibrations can be described in terms of the benzene ones: consistent with some recent studies, we conclude that this is futile in a significant number of cases. We then show that "isotopic wavenumbers" obtained by artificially changing the mass of the fluorine atom in fluorobenzene are in very good agreement with the wavenumbers obtained via explicit calculation for the relevant monohalobenzene (chlorobenzene, bromobenzene, and iodobenzene) vibrations. As a consequence, we propose that the vibrations of monofluorobenzene be used as the basis for labelling the vibrational assignments of monosubstituted benzenes. As well as the four monohalobenzenes, we also apply this approach to the vibrations of aniline, toluene, benzonitrile, phenylacetylene, phenylphosphine, and nitrobenzene. This has allowed a much more consistent picture of the vibrational assignments to be obtained across ten monosubstituted benzenes. PMID:21950860

  10. DETERMINATION OF BENZENE IN AIR BY MICROCOLUMN ADSORPTION AND THERMAL DESORPTION IN GC INLET

    Ján Hrivňák

    2006-03-01

    Full Text Available The air sample is passed through the glass microcolumn filled with Tenax, which is then transferred into a modified GC injection port for thermal desorption and without cryofocusation analyzed. A linear working range for benzene, toluene, ethylbenzene and p-xylene at the amounts of 4-20 ng per microcolumn was established with correlation coeficients (r2 within the range, 0.99896 – 0.99952. Limit of detection for benzene (analyzing 200 ml of air sample lies under 3µg/m3. The method has been successfully applied for the determination of benzene in crossroad air.

  11. Benzene release. Status report

    Scoping benzene release measurements were conducted on 4 wt percent KTPB 'DEMO' formulation slurry using a round, flat bottomed 100-mL flask containing 75 mL slurry. The slurry was agitated with a magnetic stirrer bar to keep the surface refreshed without creating a vortex. Benzene release measurements were made by purging the vapor space at a constant rate and analyzing for benzene by gas chromatography with automatic data acquisition. Some of the data have been rounded or simplified in view of the scoping nature of this study

  12. Drying up the benzene

    Harrison, Lynda

    2011-03-15

    In 2007, a directive from the Alberta Energy Resources Conservation Board asked companies running glycol dehydrators to report their benzene emissions. In order to help companies to do so, Process Ecology Inc. developed an online system that calculates, reports and manages dehydrators benzene emissions. This Benzene Emissions Advisor collects data, runs simulation models and stores the results in a database accessible to clients through its website. This software, used by 25 per cent of the market, can now be used for energy optimization purposes. It can inform operators of many saving opportunities, for example turning down the glycol pump.

  13. Molecular jet study of the solvation of toluene by methane, ethane, and propanea)

    Schauer, Mark; Law, K. S.; Bernstein, E. R.

    1985-01-01

    Two color time of flight mass spectroscopy studies of toluene solvated by methane, ethane, and propane in a supersonic molecular jet have been carried out. This work is quite similar to the studies in the preceding paper on benzene. The conclusions and finding in the benzene investigation are strengthened and elaborated. The comparison of calculations and experiments has yielded information on binding enegy, geometry, and spectral shift. A strong correlation is found between observed cluster transition intensity and cluster nucleation processes and a tentative nucleation scheme for the molecular jet formation of solute-solvent clusters is presented.

  14. Benzene Monitor System report

    Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale open-quotes SRAT/SME/PRclose quotes and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard trademark sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system (0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge ampersand trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer's computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants)

  15. Benzene Monitor System report

    Livingston, R.R.

    1992-10-12

    Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale {open_quotes}SRAT/SME/PR{close_quotes} and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard{trademark} sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system ({+-}0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge & trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer`s computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants).

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

    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.

  17. Small scale spatial gradients of outdoor and indoor benzene in proximity of an integrated steel plant.

    Licen, Sabina; Tolloi, Arianna; Briguglio, Sara; Piazzalunga, Andrea; Adami, Gianpiero; Barbieri, Pierluigi

    2016-05-15

    Benzene is known as a human carcinogen, whose annual mean concentration exceeded the EU limit value (5μg/m(3)) only in very few locations in Europe during 2012. Nevertheless 10% to 12% of the EU-28 urban population was still exposed to benzene concentrations above the WHO reference level of 1.7μg/m(3). WHO recommended a wise choice of monitoring stations positioning in proximity of "hot spots" to define and assess the representativeness of each site paying attention to micro-scale conditions. In this context benzene and other VOCs of health concern (toluene, ethylbenzene, xylenes) concentrations have been investigated, with weekly passive sampling for one year, both in outdoor and indoor air in inhabited buildings in close proximity (180m far up to 1100m) of an integrated steel plant in NE of Italy. Even though the outdoor mean annual benzene concentration was below the EU limit in every site, in the site closest to the works the benzene concentration was above 5μg/m(3) in 14weeks. These events were related to a benzene over toluene ratio above one, which is diagnostic for the presence of an industrial source, and to meteorological factors. These information pointed at the identification of the coke ovens of the plant as the dominant outdoor source of benzene. Benzene gradients with the increasing distance from coke ovens have been found for both outdoor and indoor air. Linear models linking outdoor to indoor benzene concentrations have been then identified, allowing to estimate indoor exposure from ambient air benzene data. In the considered period, a narrow area of about 250m appeared impacted at a higher degree than the other sites both considering outdoor and indoor air. Passive BTEX sampling permits to collect information on both ambient air and daily life settings, allowing to assemble a valuable data support for further environmental cost-benefit analyses. PMID:26930323

  18. Steam reforming of toluene as model compound of biomass pyrolysis tar for hydrogen

    Steam reforming of tar during biomass pyrolysis for hydrogen will not only avoid frequent equipment shutdown for maintenance and repair but also increase hydrogen yield. In this paper, the effects of temperature and steam/carbon molar ration on steam reforming of toluene as model compound of tar was studied by simulation of thermodynamic equilibrium and experiments using Ni/cordierite catalyst in a fixed bed reactor. The results of thermodynamic simulations indicate that the S/C molar ratio of 2 and the temperature range from 1023 K to 1173 K provide favorable operating conditions for steam reforming of toluene in order to get high hydrogen productivity. These operating parameters were adopted in the experiments using Ni/cordierite catalyst in a fixed bed reactor. H2 content remains about 66 mol% and slightly varies with the increasing temperature. Conversion efficiency of toluene increases with temperature, reaching 94.1% at 1173 K. The simulation was improved in order to be closer to experimental results. It is found that only a very small amount of toluene did not participate in the reaction. In the aromatic hydrocarbons of reactive system, benzene and naphthalene were the main products and the proportion of naphthalene decreases with increasing temperature while that of benzene increases.

  19. 27 CFR 21.132 - Toluene.

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Toluene. 21.132 Section 21... TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.132 Toluene. (a..., Standard No. D 362-75 for industrial grade toluene; for incorporation by reference, see § 21.6(b).)...

  20. Maternal Exposure to Ambient Levels of Benzene and Neural Tube Defects among Offspring: Texas, 1999–2004

    Lupo, Philip J.; Symanski, Elaine; Waller, D. Kim; Chan, Wenyaw; Langlois, Peter H; Canfield, Mark A.; Mitchell, Laura E

    2010-01-01

    Background Previous studies have reported positive associations between maternal exposure to air pollutants and several adverse birth outcomes. However, there have been no studies assessing the association between environmental levels of hazardous air pollutants, such as benzene, and neural tube defects (NTDs), a common and serious group of congenital malformations. Objective Our goal was to conduct a case–control study assessing the association between ambient air levels of benzene, toluene,...

  1. Ethnic Differences in the Metabolism of Toluene: Comparisons between Korean and Foreign Workers Exposed to Toluene

    Kim, Ki-Woong; Won, Young Lim; Ko, Kyung Sun

    2015-01-01

    The objectives of this study were to investigate the individual characteristics, lifestyle habits, exposure levels, and genetic diversity of xenobiotic-metabolizing enzymes involved in toluene metabolism in Korean and foreign workers exposed to toluene at a manufacturing plant. This study was conducted to determine the effects of culture or ethnicity on toluene metabolism. The results showed that blood and urinary toluene concentrations were dependent on the level of exposure to toluene. We a...

  2. Toluene stability Space Station Rankine power system

    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. Ethyl 2-(2,3,4,5,6-Pentabromophenylacetate

    Anne M. Sauer

    2010-08-01

    Full Text Available The title compound PBPEA, C10H7Br5O2, has its ethyl acetate portion nearly orthogonal to the benzene ring, with a CCCC torsion angle of 88.3?(5. The packing involves an intermolecular contact with a Br...Br distance of 3.491?(1?, having CBr...Br angles of 173.4?(2 and 106.0?(2. The crystal studied was an inversion twin.

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

    Toluene and m-xylene were rapidly mineralized in an anaerobic laboratory aquifer column operated under continuous-flow conditions with nitrate as an electron acceptor. The oxidation of toluene and m-xylene was coupled with the reduction of nitrate, and mineralization was confirmed by trapping 14CO2 evolved from 14C-ring-labeled substrates. Substrate degradation also took place when nitrous oxide replaced nitrate as an electron acceptor, but decomposition was inhibited in the presence of molecular oxygen or after the substitution of nitrate by nitrite. The m-xylene-adapted microorganisms in the aquifer column degraded toluene, benzaldehyde, benzoate, m-toluylaldehyde, m-toluate, m-cresol, p-cresol, and p-hydroxybenzoate but were unable to metabolize benzene, naphthalene, methylcyclohexane, and 1,3-dimethylcyclohexane. Isotope-dilution experiments suggested benzoate as an intermediate formed during anaerobic toluene metabolism. The finding that the highly water-soluble nitrous oxide served as electron acceptor for the anaerobic mineralization of some aromatic hydrocarbons may offer attractive options for the in situ restoration of polluted aquifers

  5. Ethyl 2-(4-nitrobenzamidobenzoate, a non-merohedral twin

    Sohail Saeed

    2011-02-01

    Full Text Available In the title compound, C16H14N2O5, a non-merohedral twin, the dihedral angle between the mean planes of the two benzene rings is 4.0 (9°. The ethyl group is disordered [0.643 (14 and 0.357 (14 occupancy]. The nitro group is twisted by 16.4 (4° from the mean plane of the benzene ring and the mean plane of the carbonyl group is twisted from the mean planes of the two benzene rings by 4.5 (0 and 4.7 (9°. An intramolecular N—H...O hydrogen bond occurs. The crystal packing is stabilized by weak intermolecular C—H...O hydrogen-bond interactions.

  6. ndicesde refraccin y densidad de mezclas binarias de heptano con ciclohexano, benceno y tolueno a 293.15, 298.15, 303.15 y 308.15 K / Refraction indexes and density for binary mixtures of heptane with cyclohexane, benzene and toluene at 293.15, 298.15, 303.15 K / ndices derefrao e densidade de misturas binrias de heptano com ciclo-hexano, benzenoe tolueno a 293.15, 298.15, 303.15 e 308.15 K

    Marlon D., Martnez-Reina; Eliseo, Amado-Gonzlez.

    2012-06-01

    Full Text Available Determinam-sedensidades e ndices de refrao de misturas binrias de ciclo-hexano, benzenoe tolueno com heptano a (293.15, 298.15, 303.15 e 308.15) K. Se calcularem osvolumes de excesso molar e o cambio do ndice de refrao (??D) a partir dosdados experimentais e ajustados uma equao polinomial [...] de Redlich-Kister deordem quatro. Abstract in spanish Semidieron densidades e ndices de refraccin de mezclas binarias de ciclohexano,benceno y tolueno con heptano a (293.15, 298.15, 303.15 y 308.15) K. El volumende exceso molar y el cambio de ndice de refraccin (??D) son calculados desdelos datos experimentales y ajustados con una ecuacin polinomi [...] al deRedlich-Kister de orden cuatro. Abstract in english Density and refraction indexes forbinary mixtures of cyclohexane, benzene and toluene with heptane (293.15, 298.15,303.15 and 308.15 K) were measured. Excess molar volume and refraction indexchange (??D) werecalculated from experimental data and adjusted with a fourth-orderRedlich-Kister polynomial [...] equation.

  7. Thermodynamics of mixtures involving some (benzene derivatives+benzonitrile)

    Interactions of binary mixtures involving some benzene derivatives (ethylbenzene, o-, m-, p-xylene, isopropylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, and methoxybenzene) with benzonitrile were investigated in continuation of our previous studies on binary systems (benzene or toluene+benzonitrile). Heat capacities by volume unit, determined with a Picker flow calorimeter at T=298.15K, and densities, measured by using Picker vibrating densimeters at the temperatures (298.15 and 308.15)K, are reported. Measurements were made over the entire range of mole fraction. From the primary measurements, the corresponding excess quantities VE and Cp,mE are obtained. The magnitude of these experimental quantities together with HE literature data is discussed in terms of the nature and type of intermolecular interactions in binary mixtures

  8. Crystal structure of 4,8-di-tert-butyl-6,6-dichloro-13-ethyl-2,10-dimethyl-13,14-dihydro-12H-dibenzo[d,i][1,3,7,2]dioxazasilecine toluene 0.25-solvate

    Ekaterina A. Kuchuk

    2015-12-01

    Full Text Available The coordination polyhedron at the silicon atom in the title compound, C26H37Cl2NO2Si·0.25C7H8, is typical for pentacoordinated silicon derivatives and represents a slightly distorted trigonal bipyramid with an N atom and a Cl atom in the apical positions and the two O atoms and the other Cl atom occupying the equatorial sites. There are two independent molecules in the asymmetric unit. The N–Si–Cl fragment in each is close to linear [178.24 (5 and 178.71 (5°], in good agreement with 4e–3c theory, as is the elongation of the apical bond lengths [Si—Cl = 2.1663 (7 and 2.1797 (7 Å] in comparison with the equatorial bonds [Si—Cl = 2.0784 (7 and 2.0748 (7 Å]. Orthogonal least-squares fitting of the two independent molecules resulted in r.m.s. deviation of 0.017 Å. The conformations of the two molecules are almost the same, with corresponding torsion angles differing by less than 5.5°. The toluene solvent molecule is disordered about an inversion centre.

  9. Cross-regulation of toluene monooxygenases by the transcriptional activators TbmR and TbuT.

    Leahy, J G; G. R. Johnson; Olsen, R H

    1997-01-01

    The toluene-3-monooxygenase from Burkholderia pickettii PKO1 and the toluene/benzene-2-monooxygenase from Burkholderia (Pseudomonas) sp. strain JS150 are distinct enzymes which differ not only in catalytic specificity and substrate range but also in the arrangement and sequence of the genes within the operons that encode the enzymes, tbuA1UBVA2C and tbmABCDEF, respectively. In the present study, we examined the transcriptional activation of the PtbuA1 and PtbmA promoters by their cognate regu...

  10. Impact of a new gasoline benzene regulation on ambient air pollutants in Anchorage, Alaska

    Yano, Yuriko; Morris, Stephen S.; Salerno, Christopher; Schlapia, Anne M.; Stichick, Mathew

    2016-05-01

    The purpose of this study was to quantify the impact of a new U.S. Environmental Protection Agency (EPA) standard that limits the amount of benzene allowed in gasoline on ambient benzene concentrations. This new standard, together with two companion regulations that limit cold-temperature automotive emissions and the permeability of portable fuel containers, was expected to lower the levels of ambient benzene and other volatile organic compounds (VOCs) nationwide. In this study the impact of the gasoline benzene standard was evaluated in Anchorage, Alaska in a two-phase ambient air monitoring study conducted before and after the new gasoline standard was implemented. Gasoline sold by Anchorage retailers was also evaluated in each phase to determine the content of benzene and other gasoline components. The average benzene content in Anchorage gasoline was reduced by 70%, from 5.05% (w/w) to 1.53% (w/w) following the implementation of the standard. The annual mean ambient benzene concentration fell by 51%, from 0.99 ppbv in Phase 1 to 0.49 ppbv in Phase 2. Analysis suggests the change in gasoline benzene content alone reduced benzene emissions by 46%. The changes in toluene, ethylbenzene, and xylene content in gasoline between Phase 1 and 2 were relatively small and the differences in the mean ambient concentrations of these compounds between phases were modest. Our results suggest that cold winter communities in high latitude and mountainous regions may benefit more from the gasoline benzene standard because of high benzene emissions resulting from vehicle cold start and a tendency to develop atmospheric stagnation conditions in the winter.

  11. Fogging in Polyvinyl Toluene Scintillators

    Cameron, Richard J.; Fritz, Brad G.; Hurlbut, Charles; Kouzes, Richard T.; Ramey, Ashley; Smola, Richard

    2015-02-01

    It has been observed that large polyvinyl toluene (PVT)-based gamma ray detectors can suffer internal “fogging” when exposed to outdoor environmental conditions over long periods of time. When observed, this change results in reduced light collection by photomultiplier tubes connected to the PVT. Investigation of the physical cause of these changes has been explored, and a root cause identified. Water penetration into the PVT from hot, high-humidity conditions results in reversible internal water condensation at room temperature, and permanent micro-fracturing of the PVT at very low environmental temperatures. Mitigation procedures and methods are being investigated.

  12. Toluene pyrolysis studies and high temperature reactions of propargyl chloride

    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.

  13. Determination of conformational and spectroscopic features of ethyl trans-alfa-cyano-3-indole-acrylate compound: an experimental and quantum chemical study.

    Cinar, Mehmet; Karabacak, Mehmet

    2013-03-01

    The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and non-linear optical properties of ethyl trans-alfa-cyano-3-indole-acrylate (C(14)H(12)N(2)O(2)) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman in the range of 4000-400 cm(-1) and 4000-10 cm(-1), respectively. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The (1)H, (13)C and DEPT NMR spectra were recorded in DMSO solution, and gauge-invariant atomic orbitals (GIAO) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were recorded in the range of 200-800 nm in various solvents of different polarity (acetone, benzene, chlorobenzene, chloroform, DMSO, ethanol, methanol and toluene). Solvent effects were calculated using TD-DFT and CIS method. To investigate the non-linear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations. PMID:23274474

  14. N-[(E)-(9-Ethyl-9H-carbazol-3-yl)methylidene]aniline

    Nuray Yeksan; Ece Uzkara; Orhan Zeybek; Erol Asker

    2010-01-01

    The title compound, C21H18N2, was obtained as the product of the reaction between 9-ethyl-9H-carbazole-3-carbaldehyde and aniline in ethanol. The crystal packing is stabilized mainly by CH...? interactions between the carbazole benzene rings and the methylene H atoms.

  15. N-[(E-(9-Ethyl-9H-carbazol-3-ylmethylidene]aniline

    Nuray Yeksan

    2010-06-01

    Full Text Available The title compound, C21H18N2, was obtained as the product of the reaction between 9-ethyl-9H-carbazole-3-carbaldehyde and aniline in ethanol. The crystal packing is stabilized mainly by CH...? interactions between the carbazole benzene rings and the methylene H atoms.

  16. Benzene vapor recovery and processing

    The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, have provided a powerful motivation for interest in, and attention to, benzene vapor emissions in recent times. Benzene and its related aromatics are volatile organic compounds (VOCs), which marks them for surveillance as potential contributors to air pollution. In addition, benzene is a suspected carcinogen, which applies a special urgency to its control. The regulations governing the control of benzene emissions were issued as Title 40, Code of Federal Regulations, Part 61, subpart Y (Storage Vessels); subpart BB (Transfer Operations); and subpart FF (Waste Operations). These regulations specify very particular emission reduction guidelines for various generating sources. The problem in the hydrocarbon processing industry is to identify significant sources of benzene vapors in plants, and then to collect and process these vapors in an environmentally acceptable manner. This paper discusses various methods for collecting benzene fumes in these facilities

  17. Toluene depresses plasma corticosterone in pregnant rats

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

    2003-01-01

    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...

  18. Toluene depresses plasma corticosterone in pregnant rats

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

    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 ...

  19. Benzene exposures in urban areas

    Benzene exposures in urban areas were reviewed. Available data confirm that both in USA and Europe, benzene concentrations measured by fixed outdoor monitoring stations underestimate personal exposures of urban residents. Indoor sources, passive smoke and the high exposures during commuting time may explain this difference. Measures in European towns confirm that very frequently mean daily personal exposures to benzene exceed 10 μg/m3, current European air quality guideline for this carcinogenic compound

  20. Biomarkers of environmental benzene exposure.

    Weisel, C; Yu, R; Roy, A; Georgopoulos, P.

    1996-01-01

    Environmental exposures to benzene result in increases in body burden that are reflected in various biomarkers of exposure, including benzene in exhaled breath, benzene in blood and urinary trans-trans-muconic acid and S-phenylmercapturic acid. A review of the literature indicates that these biomarkers can be used to distinguish populations with different levels of exposure (such as smokers from nonsmokers and occupationally exposed from environmentally exposed populations) and to determine d...

  1. Are biogenic emissions a significant source of summertime atmospheric toluene in the rural Northeastern United States?

    M. L. White

    2009-01-01

    Full Text Available Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequently, three hydrocarbon sources were investigated for potential contributions to the enhancements during 20042006. These included: (1 increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG content to meet US EPA summertime volatility standards, (2 local industrial emissions and (3 local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d?1, and did not fully account for the observed enhancements (2050 pptv in 20042006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d?1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d?1 and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  2. Are biogenic emissions a significant source of summertime atmospheric toluene in rural Northeastern United States?

    M. L. White

    2008-06-01

    Full Text Available Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequentially, three hydrocarbon sources were investigated for potential contributions to the enhancements during 20042006. These included: 1 increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG content to meet U.S. EPA summertime volatility standards, 2 local industrial emissions and 3 local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d?1, and did not fully account for the observed enhancements (2050 pptv in 20042006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d?1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d?1 and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  3. Quaternary (liquid + liquid) equilibrium data for the extraction of toluene from alkanes using the ionic liquid [EMim][MSO4

    Highlights: • EMim[MSO4] was proposed as solvent for the extraction of toluene from alkanes. • The quaternary system {heptane + cyclohexane + toluene + [EMim][MSO4]} was evaluated. • The extraction of toluene would be facilitated in the presence of one alkane. • Experimental LLE data were successfully correlated with the NRTL model. - Abstract: (Liquid + liquid) equilibrium (LLE) studies for the extraction of aromatics from alkanes present in the petroleum fractions are important to develop theoretical/semiempirical (liquid + liquid) equilibrium models, which are used in the design of extraction processes. In this work, the ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO4], was evaluated as potential solvent for the separation of toluene from heptane and cyclohexane. The LLE data for the quaternary system {heptane (1) + cyclohexane (2) + toluene (3) + [EMim][MSO4] (4)} were experimentally determined at T = 298.15 K and atmospheric pressure. Moreover, the LLE data for the ternary systems {heptane or cyclohexane (1) + toluene (2) + [EMim][MSO4] (3)} were also determined. Solute distribution ratios and selectivities were calculated and analysed in order to evaluate the capability of the ionic liquid to accomplish the separation target. A comparison between the solute distribution ratios and selectivities for the quaternary and the ternary systems was also made. Finally, the experimental tie-line data were correlated with the NRTL model

  4. In situ transformation of deuterated toluene and xylene to benzylsuccinic acid analogues in BTEX-contaminated aquifers.

    Reusser, D E; Istok, J D; Beller, H R; Field, J A

    2002-10-01

    Techniques for detecting and quantifying anaerobic transformations of benzene, toluene, ethylbenzene, and xylene (BTEX) are needed to assess the feasibility of using in situ bioremediation to treat BTEX-contaminated groundwater aquifers. Deuterated surrogates of toluene (toluene-d8) and xylene (o-xylene-d10) were injected into BTEX-contaminated aquifers during single-well push-pull tests to monitor for the in situ formation of deuterated benzylsuccinic acid (BSA-d8) and o-methyl-BSA-d10. Test solutions (250 L) containing toluene-d8 (9-22 microM) and o-xylene-d10 (4-9 microM) along with a conservative bromide tracer (1.3 mM) and nitrate (4 mM) as an electron acceptor were injected into four wells at two sites. Detection of BSA-d8 and o-methyl-BSA-d10 in groundwater samples collected from the same wells following injection unequivocally demonstrated anaerobic in situ toluene-d8 and o-xylene-d10 transformation with calculated zero-order formation rates ranging from 1.0 to 7.4 nM/day. Concurrent utilization of co-injected nitrate was rapid in all tests at both sites, with zero-order rates ranging from 13 to 39 microM/h. The field tests conducted in this study represent the first reported use of deuterated aromatic hydrocarbons to detect and quantify anaerobic BTEX transformation product formation in the subsurface. PMID:12380085

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

    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

  6. Ambient air benzene at background sites in China's most developed coastal regions: exposure levels, source implications and health risks.

    Zhang, Zhou; Wang, Xinming; Zhang, Yanli; Lü, Sujun; Huang, Zhonghui; Huang, Xinyu; Wang, Yuesi

    2015-04-01

    Benzene is a known human carcinogen causing leukemia, yet ambient air quality objectives for benzene are not available in China. The ambient benzene levels at four background sites in China's most developed coastal regions were measured from March 2012 to February 2013. The sites are: SYNECP, in the Northeast China Plain (NECP); YCNCP, in the North China Plain (NCP); THYRD, in the Yangtze River Delta (YRD) and DHPRD, in the Pearl River Delta (PRD). It was found that the mean annual benzene levels (578-1297 ppt) at the background sites were alarmingly higher, especially when compared to those of 60-480 pptv monitored in 28 cities in the United States. Wintertime benzene levels were significantly elevated at both sites (SYNECP and YCNCP) in northern China due to heating with coal/biofuels. Even at these background sites, the lifetime cancer risks of benzene (1.7-3.7E-05) all exceeded 1E-06 set by USEPA as acceptable for adults. At both sites in northern China, good correlations between benzene and CO or chloromethane, together with much lower toluene/benzene (T/B) ratios, suggested that benzene was largely related to coal combustion and biomass/biofuel burning. At the DHPRD site in the PRD, benzene revealed a highly significant correlation with methyl tert-butyl ether (MTBE), indicating that its source was predominantly from vehicle emissions. At the THYRD site in the YRD, higher T/B ratios and correlations between benzene and tetrachloroethylene, or MTBE, implied that benzene levels were probably affected by both traffic-related and industrial emissions. PMID:25618820

  7. Fuel Dependence of Benzene Pathways

    Zhang, H; Eddings, E; Sarofim, A; Westbrook, C

    2008-07-14

    The relative importance of formation pathways for benzene, an important precursor to soot formation, was determined from the simulation of 22 premixed flames for a wide range of equivalence ratios (1.0 to 3.06), fuels (C{sub 1}-C{sub 12}), and pressures (20 to 760 torr). The maximum benzene concentrations in 15 out of these flames were well reproduced within 30% of the experimental data. Fuel structural properties were found to be critical for benzene production. Cyclohexanes and C{sub 3} and C{sub 4} fuels were found to be among the most productive in benzene formation; and long-chain normal paraffins produce the least amount of benzene. Other properties, such as equivalence ratio and combustion temperatures, were also found to be important in determining the amount of benzene produced in flames. Reaction pathways for benzene formation were examined critically in four premixed flames of structurally different fuels of acetylene, n-decane, butadiene, and cyclohexane. Reactions involving precursors, such as C{sub 3} and C{sub 4} species, were examined. Combination reactions of C{sub 3} species were identified to be the major benzene formation routes with the exception of the cyclohexane flame, in which benzene is formed exclusively from cascading fuel dehydrogenation via cyclohexene and cyclohexadiene intermediates. Acetylene addition makes a minor contribution to benzene formation, except in the butadiene flame where C{sub 4}H{sub 5} radicals are produced directly from the fuel, and in the n-decane flame where C{sub 4}H{sub 5} radicals are produced from large alkyl radical decomposition and H atom abstraction from the resulting large olefins.

  8. Methane from benzene in argon dielectric barrier discharge

    Highlights: ► Efficient on-line conversion of benzene to methane at room temperature. ► Absence of other H-atom donor suggests new type of chemistry. ► For parent loss > 90%, methane yield was ∼40% of limit due to H-atom availability. ► Surface moisture contributed ·OH radical for trace phenolic products’ formation. ► This method may emerge as an exploitable tactic for pollutants’ usable alterations. -- Abstract: A first-time account of direct, on-line, instantaneous and efficient chemical conversion of gas phase benzene to methane in argon Dielectric Barrier Discharge (DBD) is presented. In the absence of another overt hydrogen-donating source, potency of analogous parents toward methane generation is found to follow the order: benzene > toluene > p-xylene. Simultaneous production of trace amounts of phenolic surface deposits suggest (a) prompt decomposition of the parent molecules, including a large fraction yielding atomic transients (H-atom), (b) continuous and appropriate recombination of such parts, and (c) trace moisture in parent contributing ·OH radicals and additional H-atoms, which suitably react with the unreacted fraction of the parent, and also other intermediates. Results highlight Ar DBD to be a simple and exploitable technology for transforming undesirable hazardous aromatics to usable/useful low molecular weight open-chain products following the principles of green chemistry and engineering

  9. Primary atmospheric oxidation mechanism for toluene.

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

    2009-01-01

    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. PMID:19118482

  10. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    OLIVIA ANCA RUSU; CRISTINA NEAGU; IRINA DUMITRASCU; IULIA NEAMTIU; ALEXANDRU ZEIC; EUGEN GURZAU

    2011-01-01

    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 incr...

  11. Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate

    Highlights: ► Measurements of activity coefficients at infinite dilution using GLC. ► Forty-two organic solvents and water in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate. ► High selectivity for heptane/thiophene. ► Possible entrainer for different separation processes with water. ► The excess thermodynamic functions and the gas–liquid partition coefficients were calculated. - Abstract: The activity coefficients at infinite dilution, γ13∞, for 43 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine, and 1-nitropropane in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][MeSO3] were determined by gas–liquid chromatography at six temperatures within the range (308.15 to 358.15) K. The interaction of these 42 organic compounds and water with the ionic liquid were described with the partial molar excess Gibbs free energy, ΔG1E,∞, enthalpy ΔH1E,∞, and entropy TrefΔS1E,∞ at infinite dilution, calculated from the experimental γ13∞ values obtained over the temperature range. The gas–liquid partition coefficients, KL were calculated for all solutes. The values of the selectivity for few separation problems as heptane/toluene, cyclohexane/benzene, heptane/xylenes and heptane/thiophene were calculated from γ13∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [EMIM]+ cation. Comparison with the results published earlier for [EMIM][MeSO3] show much lower selectivities in the discussed separation problems. By contrast with the former measured ILs [EMIM][MeSO3] reveals the average selectivity for the separation of aromatics/aliphatics and low capacity for benzene. An interesting high value of selectivity was observed in the separation of thiophene/aliphatics. Very high values of selectivity may be expected in the separation of the azeotropic systems including water. The density of [EMIM][MeSO3] within temperature range from (298.15 to 358.15) K was measured and compared to the literature values.

  12. Determination of (BTEX) of the gasoline's combustion in Ecuador

    The contents of benzene, toluene, ethyl benzene and xylenes (BTEX) were determined and quantified in the gasoline's combustion on an internal combustion engine. Gas chromatography with flame ionization detector were used for chemical determinations

  13. Construction and comparison of fluorescence and bioluminescence bacterial biosensors for the detection of bioavailable toluene and related compounds

    Environmental pollution with petroleum products such as benzene, toluene, ethylbenzene, and xylenes (BTEX) has garnered increasing awareness because of its serious consequences for human health and the environment. We have constructed toluene bacterial biosensors comprised of two reporter genes, gfp and luxCDABE, characterized by green fluorescence and luminescence, respectively, and compared their abilities to detect bioavailable toluene and related compounds. The bacterial luminescence biosensor allowed faster and more-sensitive detection of toluene; the fluorescence biosensor strain was much more stable and thus more applicable for long-term exposure. Both luminescence and fluorescence biosensors were field-tested to measure the relative bioavailability of BTEX in contaminated groundwater and soil samples. The estimated BTEX concentrations determined by the luminescence and fluorescence bacterial biosensors were closely comparable to each other. Our results demonstrate that both bacterial luminescence and fluorescence biosensors are useful in determining the presence and the bioavailable fractions of BTEX in the environment. - The choice of reporter genes for toluene bacterial biosensors to determine BTEX bioavailability is case-specific

  14. Comparative Study Between Ethylbenzene Disproportionation Reaction and its Ethylation Reaction with Ethanol over ZSM-5

    Tukur, N. M.

    2009-06-23

    Ethylation of ethylbenzene with ethanol has been studied over ZSM-5 catalyst in a riser simulator that mimics the operation of a fluidized-bed reactor. The feed molar ratio of ethylbenzene:ethanol is 1:1. The study was carried out at 350, 400, 450, and 500°C for reaction times of 3, 5, 7, 10, 13, and 15 s. Comparisons are made between the results of the ethylbenzene ethylation reaction with that of ethylbenzene disproportionation reaction earlier reported. The effect of reaction conditions on ethylbenzene reactivity, p-diethylbenzene selectivity, total diethylbenzene (DEB) isomers selectivity, p-DEB-to-m-DEB ratio, benzene-to-DEB molar ratio, and benzene selectivity, are reported. Benzene selectivity is about 10 times more in the EB disproportion reaction as compared to its ethylation reaction with ethanol at 350°C. In addition, the results showed a p-DEB/m-DEB ratio for the EB ethylation reaction varying between 1.2-1.7, which is greater than the equilibrium values. Increase in temperature shifts the alkylation/dealkylation equilibrium towards dealkylation, thereby decreasing conversion and selectivity to DEB. © Springer Science+Business Media, LLC 2009.

  15. Study of the rearrangement of N-alkylaniline to p-aminoalkylbencene. I. N-ethyl-l-14C-aniline

    The rearrangement of N-ethylaniline to p-aminoethylbenzene has been studied over the temperature range 200-300 degree centigrade using different catalysts: Cl2Co, Cl2Zn, Cl2Ni, Cl3Al, Cl2Cd and Br H.N-ethyl-1-14C-aniline has been synthesized from ethyl-1-14C-iodide and aniline and its rearrangement to p-aminoethyl-benzene proves that the ethyl group does not rearrange itself during the reaction. A scheme for the degradation of both the N-ethyl-1-14C aniline and the p-aminoethylbenzene produces is described. (Author) 14 refs

  16. Reactions of 9-Alkyl-3-aminocarbazoles with Ethyl-3-oxo-butanoate and Identification of the Products Obtained

    Gema Mikulskiene

    2006-01-01

    Full Text Available The reactions in benzene of 9-alkyl-3-aminocarbazoles with ethyl-3-oxobutanoateyielded ethyl-3-[(9-alkyl-9H-carbazol-3-ylamino]but-2-enoate condensation products or N-(9-ethyl-9H-carbazol-3-yl-3-oxobutanamide acylation products. The condensation productswere cyclized to the corresponding 4,7-dihydro-pyrido[2,3-c]-carbazol-1-ones upon heatingin mineral oil at 240-250 °C. The structures of the synthesized compounds were investigatedby IR, mass spectrometry, 1H- and 13C-NMR spectroscopy and MM2 molecular mechanicsand AM1 semi-empirical quantum mechanical methods.

  17. Reactions of 9-Alkyl-3-aminocarbazoles with Ethyl-3-oxo-butanoate and Identification of the Products Obtained

    Gema Mikulskiene; ytautas Mickevicius; Birute Sapijanskaite

    2006-01-01

    The reactions in benzene of 9-alkyl-3-aminocarbazoles with ethyl-3-oxobutanoateyielded ethyl-3-[(9-alkyl-9H-carbazol-3-yl)amino]but-2-enoate condensation products or N-(9-ethyl-9H-carbazol-3-yl)-3-oxobutanamide acylation products. The condensation productswere cyclized to the corresponding 4,7-dihydro-pyrido[2,3-c]-carbazol-1-ones upon heatingin mineral oil at 240-250 °C. The structures of the synthesized compounds were investigatedby IR, mass spectrometry, 1H- and 13C-NMR spectroscopy and...

  18. Law and regulation of benzene.

    Feitshans, I L

    1989-01-01

    OSHA has created final benzene regulations after extensive rulemakings on two occasions, 1978 and 1987. These standards have been the subject of extensive litigation for nearly 20 years. This article examines in detail the conceptual underpinnings of the Benzene Case, (which was decided by the U.S. Supreme Court in 1980) in light of U.S. administrative law precedents that have set limits upon administrative discretion under the test for "substantial evidence" and the "hard look doctrine." Thi...

  19. 1-Benzyl-5-ethyl-5-hydroxy-1H-pyrrol-2(5H-one

    Yan-Jiao Gao

    2013-07-01

    Full Text Available The title compound, C13H15NO2, was obtained as a by-product in the Grignard reaction of malimide. The dihedral angle between the five-memebred ring (r.m.s. deviation = 0.005? and the benzene ring is 67.20?(14. The benzene ring and the ethyl chain lie to the same side of the five-membered ring. In the crystal, molecules are linked by OH...O hydrogen bonds, generating C(6 chains propagating in [010].

  20. Role of charge transfer and spin-orbit coupling in fluorescence quenching : a case study with oxonine and substituted benzenes

    Föll, Rudolf E.; Kramer, Horst E.A.; Steiner, Ulrich

    1990-01-01

    Fluorescence quenching of oxonine in methanol was investigated by means of a computerized dye laser flash spectrometer for the ∆G°et, dependence of the quenching rate constant (kq) and the efficiencies of induced dye triplet formation (ηT), reduced dye radical formation (ηR), and induced internal conversion. A total of 34 substituted benzenes including 20 monohalogenated benzenes, toluenes, and anisoles were used as quenchers spanning a range of -0.85 ≤ ∆G°et ≤ 1.4 eV for a possible photoelec...

  1. Ethyl 4,4''-Dibromo-5'-(butylamino-2',6'-dinitro-[1,1':3',1''-terphenyl]-4'-carboxylate

    Damiano Rocchi

    2015-03-01

    Full Text Available Ethyl 4,4''-Dibromo-5'-(butylamino-2',6'-dinitro-[1,1':3',1''-terphenyl]-4'-carboxylate (2 which is a m-terphenyl derivative containing an hexasubstituted, highly functionalized substituted benzene core, has been synthesized.

  2. (E,E,E)-1.3.5-Tris[4-acetylsulfanyl)-styryl]benzene toluene hemisolvate

    Sørensen, H.O.; Magnussen, M.; Stuhr-Hansen, N.

    The first crystal structure of a three-terminal sulfur end-capped oligophenylenevinylene, C36H30O3S3 x 0.5C7H8, has been determined at 122 (1) K. The molecular threefold symmetry is not utilized in the crystal structure. It is confirmed that the double bonds have been fully transformed into a tra...

  3. Ruthenium Nanoparticles Intercalated in Hectorite: A Reusable Hydrogenation Catalyst for Benzene and Toluene

    Sss-Fink, Georg; Mollwitz, Birgit; Therrien, Bruno; Dadras, Massoud; Laurenczy, Gabor; Meister, Annette; Meister, Gtz

    2009-01-01

    The cationic organometallic aqua complexes formed by hydrolysis of [(C6H6)RuCl2]2 in water, mainly [(C6H6)Ru(H2O)3]2+, intercalate into sodium hectorite by ion exchange, replacing the sodium cations between the anionic silicate layers. The yellow hectorite thus obtained reacts in ethanol with molecular hydrogen (50 bar, 100C) with decomposition of the organometallic aqua complexes to give a black material, in which ruthenium(0) nanoparticles (918 nm) are intercalated between the anionic sil...

  4. CFD SIMULATIONS OF BENZENETOLUENE SYSTEM OVER SIEVE TRAY

    Sumit Singh

    2012-08-01

    Full Text Available High degree of competitiveness associated with petroleum leads to the exhaustive search for new technologies that enable greater efficiency in the related processes. A three-dimensional mathematical homogeneous biphasic model was implemented in the commercial code of computational fluid dynamics (CFD, FLUENT package to predict concentration and temperature distributions on sieve trays of distillation columns and good simulation results are obtained. The tray geometries and operating conditions are based on the experimental works of Indian oil corporation limited(R & D. The dispersed gas phase and continuous liquid phase are modelled in the Mixture model for two interpenetrating phases with inter phase momentum, heat and mass transfer. The main objective of this study has been to find the extent to which CFD can be used as a prediction tool for real behaviour, and concentration and temperature distributions of sieve trays. The simulation results are shown that CFD is a powerful tool in tray design, analysis and trouble shooting, and can be considered as a new approach for efficiency calculations.

  5. Evaluation of genotoxic effects of benzene and its derivatives in workers of gas stations.

    Trevisan, Patrcia; da Silva, Juliane Nascimento; da Silva, Alessandra Pawelec; Rosa, Rafael Fabiano Machado; Paskulin, Giorgio Adriano; Thiesen, Flvia Vallado; de Oliveira, Ceres Andria Vieira; Zen, Paulo Ricardo Gazzola

    2014-04-01

    The search for reliable biomarkers of human exposure to benzene and its derivatives is still subject of research. Many of the proposed biomarkers have limitations ranging from the low sensitivity to the wide variability of results. Thus, the aim of our study was to assess the frequencies of chromosomal abnormalities (CA) and sister chromatid exchanges (SCE) in workers of gas stations, with (cases, n?=?19) and without (local controls, n?=?6) risk of exposure to benzene and its derivatives, comparing them with the results from the general population (external controls, n?=?38). The blood dosages of benzene, toluene, and xylenes were measured in all participants. Blood solvent levels were compared with the findings obtained in cytogenetic evaluation and a research protocol which included data of the workplace, lifestyle, and health of the individuals. We did not detect the presence of benzene and its derivatives and did not find chromosomal damage that may be associated with the gas station activity in cases. Moreover, although we found an association of increased SCE and the working time in the local controls, the values found for SCE are within normal limits. Thus, our evaluation of SCE and CA reflected the levels of benzene and its derivatives observed in the blood. We believe, therefore, that SCE and CA may actually constitute possible tests for the evaluation of these exposures. However, we believe that further studies, including individuals at risk, are important to confirm this assertion. PMID:24292950

  6. Catalytic Combustion of Ethyl Acetate

    ÖZÇELİK, Tuğba GÜRMEN; ATALAY, Süheyda; ALPAY, Erden

    2007-01-01

    The catalytic combustion of ethyl acetate over prepared metal oxide catalysts was investigated. CeO, Co2O3, Mn2O3, Cr2O3, and CeO-Co2O3 catalysts were prepared on monolith supports and they were tested. Before conducting the catalyst experiments, we searched for the homogeneous gas phase combustion reaction of ethyl acetate. According to the homogeneous phase experimental results, 45% of ethyl acetate was converted at the maximum reactor temperature tested (350 °C). All the prepare...

  7. Modelling and Simulation Of Benzene Alkylation Process Reactors For Production Of Ethylbenzene

    Majid Kakavand

    2004-10-01

    Full Text Available The goal of this paper is to develop a simulation software for the ethyl benzene production unit in aPetrochemical Complex of Iran. Ethyl benzene whose consumption has rapidly increased in recent years, isthe feed for production of styrene monomer. This material is produced from alkylation of benzene withethylene. A process simulator can play a very important role in the development of this process. In thisresearch, alkylation of benzene for production of ethylbenzene has been simulated. First the mass, energyand momentum balance equations have been developed for the axial flow reactor. Optimization techniqueshave then been applied to modify the kinetic equations presented in literature to somehow satisfy the unitconditions. Finally the model predicted values such as pressure, reactor temperature, reactant conversionand products compositions have been compared with those of experimental ones adopted from theindustrial unit. The comparison reveals that the model predicted values are adequately in compliance withthe experimental data and hence can be used, with sufficient accuracy, to design pilot plants and other newunits.

  8. Ethyl 2,4-dimethylpyrido[1,2-a]benzimidazole-3-carboxylate

    Ai Guo Zhu

    2012-10-01

    Full Text Available The title compound, C16H16N2O2, was synthesized using a novel tandem annulation reaction between 1-(1H-benzo[d]imidazol-2-ylethanone and ethyl (E-4-bromobut-2-enoate under mild conditions. The dihedral angles formed by the mean plane of the five-membered imidazole ring with the dihydropyridin and benzene rings are 1.54?(9 and 1.85?(9, respectively.

  9. Diffusion and adsorption of benzene in Regina clay

    Surface or near-surface spills of hydrocarbons such as gasoline and diesel often occur in clay soils which are fractured and unsaturated. For cost-effective remediation, the extent of contamination and the distribution of the various phases should be determined before the development of remediation methods. The four volatile compounds that are commonly associated with gasoline leaking from underground fuel storage tanks are benzene, toluene, ethlybenzene and xylene. Existing diffusion test methods have been used successfully for inorganic species, but the successful application of these methods to volatile organic compounds is limited. The main difficulty with experiments using volatile organics is that there is a need for careful sample handling and sensitive analytical methods to accurately measure the aqueous concentration. Work was carried out to develop an apparatus that could be used to measure the diffusion and adsorption of volatile organics in clay. The best visual fit to the experimental data for the single reservoir test was an effective diffusion coefficient of 0.01 mL/g, and an adsorption coefficient of 0.1 mL/g. Based on diffusion cell tests, there are relatively low levels of retardation for benzene as it moves in clay soils with low organic carbon content. The implications for remediation are summarized. 28 refs., 16 figs., 5 tabs

  10. Human response to varying concentrations of toluene

    Bælum, Jesper; Lundqvist, G R; Mølhave, Lars; Andersen, N T

    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...

  11. Toluene Induces Depression-Like Behaviors in Adult Mice

    Yang, Miyoung; Kim, Sung-Ho; KIM, Jong-Choon; Shin, Taekyun; Moon, Changjong

    2010-01-01

    It has been clinically reported that toluene causes mental depression in humans. However, the detrimental effects of toluene exposure on brain function and the relation between features of mental depression and toluene exposure are poorly understood. This study evaluated depression-like behaviors in adult C57BL/6 mice after administration of toluene, and elucidated the effects of classical antidepressants on the depression-like behaviors. For the estimation of depression-like behaviors, tail ...

  12. The Solubility of Phenylborate Compounds in Benzene

    The original goal of this scoping study was to determine if the solubility of sodium and potassium tetraphenylborates in benzene was sufficiently large to justify designing and performing kinetic studies on a benzene-phase catalytic reaction

  13. 27 CFR 21.97 - Benzene.

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Benzene. 21.97 Section 21... TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.97 Benzene. (a..., Standard No. D 836-77; for incorporation by reference, see § 21.6(b).) When 100 ml of benzene are...

  14. Gene components responsible for discrete substrate specificity in the metabolism of biphenyl (bph operon) and toluene (tod operon).

    K. Furukawa; J. Hirose; Suyama, A; Zaiki, T; Hayashida, S.

    1993-01-01

    bph operons coding for biphenyl-polychlorinated biphenyl degradation in Pseudomonas pseudoalcaligenes KF707 and Pseudomonas putida KF715 and tod operons coding for toluene-benzene metabolism in P. putida F1 are very similar in gene organization as well as size and homology of the corresponding enzymes (G. J. Zylstra and D. T. Gibson, J. Biol. Chem. 264:14940-14946, 1989; K. Taira, J. Hirose, S. Hayashida, and K. Furukawa, J. Biol. Chem. 267:4844-4853, 1992), despite their discrete substrate r...

  15. Intrazeolite ruthenium(0) nanoclusters: a superb catalyst for the hydrogenation of benzene and the hydrolysis of sodium borohydride.

    Zahmakiran, Mehmet; Ozkar, Saim

    2008-07-15

    The use of microporous materials with ordered porous structures as the hosts to encapsulate metal nanoclusters has attracted particular interest in catalysis because the pore size restriction could limit the growth of nanoclusters and lead to an increase in the percentage of the catalytically active surface atoms. This letter reports the preparation of ruthenium(0) nanoclusters stabilized by the framework of Zeolite-Y by using a simple, easy, efficient method and their superb catalytic activities in two important reactions: the hydrogenation of arenes (benzene, toluene, o-xylene, mesitylene) and the hydrolysis of sodium borohydride, all at room temperature. Particularly, the intrazeolite ruthenium(0) nanoclusters exhibit unprecedented catalytic activity in the hydrogenation of neat benzene at 22.0 +/- 0.1 degrees C and 40 +/- 1 psig H2 with a record TOF of 1040 mol benzene/mol Ru . h. PMID:18547068

  16. Solvent extraction-spectrophotometric determination of boron with 3,5-di-tert-butylcatechol and ethyl violet

    Oshima, M.; Motomizu, S.; Toei, K.

    1984-01-01

    Boric acid and 3,5-di-tert-butylcathechol formed a complex anion at pH 6.3-8.7 which was extracted into toluene as an ion pair with ethyl violet (EV); the excess EV coextracted into toluene was removed by adding 3% hydrogen peroxide. Boron was determined spectrophotometrically by measuring the absorbance of EV of the ion pair in toluene at 610 nm. The calibration curve was linear within a range of 0.043 ..mu..g of boron, and the molar absorptivity was 10.5 x 10/sup 4/ L mol/sup -1/ cm/sup -1/. This method, using the new complexing agent, was applied to the determination of boron in seawater and found to be appreciably satisfactory compared with other methods. 7 references, 3 tables, 2 figures.

  17. 3-[(E-(4-Ethylphenyliminomethyl]benzene-1,2-diol

    Zeynep Keleşoğlu

    2009-08-01

    Full Text Available The title compound, C15H15NO2, adopts the enol–imine tautomeric form. The dihedral angle between the two benzene rings is 48.1 (1°. Intramolecular O—H...N and O—H...O hydrogen bonds generate S(6 and S(5 ring motifs, respectively. In the crystal, molecules are linked into centrosymmetric R22(10 dimers via pairs of O—H...O hydrogen bonds and the dimers may interact through very weak by π–π interactions [centroid–centroid distance = 4.150 (1 Å]. The ethyl group is disordered over two orientations, with occupancies of 0.587 (11 and 0.413 (11.

  18. Role of toluene in hydrogen sulfide combustion under Claus condition

    Highlights: • Examined the role of toluene addition in hydrogen sulfide combustion. • Effect of 0%, 0.5%, 1% and 5% of toluene in H2S gas stream was examined. • Toluene addition triggers production of H2 which provides oxidation competition to H2S. • Increased amount of toluene in H2S gas reduced SO2 and increased asymptotic value of H2S. • Toluene addition enhanced the formation of CO and COS. - Abstract: Experimental investigations on the effect of different amounts of toluene addition to H2S combustion in oxygen under Claus condition (Φ = 3) are presented. Three toluene concentrations of 0.5%, 1% and 5% in H2S are presented and compared with the baseline case of 100% H2S oxygen combustion. Temperature data showed that addition of toluene to H2S gas stream increases the flame temperature because of large heating value associated with toluene. Addition of toluene resulted in the production of H2, which increased with increase in the amounts of toluene addition. Furthermore, increased addition of toluene concentration increased the asymptotic minimum value of hydrogen sulfide due to oxidation competition between the formed H2 and H2S. The results also showed that the presence of CO triggers the formation of COS with toluene addition due to reaction of CO with SO2. The results showed that SO2 mole fraction increased to a maximum value then decayed with distance along the reactor. Addition of toluene increased the rate of SO2 decay. These results have direct impact on sulfur capture in the Claus reactor and its performance

  19. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    2010-10-01

    ... benzene and benzene containing cargoes, or butyl acrylate cargoes. 151.05-2 Section 151.05-2 Shipping... Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or butyl acrylate cargoes. A tank barge certificated to carry benzene and benzene containing cargoes or...

  20. Acylation of Toluene with Isobutyryl Chloride

    Čejka, Jiří; Klisáková, Jana; Žilková, Naděžda; Červený, L.

    Cape Town, 2004 - ( Steen van, E.), s. 2717-2723 ISBN 0-958-46636-X. [International Zeolite Conference /14./. Cape Town (ZA), 25.04.2004-30.04.2004] R&D Projects: GA ČR GA203/03/0804 Institutional research plan: CEZ:AV0Z4040901 Keywords : acylation of toluene * isobutyryl chloride * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry

  1. Developmental toxicity of prenatal exposure to toluene

    Bowen, Scott E; John H. Hannigan

    2006-01-01

    Organic solvents have become ubiquitous in our environment and are essential for industry. Many women of reproductive age are incresingly exposed to solvents such as toluene in occupational settings (ie, long-term, lowconcentration exposures) or through inhalant abuse (eg, episodic, binge exposures to high concentrations). The risk for teratogenic outcome is much less with low to moderate occupational solvent exposure compared with the greater potential for adverse pregnancy outcomes, develop...

  2. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    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. Benzene exposures caused by traffic in Munich public transportation systems between 1993 and 1997

    Roemmelt, H.; Pfaller, A.; Fruhmann, G.; Nowak, D. [Institute and Outpatient Clinic for Occupational and Environmental Medicine, Ludwig-Maximilians-University Munich, Ziemssenstr. 1, D-80336 Munich (Germany)

    1999-10-29

    Volatile aromatics (benzene, toluene, xylenes, the BTX-aromatics) were measured between 1993 and 1997 in buses and trams in Munich center and along main roads during regular rides. The sampling time was between 07.00 and 00.00 h. A total of 631 probes were sampled and centrally analyzed. In the mean of 5 years we found 15.0 {mu}g benzene/m{sup 3}, 50% above the limit of the 23. BImSchV and 107.5 {mu}g BTX aromates/m{sup 3} along the strongly traffic loaded main streets. Splitting up these mean emissions into single years we observed a trend toward a decline of mean immission of all volatile aromatics (benzene from 23.8 {mu}g/m{sup 3} to 7.4 {mu}g/m{sup 3}) and the sum of BTX aromatics (from 147.5 {mu}g/m{sup 3} to 59.4 {mu}g/m{sup 3}). The measured hydrocarbon concentrations in Munich center were consistent with the long range theoretical calculations concerning the decrease of traffic-caused benzene immissions in cities. If the current trends continue, we can expect benzene concentrations to be below 5 {mu}g/m{sup 3} by the year 2001 and below 2.5 {mu}g/m{sup 3} by the year 2008. At these levels, the carcinogenic risk from benzene is probably less significant than the risks to public health from other car exhaust components.

  4. Double photoionization of halogenated benzene

    We have experimentally investigated the double-photoionization process in C6BrF5 using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C6H3D3) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance

  5. Double photoionization of halogenated benzene

    AlKhaldi, Mashaal Q.; Wehlitz, Ralf

    2016-01-01

    We have experimentally investigated the double-photoionization process in C6BrF5 using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C6H3D3) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance.

  6. Hepatic metabolism of toluene after gastrointestinal uptake in humans

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

    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...... exposure to 2 mg.min-1 for 3 h the alveolar toluene concentration was 0.07 (range 0-0.11) mg.m-3; exposure to 6 mg.min-1 for 30 min increased the alveolar concentration to 0.9 (range 0.03-2.6) mg.m-3. Ingestion of 0.08, 0.16, and 0.32 g of ethanol per kilogram of body weight during toluene exposure of 2 mg...... doses of ethanol inhibit toluene metabolism, and the procedure is sensitive enough to measure metabolic interactions between solvents and other xenobiotics in humans....

  7. Toluene mediated oxidative stress and granulo-monocytopoiesis

    Božić Tatjana P.; Stevanović Jelka Ž.; Kovačević Milica M.; Jović Slavoljub Z.; Lukić Sanja; Petakov Marijana D.; Borozan Sunčica Z.; Mijačević Zora M.; Knežević Milijana A.; Bulajić Snežana B.

    2003-01-01

    The influence of toluene exposure on some biochemical and hematological parameters was investigated in adult female Wistar rats. The animals were subjected to intraperitoneal administration of toluene diluted in propylene glycol and the diluent alone for 3, 7 and 11 consecutive days at the same time intervals. The effects of toluene and propylene glycol were evaluated biochemically by determining the plasma concentrations of total proteins albumin and ceruloplasmin (Cp) together with erythroc...

  8. Impact of trichloroethylene and toluene on nitrogen cycling in soil.

    Fuller, M. E.; Scow, K.M.

    1997-01-01

    The effects of trichloroethylene (TCE) and toluene on soil nitrogen-cycling activities were examined. Ammonium oxidation potential (AOP) was reduced after incubation with as little as 1 microgram of TCE ml-1, and the effects were generally greater when toluene was present and increased with longer exposure. Arginine ammonification potential and denitrification enzyme activity were constant regardless of TCE concentration or the presence of toluene, while nitrite oxidation potential (NOP) exhi...

  9. 21 CFR 172.868 - Ethyl cellulose.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl cellulose. 172.868 Section 172.868 Food and... Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is a cellulose...

  10. 21 CFR 573.420 - Ethyl cellulose.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and... Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  11. Low energy elastic scattering from toluene

    Sakaamini, Ahmad; Hargreaves, Leigh; Khakoo, Murtadha A.; Pastega, Diego Farago; Bettega, Marcio H. F.

    2015-09-01

    Differential scattering cross sections for elastic scattering of low-energy electrons from toluene are presented in the form of experimental and theoretical (Schwinger multichannel method with pseudopotentials) results. The experimental incident electron energy range is from 1 eV to 20 eV and scattering angles from 15 to 130 degrees. Comparisons with other available cross sections are also presented. CSUF is funded by an NSF-PHY-RUI grant; U. Federal do Parana is funded by CNPq, CAPES and Finep.

  12. Anaerobic degradation of toluene by a denitrifying bacterium.

    Evans, P J; Mang, D T; Kim, K S; Young, L Y

    1991-01-01

    A denitrifying bacterium, designated strain T1, that grew with toluene as the sole source of carbon under anaerobic conditions was isolated. The type of agar used in solid media and the toxicity of toluene were determinative factors in the successful isolation of strain T1. Greater than 50% of the toluene carbon was oxidized to CO2, and 29% was assimilated into biomass. The oxidation of toluene to CO2 was stoichiometrically coupled to nitrate reduction and denitrification. Strain T1 was tolerant of and grew on 3 mM toluene after a lag phase. The rate of toluene degradation was 1.8 mumol min-1 liter-1 (56 nmol min-1 mg of protein-1) in a cell suspension. Strain T1 was distinct from other bacteria that oxidize toluene anaerobically, but it may utilize a similar biochemical pathway of oxidation. In addition, o-xylene was transformed to a metabolite in the presence of toluene but did not serve as the sole source of carbon for growth of strain T1. This transformation was dependent on the degradation of toluene. Images PMID:2059037

  13. Decomposition of toluene in a gliding arc discharge plasma reactor

    Du Changming [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Yan Jianhua [Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027 (China); Cheron, Bruno [UMR 6614 (CORIA), University of Rouen, 76821 Mont Saint Aignan (France)

    2007-11-15

    The decomposition of toluene in a gliding arc discharge (glidarc) was performed and studied. Experimental results indicate that the glidarc technology can effectively decompose toluene molecules and has bright prospects of being applied as an alternative tool to decompose volatile organic compounds. It is found that a change in the electrode material had an insignificant effect on the toluene removal efficiency. The toluene removal efficiency increases with increasing inlet gas temperature. The water vapor present in the gas mixture has a favorable effect on the toluene decomposition in the plasma. The energy efficiency is 29.46 g (kWh{sup -1}) at a relative humidity of 50% and a specific energy input of 0.26 kWh m{sup -3}, which is higher than other types of non-thermal plasmas. Too much or too little oxygen content does not favor toluene decomposition. The major gas phase products detected by FT-IR from the decomposition of toluene with air participation were CO, CO{sub 2}, H{sub 2}O and NO{sub 2}. Some brown depositions were found on the surface of the electrodes, which were polar oxygenous and nitrogenous compounds determined by the GC-MS analysis, such as benzaldehyde, benzoic acid, quinine and nitrophenol from the reaction of toluene with radicals. A possible mechanism for toluene destruction via glidarc technology is proposed and summarized.

  14. Production of Phenol from Benzene via Cumene

    Daniels, D. J.; And Others

    1976-01-01

    Describes an undergraduate chemistry laboratory experiment involving the production of phenol from benzene with the intermediate production of isopropylbenzene and isopropylbenzene hydroperoxide. (SL)

  15. Evaluation of the performance of a passive sampler in the monitoring of benzene and other volatile aromatic compounds in urban and indoor sites

    Laboratory and field tests have been performed on a new passive device, properly designed for the collection of volatile organic compounds from ambient air on an active charcoal layer. Tests performed in order to determine accuracy and precision, response linearity and employment limits show that this device may be helpful in long and medium-time determinations of BTX (benzene, toluene and xylenes) in the atmosphere. The sampler is optimised for a four weeks sampling in open air

  16. Natureza do coque formado sobre a mordenita durante a transalquilação de benzeno Nature of the coke formed on mordenite during benzene transalkylation

    Maria do Carmo Rangel; Antoninho Valentini; Adriana Santana de Oliveira; Jorge Maurício David; Jaildes Marques Britto; Suzana Marques Domingues; Patrício Reyes

    2003-01-01

    Zeolite catalysts have been extensively used in petroleum refining and the chemical industry although they are deactivated by coke deposition. In order to find the best condition to avoid deactivation, the coke formation on H-mordenite was studied in this work. The coke was produced during benzene transalkylation with C9+ aromatics, under several reaction conditions. It was found that hydrogenated coke was produced in all samples without affecting the selectivity of toluene and xylene formati...

  17. Albumin Adducts of Electrophilic Benzene Metabolites in Benzene-Exposed and Control Workers

    Lin, Yu-Sheng; Vermeulen, Roel; Tsai, Chin H.; Waidyanatha, Suramya; Lan, Qing; Rothman, Nathaniel; Smith, Martyn T; Zhang, Luoping; Shen, Min; Li, Guilan; Yin, Songnian; Kim, Sungkyoon; Rappaport, Stephen M.

    2006-01-01

    Background Metabolism of benzene produces reactive electrophiles, including benzene oxide (BO), 1,4-benzoquinone (1,4-BQ), and 1,2-benzoquinone (1,2-BQ), that are capable of reacting with blood proteins to produce adducts. Objectives The main purpose of this study was to characterize relationships between levels of albumin adducts of these electrophiles in blood and the corresponding benzene exposures in benzene-exposed and control workers, after adjusting for important covariates. Because se...

  18. Excess parameter studies on the binary mixtures of toluene with ketones at different temperatures

    Density, ?, ultrasonic speed, u, and viscosity, ? of binary mixtures of toluene with acetone (AC), ethyl methyl ketone (EMK), and acetophenone (AP), including those of pure liquids are measured over the entire composition range at temperatures (298.15, 303.15, and 308.15) K respectively. From these experimental results, deviations in isentropic compressibility, ?ks and ultrasonic speed, ?u, excess intermolecular free length, LfE, excess Gibbs free energy of activation, ?G*E, partial molar volumes (V-barm,10,V-barm,20,V-bar?,10,V-bar?,20) partial molar compressibilities (K-barm,10,K-barm,20,K-bar?,10, and K-bar?,20) and their excess values (V-barm,10E,V-barm,20E,V-bar?,10E,V-bar?,20E,K-barm,10E,K-barm,20E, K-bar?,10E, and K-bar?,20E) of the components at infinite dilution are calculated. The values of ?ks and LfE are found to be negative, and those of ?u and ?G*E are found to be positive, indicating the presence of specific interactions between toluene and ketone molecules and the interactions follow the order: AC > EMK > AP.

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

    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)

  20. Examination on colour reaction of nicotinic acid-ethyl violet-uranyl ternary complex by solvent extraction spectrophotometry

    The test examination was made on solvent extraction colour reaction of the ternary complex formed by nicotinic acid, ethyl violet and uranyl in cyclohexane+MIBK (methyl isobutyl ketone) or benzene+MIBK. A difference was found between the published results and the authors'. It was shown that there is no chromomagnetic dependence with uranyl ion, but the approximate linear correlation is present with NO3- ion

  1. Mechanistic considerations in benzene physiological model development

    Medinsky, M.A.; Kenyon, E.M.; Seaton, M.J.; Schlosser, P.M. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

    1996-12-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Because benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol, and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus the potential exists for competition among various enzymes for phenol. Zonal localization of phase I and phase 11 enzymes in various regions of the liver acinus also impacts this competition. Biologically based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans. 39 refs., 4 figs., 2 tabs.

  2. Transalkylation of ethyl benzene with triethylbenzene over ZSM-5 zeolite catalyst

    Akhtar, M. Naseem

    2010-09-01

    Transalkylation of 1,3,5-triethylbenzene (TEB) with ethylbenzene (EB) has been studied over ZSM-5 zeolite using a riser simulator reactor with respect to optimizing DEB yield. The reaction temperature was varied from 350 to 500°C with contact time ranging from 3 to 15s to report on the effect of reaction conditions on TEB conversion, DEB selectivity and isomerization of TEB. The transalkylation of TEB with EB was compared with the reactions of pure 1,3,5-TEB and EB (disproportionation, isomerization and cracking). A synergistic effect was observed on the conversion of 1,3,5-TEB and DEB yield. The 1,3,5-TEB conversion increased from 40% to 50% with simultaneous increase in the DEB selectivity from 17% to 36% in transalkylation reaction (EB+1,3,5-TEB) as compared with the reaction of pure 1,3,5-TEB. It was found that pure 1,3,5-TEB underwent cracking reaction to produce DEB and EB. The isomerization of 1,3,5-TEB was more active at low temperature while cracking was more active at high temperature. The temperature of 350°C was observed as the optimum for production of maximum amount of DEB. Kinetic parameters for the disappearance of 1,3,5-TEB during its transformation reaction via cracking and isomerization pathways were calculated using the catalyst activity decay function based on time-on-stream (TOS). The apparent activation energies decrease in order E secondary cracking>E primary racking>E isomerization for ZSM-5 catalysts. © 2010 Elsevier B.V.

  3. Transalkylation of ethyl benzene with triethylbenzene over ZSM-5 zeolite catalyst

    Naseem Akhtar, M.; Tukur, N. M.; Al-Yassir, N.; Al-Khattaf, S.; Čejka, Jiří

    2010-01-01

    Roč. 163, 1-2 (2010), s. 98-107. ISSN 1385-8947 Institutional research plan: CEZ:AV0Z40400503 Keywords : ethylbenzene * triethylbenzene * transalkylation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.074, year: 2010

  4. Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

    Zhang, Tian; Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar; Jessica A. Smith; Bain, Timothy S.; Derek R. Lovley

    2013-01-01

    Anaerobic activation of benzene is expected to represent a novel biochemistry of environmental significance. Therefore, benzene metabolism was investigated in Geobacter metallireducens, the only genetically tractable organism known to anaerobically degrade benzene. Trace amounts (

  5. Volatilization of Benzene in a River

    Eric Dunlop

    2013-01-01

    Full Text Available Benzene is a volatile organic compound: when it contaminates a river, some of the substance will evaporate as it flows through. We examine the volumetric flow rate to find how volatilization affects the concentration levels of benzene as the substance flows through several consecutive sections of a river, using a specific example to illustrate the general method.

  6. 46 CFR 30.25-3 - Benzene.

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Benzene. 30.25-3 Section 30.25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Commodities Regulated § 30.25-3 Benzene. The provisions contained in 46 CFR part 197, subpart C, apply to liquid cargoes containing 0.5% or more...

  7. 46 CFR 151.50-60 - Benzene.

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 151.50-60 Section 151.50-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-60 Benzene. The person in charge of...

  8. 29 CFR 1926.1128 - Benzene.

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Benzene. 1926.1128 Section 1926.1128 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1128 Benzene....

  9. 29 CFR 1915.1028 - Benzene.

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Benzene. 1915.1028 Section 1915.1028 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Benzene. Note: The requirements applicable to shipyard employment under this section are identical...

  10. 29 CFR 1910.1028 - Benzene.

    2010-07-01

    ... safety data sheet (MSDS) which addresses benzene and complies with 29 CFR 1910.1200. (ii) Employers who... the requirements of 29 CFR 1910.1200(h) (1) and (2), and shall include specific information on benzene... and unloading operations, except for the provisions of 29 CFR 1910.1200 as incorporated into...

  11. Bio sensing Benzene in the refinery

    A biosensor based on Pseudomonas putida cells was utilized for Benzene analysis in air of an oil refinery. Biosensoristic approach was compared to gaschromatografic essay. We also developed bio sensing Benzene genetically modified Escherichia coli and tested them with refinery samples. Microbial biosensor were useful to determine air pollution.

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

    Pedersen, A.R.; Arvin, E.

    1997-01-01

    4.0 g m(-3). The toluene elimination increased linearly with increasing load, and at maximum load the elimination was 50 g m(-3) h(-1) (70% purification efficiency). This was in accordance with reported values for toluene removal in trickling filters. The removal was determined by the gas...

  13. PERFORMANCE OF TRICKLE BED BIOFILTERS UNDER HIGH TOLUENE LOADING

    The performance of two pelletized media biofilters, highly loaded with toluene, was evaluated in this study. oth biofilters were operated as the same influent concentration of 250 ppmv toluene. iofilter "A" was operated at 1 minute EBRT and biofilter "B" at 0.67 minute EBRT. he i...

  14. CARDIOVASCULAR AND THERMOREGULATORY RESPONSE TO ORAL TOLUENE IN THE RAT.

    Toluene and other volatile organic compounds have often been shown to affect behavior in animals when given by inhalation, and less effective when given orally. Previous work showed that toluene increased heart rate (HR) and motor activity (MA), and reduced core temperature (Tc) ...

  15. 21 CFR 520.580 - Dichlorophene and toluene capsules.

    2010-04-01

    ... CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dichlorophene and toluene capsules. 520.580... Dichlorophene and toluene capsules. (a) Specifications. Each soft gelatin capsule contains 50 milligrams...

  16. Toluene-water clusters: Ion fragmentation and chemistry

    Li, Shijian; Bernstein, Elliot R.

    1992-07-01

    Toluene/water cluster ion fragmentation is studied for isolated cold clusters by means of one- and two-color mass resolved excitation spectroscopy, time resolved pump (S1?S0) probe (I?S1) spectroscopy on the nanosecond time scale, and nozzle/laser delay timing experiments. These experiments lead to an identification of parent clusters for all fragment ion clusters observed. Fragmentation reactions depend on cluster size and on the energy deposited in the ion by the two photon I?S1?S0 excitation sequence. Fragments identified by these techniques include (H2O)xH+ (x=3,...,6) and toluene+(H2O)n-1 for toluene(H2O)n clusters and (H2O)xD+, (H2O)xH+, and toluene-d+3(H2O)n-1 for toluene-d3(H2O)n clusters. For n?3 the preferred cluster fragmentation pathway is loss of a single H2O molecule, while for n?4 the preferred cluster fragmentation pathway is generation of (H2O)nH+. Cluster ion fragmentation is prevalent in this system because of product stability (i.e., solvated protons and the benzyl radical) and because the I?S1 transition leaves the cluster ion in a very highly excited vibrational state (?v?0 for the I?S1 transition). The fragmentation of toluene+(H2O)3 to generate (H2O)3H+ and a benzyl radical takes place by two distinct pathways with generation times ?1<60 ns and ?2=480 ns. The toluene+(H2O)2 fragmentation from toluene+(H2O)3 has a generation time of ?<60 ns. The possible energetics, kinetics, and mechanisms for these fragmentations are discussed.

  17. Molecular dynamics simulation of benzene

    Trumpakaj, Zygmunt; Linde, Bogumił B. J.

    2016-03-01

    Intermolecular potentials and a few models of intermolecular interaction in liquid benzene are tested by Molecular Dynamics (MD) simulations. The repulsive part of the Lennard-Jones 12-6 (LJ 12-6) potential is too hard, which yields incorrect results. The exp-6 potential with a too hard repulsive term is also often used. Therefore, we took an expa-6 potential with a small Gaussian correction plus electrostatic interactions. This allows to modify the curvature of the potential. The MD simulations are carried out in the temperature range 280-352 K under normal pressure and at experimental density. The Rayleigh scattering of depolarized light is used for comparison. The results of MD simulations are comparable with the experimental values.

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

    Døssing, M; Bælum, Jesper; Hansen, S H; Lundqvist, G R

    1984-01-01

    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-cresol or......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...

  19. Airborne concentrations of benzene associated with the historical use of some formulations of liquid wrench.

    Williams, Pamela R D; Knutsen, Jeffrey S; Atkinson, Chris; Madl, Amy K; Paustenbach, Dennis J

    2007-08-01

    The current study characterizes potential inhalation exposures to benzene associated with the historical use of some formulations of Liquid Wrench under specific test conditions. This product is a multiuse penetrant and lubricant commonly used in a variety of consumer and industrial settings. The study entailed the remanufacturing of several product formulations to have similar physical and chemical properties to most nonaerosol Liquid Wrench formulations between 1960 and 1978. The airborne concentrations of benzene and other constituents during the simulated application of these products were measured under a range of conditions. Nearly 200 breathing zone and area bystander air samples were collected during 11 different product use scenarios. Depending on the tests performed, average airborne concentrations of benzene ranged from approximately 0.2-9.9 mg/m(3) (0.08-3.8 ppm) for the 15-min personal samples; 0.1-8 mg/m(3) (0.04-3 ppm) for the 1-hr personal samples; and 0.1-5.1 mg/m(3) (0.04-2 ppm) for the 1-hr area samples. The 1-hr personal samples encompassed two 15-min product applications and two 15-min periods of standing within 5 to 10 feet of the work area. The measured airborne concentrations of benzene varied significantly based on the benzene content of the formulation tested (1%, 3%, 14%, or 30% v/v benzene) and the indoor air exchange rate but did not vary much with the base formulation of the product or the two quantities of Liquid Wrench used. The airborne concentrations of five other volatile chemicals (ethylbenzene, toluene, total xylenes, cyclohexane, and hexane) were also measured, and the results were consistent with the volatility and concentrations of these chemicals in the product tested. A linear regression analysis of air concentration compared with the chemical mole fraction in the solution and air exchange rate provided a relatively good fit to the data. The results of this study should be useful for evaluating potential inhalation exposures to benzene and other volatile chemicals that occurred during the past use of some formulations of Liquid Wrench and perhaps for some similar products containing these chemicals. PMID:17558801

  20. Extraction spectrophotometric method for the determination of trace thorium using 8-hydroxyquinoline and ethyl violet

    A new highly sensitive colour system for thorium is developed. An association complex of thorium ion is formed with 8-hydroxyquinoline and ethyl violet having absorption maximum at 607 nm. The complex can be extracted into 10 ml of a mixture of benzene and MIBK (3:1) in 1 min. Its apparent ε value is 7.5 x 105 l·mol-1·cm-1 at 607 nm. Optimum conditions for the extraction have been found to be 3.5 x 10-3 mol/l sulfuric acid, 0.020 mol/l 8-hydroxyquinoline and 0.018% ethyl violet. Berr's law is obeyed for 0-4.5 μg of thorium per 10 ml. The colour of the extract is stable in 110 minutes at room temperature. The effects of 32 foreign ions and 4 complex reagents on the determination are discussed

  1. Ethyl 1-(butan-2-yl-2-(2-methoxyphenyl-1H-benzimidazole-5-carboxylate

    Natarajan Arumugam

    2011-12-01

    Full Text Available In the title compound, C21H24N2O3, the mean planes of the benzene ring and the benzimidazole ring system form a dihedral angle of 69.94?(7. The ethyl group atoms of the ethanoate fragment are disordered over two sets of sites, with refined occupancies of 0.742?(6 and 0.258?(6. In the crystal, there are weak CH...N hydrogen bonds which connect molecules into chains along the b axis. A weak intermolecular CH...? interaction is also observed.

  2. t-3-Ethyl-r-2,c-6-bis(4-methoxyphenyl-1-nitrosopiperidin-4-one

    T. Kavitha

    2009-08-01

    Full Text Available In the title molecule, C21H24N2O4, the piperidine ring adopts a distorted boat conformation with the ethyl substituent in the axial position. The dihedral angle between the two benzene rings is 70.25 (9°. An intramolecular C—H...O interaction is observed. In the crystal, molecules are linked into a chain along the c axis by C—H...O hydrogen bonds and the chains are linked via weak C—H...π interactions.

  3. Crystal structure of ethyl 2-(2,4,5-trimethoxyphenyl)quinoline-4-carboxylate

    Shrungesh Kumar, T. O.; Naveen, S.; Kumara, M. N.; K. M. Mahadevan; Lokanath, N. K.

    2015-01-01

    In the title compound, C21H21NO5, the dihedral angle between the quinoline ring system (r.m.s. deviation = 0.028?) and the trimethoxybenzene ring is 43.38?(5). The C atoms of the methoxy groups deviate from their attached benzene ring by ?0.396?(2), ?0.049?(2) and 0.192?(2)? for the ortho-, meta- and para-substituents, respectively. The pendant ethyl chain is disordered over two orientations in a 0.527?(5):0.473?(5) ratio. A short intramolecular CH...O contact closes an S(6) ring. In the ...

  4. Selective extraction of toluene from n-heptane using [emim][SCN] and [bmim][SCN] ionic liquids as solvents

    Highlights: • LLE for {n-heptane + toluene + [emim][SCN] or [bmim][SCN]} at 313.2 K were measured. • LLE data were successfully correlated to the NRTL model. • Di and α2,1 were compared to those of sulfolane and other highly selective ILs. • [emim][SCN] and [bmim][SCN] showed higher selectivities than sulfolane. • Physical properties of [emim][SCN] were suitable to be applied at industrial scale. - Abstract: Among the ionic liquids (ILs) studied so far in the liquid–liquid extraction of aromatic hydrocarbons, only a few of them have shown aromatic distribution ratios and aromatic/aliphatic selectivities considerably higher than those of conventional organic solvents, such as sulfolane. Moreover, these ILs had high dynamic viscosities that could limit their application at industrial scale. In this work, we have studied the performance of 1-ethyl-3-methylimidazolium thiocyanate ([emim][SCN]) and 1-butyl-3-methylimidazolium thiocyanate ([bmim][SCN]) ILs in the liquid–liquid extraction of toluene from n-heptane at 313.2 K. Densities, dynamic viscosities, and surface tensions of the ILs were also measured to evaluate their suitability as aromatic extraction solvents. In spite of the high selectivities and toluene distribution ratios of [bmim][SCN], its high dynamic viscosity could imply an important drawback. By contrast, the [emim][SCN] shown toluene/n-heptane selectivities three times higher of the sulfolane values and also substantially higher than those of other promising ILs. Futhermore, densities, viscosities, and surface tensions of [emim][SCN] were also appropriate to consider this IL as an alternative to organic solvents

  5. Interphase cytogenetics of workers exposed to benzene

    Zhang, L.; Wang, Yunxia; Venkatesh, P. [Univ. of California, Berkeley, CA (United States)] [and others

    1996-12-01

    Fluorescence in situ hybridization (FISH) is a powerful new technique that allows numerical chromosome aberrations (aneuploidy) to be detected in interphase cells. In previous studies, FISH has been used to demonstrate that the benzene metabolites hydroquinone and 1,2,4-benzenetriol induce aneuploidy of chromosomes 7 and 9 in cultures of human cells. In the present study, we used an interphase FISH procedure to perform cytogenetic analyses on the blood cells of 43 workers exposed to benzene (median=31 ppm, 8-hr time-weighted average) and 44 matched controls from Shanghai, China. High benzene exposure (>31 ppm, n=22) increased the hyperdiploid frequency of chromosome 9 (p<0.01), but lower exposure (<31 ppm, n=21) did not. Trisomy 9 was the major form of benzene-induced hyperdiploidy. The level of hyperdiploidy in exposed workers correlated with their urinary phenol level (r= 0.58, p < 0.0001), a measure of internal benzene close. A significant correlation was also found between hyperdiploicly and decreased absolute lymphocyte count, an indicator of benzene hematotoxicity, in the exposed group (r=-0.44, p=0.003) but not in controls (r=-0.09, P=0.58). These results show that high benzene exposure induces aneuploidy of chromosome 9 in nondiseased individuals, with trisomy being the most prevalent form. They further highlight the usefulness of interphase cytogenetics and FISH for the rapid and sensitive detection of aneuploidy in exposed human populations. 35 refs., 3 figs., 2 tabs.

  6. Role of charge transfer and spin-orbit coupling in fluorescence quenching. A case study with oxonine and substituted benzenes

    Foell, R.E.; Kramer, H.E.A. (Universitaet Stuttgart (West Germany)); Steiner, U.E. (Universitaet Konstanz (West Germany))

    1990-03-22

    Fluorescence quenching of oxonine in methanol was investigated by means of a computerized dye laser flash spectrometer for the {Delta}G{degree}{sub et} dependence of the quenching rate constant (k{sub q}) and the efficiencies of induced dye triplet formation ({eta}{sub T}), reduced dye radical formation ({eta}{sub R}), and induced internal conversion. A total of 34 substituted benzenes including 20 monohalogenated benzenes, toluenes, and anisoles were used as quenchers spanning a range of {minus}0.85 {le} {Delta}G{degree}{sub et} {le} 1.4 eV for a possible photoelectron-transfer reaction with the dye singlet as electron acceptor. Induced internal conversion was the dominating channel in all cases.

  7. Identification of C[sub 2]-C[sub 4] alkylated benzenes in flash pyrolysates of kerogens, coals and asphaltenes

    Hartgers, W.A.; Sinninghe Damste, J.S.; de Leeuw, J.W. (Delft University of Technology, Delft (Netherlands). Organic Geochemistry Unit)

    1992-08-14

    Pseudo-Kovats indices were determined for all positional isomers of C[sub 2]-C[sub 4] alkylated benzenes using a non-polar capillary column (CP Sil[sub -5]). These indices were applied in combination with mass spectral data to identify these compounds in complex mixtures of a relatively non-polar nature generated upon flash pyrolysis of macromolecular sedimentary organic matter (kerogens, asphaltenes and coals). Alkylbenzene distribution patterns were constructed by integration of appropriate mass chromatograms. Generally, toluene is the major pyrolysis product. Other specific alkylated benzenes (e.g. 1,2,3,4-tetramethylbenzene and 1-methyl-4-isopropylbenzene) were found to be enhanced in flash pyrolysates of different samples. Flash pyrolysates of asphaltene and kerogen fractions isolated from the same oil shale exhibit similar alkylbenzene distributions.

  8. 21 CFR 184.1293 - Ethyl alcohol.

    2010-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl alcohol. 184.1293 Section 184.1293 Food and... Substances Affirmed as GRAS 184.1293 Ethyl alcohol. (a) Ethyl alcohol (ethanol) is the chemical C2H5OH....

  9. Hepatotoxic potential of combined toluene-chronic ethanol exposure

    Howell, S.R.; Christian, J.E.; Isom, G.E.

    1986-05-01

    The hepatoxic properties of concurrent chronic oral ethanol ingestion and acute toluene inhalation were evaluated. Male rats were maintained on ethanol-containing or control liquid diets for 29 days. Animals of each group were subjected to five 20-min exposures to 10 000 ppm toluene with 30 min of room air inhalation between exposures on days 22, 24, 26, and 28 of liquid diet feeding. Some of the ethanol-fed animals were withdrawn from ethanol 14 h before exposure. Ethanol-withdrawn animals displayed an increased sensitivity to the narcotic action of toluene. Animals were sacrificed and assays performed on day 29. Stress markers (plasma corticosterone, free fatty acid, and glucose) were not affected by treatments. A modest elevation in plasma aspartate amino-transferase occurred in non-withdrawn animals receiving both ethanol and toluene. Ethanol-toluene exposure increased both relative liver weight and liver triglycerides. Toluene antagonized the hypertriglyceridemia associated with chronic ethanol ingestion. This study indicates that combined ethanol and toluene exposure has minor potential to induce acute liver injury, but results in altered deposition of hepatic triglycerides.

  10. Enhanced visible-light induced degradation of benzene on Mg-ferrite/hematite/PANI nanospheres: In situ FTIR investigation

    Graphical abstract: The dramatic enhanced visible-light photocatalytic activity of Mg-ferrite/hematite nanospheres photocatalyst on benzene were obtained after hybridized by polyaniline (PANI) using the chemisorption method. The enhancement of photocatalytic degradation of benzene under visible-light irradiation was mainly ascribed to the high efficiency of charge separation induced by the hybrid effect of PANI and Mg-ferrite/hematite. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO2 is produced as the final product during the reaction process. Highlights: ► Mg-ferrite/hematite/PANI photocatalysts showed enhanced photocatalytic activity. ► Ethyl acetate, carboxylic acid and aldehyde were the intermediate products. ► CO2 was produced as the final product during the reaction process. ► The high efficiency of charge separation was mainly ascribed to the hybrid effect. - Abstract: The dramatic enhanced visible-light photocatalytic activity of Mg-ferrite/hematite nanospheres photocatalysts on benzene were obtained after hybridized by polyaniline (PANI) using the chemisorption method. The samples were characterized by scanning electron microscope, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra and UV–Vis diffuse reflectance spectroscopy. The enhancement of photocatalytic degradation of benzene under visible-light irradiation was mainly ascribed to the high efficiency of charge separation induced by the hybrid effect of PANI and Mg-ferrite/hematite. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO2 is determined as the final product during the reaction process.

  11. Enhanced visible-light induced degradation of benzene on Mg-ferrite/hematite/PANI nanospheres: In situ FTIR investigation

    Shen, Yu [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Zhao, Qidong [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Li, Xinyong, E-mail: xyli@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Yuan, Deling; Hou, Yang [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Liu, Shaomin, E-mail: shaomin.liu@curtin.edu.au [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)

    2012-11-30

    Graphical abstract: The dramatic enhanced visible-light photocatalytic activity of Mg-ferrite/hematite nanospheres photocatalyst on benzene were obtained after hybridized by polyaniline (PANI) using the chemisorption method. The enhancement of photocatalytic degradation of benzene under visible-light irradiation was mainly ascribed to the high efficiency of charge separation induced by the hybrid effect of PANI and Mg-ferrite/hematite. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO{sub 2} is produced as the final product during the reaction process. Highlights: Black-Right-Pointing-Pointer Mg-ferrite/hematite/PANI photocatalysts showed enhanced photocatalytic activity. Black-Right-Pointing-Pointer Ethyl acetate, carboxylic acid and aldehyde were the intermediate products. Black-Right-Pointing-Pointer CO{sub 2} was produced as the final product during the reaction process. Black-Right-Pointing-Pointer The high efficiency of charge separation was mainly ascribed to the hybrid effect. - Abstract: The dramatic enhanced visible-light photocatalytic activity of Mg-ferrite/hematite nanospheres photocatalysts on benzene were obtained after hybridized by polyaniline (PANI) using the chemisorption method. The samples were characterized by scanning electron microscope, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra and UV-Vis diffuse reflectance spectroscopy. The enhancement of photocatalytic degradation of benzene under visible-light irradiation was mainly ascribed to the high efficiency of charge separation induced by the hybrid effect of PANI and Mg-ferrite/hematite. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO{sub 2} is determined as the final product during the reaction process.

  12. Benzene and ethylene in Bio-SNG production. Nuisance, fuel or valuable products?

    Rabou, L.P.L.M. Rabou; Van der Drift, A. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2011-11-15

    Gasification of biomass with the aim to produce Substitute Natural Gas (SNG) is best performed at temperatures around 850C, where 50% of the combustion value of the producer gas is concentrated in hydrocarbons. After removal of the heavy hydrocarbons (i.e. tar) and sulphur components, the producer gas can be converted catalytically to a mixture of mainly methane, carbon dioxide and water. Using producer gas as intermediate instead of syngas can lead to 10% higher efficiency, as producer gas does contain a significant amount of methane already and because less heat is evolved in the conversion of the remainder than for a mixture of carbon monoxide and hydrogen. Some of the hydrocarbons in producer gas, notably benzene, toluene, acetylene and ethylene, together with some of the more volatile tar compounds, can be a nuisance in the conversion step, as they easily form carbon deposits on the methanation catalysts involved. Several strategies can be followed to make these annoying components useful. Here, we will focus on benzene and ethylene, as each represents nearly 90% of the total amount of aromatic and unsaturated hydrocarbons respectively in biomass producer gas. One approach, followed in the SNG demonstration plant in Guessing, is to remove benzene nearly completely from producer gas in a low-temperature scrubber. Recovered benzene with some of the scrubbing liquid is used as fuel to provide heat for the gasifier. Any benzene remaining in the producer gas and ethylene are converted in the fluidized bed methanation reactor. The fluidized bed creates conditions in which carbon deposits are gasified before they can harm the catalyst performance. The use of benzene as heat source in the gasifier reduces the need to burn part of the producer gas for that purpose. Effectively, more 'clean' producer gas becomes available for the methanation step. The MILENA type gasifier developed by ECN has a lower heat demand than the Guessing FICFB gasifier. Consequently, it has no use for benzene as an additional heat source. That is why ECN research focuses on solving problems associated with the conversion of benzene and ethylene to methane. One of the problems is removal of organic sulphur compounds, especially thiophene and its derivatives like benzo-thiophene. The main route pursued by ECN is conversion of thiophenes by a hydrodesulphurization (HDS) catalyst, followed by adsorption of the hydrogensulphide produced. Benzene removed from producer gas by liquid scrubbing or adsorption to a solid sorbent can also be recovered for use as fuel in a separate boiler. An advantage of that approach would be that benzene can be stored more easily than producer gas to match heat production with demand by e.g. a district heat system or to provide heat during gasifier maintenance. In fact, that would copy the approach followed in Harbooere with tar. Another promising option is cryogenic separation of producer gas. In principle, that would make it possible to separate and recover not only benzene but also ethylene. Even without purification, these may have more value as chemical base materials than when used as fuel. The cryogenic treatment would probably also capture sulphur compounds, thus considerably simplifying the gas cleaning needed for protection of the methanation catalyst. Advantages and disadvantages of the above options will be discussed. Experimental results of ECN research on hydrodesulphurization and adsorbents will be presented. Further research questions will be addressed.

  13. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    2010-10-01

    ... appendices A and B of this subpart or a MSDS on benzene meeting the requirements of 29 CFR 1910.1200(g) is... 46 Shipping 7 2010-10-01 2010-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  14. Recommended sublimation pressure and enthalpy of benzene

    Highlights: • Sublimation pressures of benzene were measured. • Benzene thermodynamic properties in the state of ideal gas were calculated. • Recommended sublimation pressure and enthalpy of benzene were developed. -- Abstract: Recommended vapor pressures of solid benzene (CAS Registry Number: 71-43-2) which are consistent with thermodynamically related crystalline and ideal-gas heat capacities as well as with properties of the liquid phase at the triple point temperature (vapor pressure, enthalpy of vaporization) were established. The recommended data were developed by a multi-property simultaneous correlation of vapor pressures and related thermal data. Vapor pressures measured in this work using the static method in the temperature range from 233 K to 260 K, covering pressure range from 99 Pa to 1230 Pa, were included in the simultaneous correlation. The enthalpy of sublimation was established with uncertainty significantly lower than the previously recommended values

  15. Rheology of asphaltene-toluene/water interfaces.

    Sztukowski, Danuta M; Yarranton, Harvey W

    2005-12-01

    The stability of water-in-crude oil emulsions is frequently attributed to a rigid asphaltene film at the water/oil interface. The rheological properties of these films and their relationship to emulsion stability are ill defined. In this study, the interfacial tension, elastic modulus, and viscous modulus were measured using a drop shape analyzer for model oils consisting of asphaltenes dissolved in toluene for concentrations varying from 0.002 to 20 kg/m(3). The effects of oscillation frequency, asphaltene concentration, and interface aging time were examined. The films exhibited viscoelastic behavior. The total modulus increased as the interface aged at all asphaltene concentrations. An attempt was made to model the rheology for the full range of asphaltene concentration. The instantaneous elasticity was modeled with a surface equation of state (SEOS), and the elastic and viscous moduli, with the Lucassen-van den Tempel (LVDT) model. It was found that only the early-time data could be modeled using the SEOS-LVDT approach; that is, the instantaneous, elastic, and viscous moduli of interfaces aged for at most 10 minutes. At longer interface aging times, the SEOS-LVDT approach was invalid, likely because of irreversible adsorption of asphaltenes on the interface and the formation of a network structure. PMID:16316096

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

    Sreedevi Upadhyayula

    2009-03-01

    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 to increase with increase in the Si of the catalysts. The effect of temperature on yields of cymene was studied in the range of 453 to 553 K. The highest yield and selectivity for cymene was observed at 513 K. Good cymene selectivity was confirmed with the absence of -propyl toluene in the product. The catalyst activity, in terms of -cymene selectivity, remained almost stable during a nine hour time on stream run. Enhanced cymene selectivity and decreased -cymene selectivity was observed with increase in the toluene to isopropyl alcohol feed mole ratio from 2 to 8. Power law model and L-H-H-W model fitted the experimental data well and are used to explain the kinetics of this reaction.

  17. Antipyrine clearance during experimental and occupational exposure to toluene

    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 into...... four groups. Eighteen printers and 21 controls were exposed to 100 ppm of toluene during 6.5 hours in an exposure chamber. The remaining 18 printers and 18 controls were exposed to 0 ppm of toluene under similar conditions. The salivary clearance of antipyrine was measured immediately after the stay in...... antipyrine 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...

  18. Interactions between Asphaltenes and Water in Solutions in Toluene

    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...

  19. 78 FR 37818 - Request for Information on Toluene Diisocyanates

    2013-06-24

    ... published a Current Intelligence Bulletin on toluene diisocyanate (TDI) and toluenediamine (TDA) [DHHS (NIOSH) Publication No. 90-101] which classified TDI and TDA (used in the manufacturing of TDI)...

  20. Solubility data for toluene in various aqueous alkanolamine solutions

    This paper is the second part concerning the study of the solubility of aromatics in aqueous alkanolamine solutions. Vapor pressures over (liquid + liquid) mixtures and toluene solubility data are reported herein for toluene with pure water and aqueous alkanolamine solutions: monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and diglycolamine[reg] (DGA). Modelling of solubility data are achieved using a simple model based on activity coefficients

  1. Effect of dioxan and toluene as solvents on: Polycondensation leading to poly (2.5-furylene vinylene)s

    This paper describes the influence of two different solvents, on a synthetic route leading to linear poly (2.5-furylene vinylene)s PFV, which involves the polycondensation of 5-methyl furfural in a basic medium, and on the characterization of PFV. The replacement of benzene by dioxan gives a linear polymeric structure possessing a high degree of conjugation, a good degree of polymerization, a remarkable stability to storage under ordinary condition and a partial solubility in common solvents, especially methylene chloride. Casting films from solution polymer gives brittle material, without any mechanical strength. However, the product obtained by using the toluene differs from the expected polymer. The results indicate that the raising of the degree of polymerization was done by increasing the time of reaction and successively introducing the monomer. Monomer, and dimer are isolated and characterized from the sub-product (oligomer) of the reaction. (author)

  2. Radiolysis of Aqueous Benzene Solutions

    Aerated and deaerated aqueous solutions of benzene have been irradiated with 60Co γ-rays. The products of radiolysis in deaerated, unbuffered or acid, solutions were phenol, biphenyl, hydrogen and in acid solutions also hydrogen peroxide with the following yields: G(phenol) = 0. 37 (0. 37), G(biphenyl) = 1.3 (1.7), G(H2) = 0.44 (0. 43) and G(H2O2) = 0 (0.60), the figures in brackets giving the results for acid solutions. The results are shown to agree with the conclusion that k(e-aq + H2O2) >> k(H + H2O2). Furthermore, the results indicate that a competition takes place between the reactions: 2 C6H6OH · -> dimer -> biphenyl. C6H7 · + C6H6OH · -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H2O2) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C6H6)/k(H + O2) was 1.4x10-2. The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe2+ or Fe3+ to aerated acid solutions G(phenol) was increased to 6.6 and 3.4 respectively. Oxygen was consumed more rapidly in the presence of Fe. Reaction mechanisms are discussed

  3. Excess parameter studies on the binary mixtures of toluene with ketones at different temperatures

    Rajagopal, K. [Department of Physics, Government College of Engineering, Tirunelveli 627 007, Tamilnadu (India); Chenthilnath, S., E-mail: chenthilnaths@rediffmail.co [Department of Physics, Satyam College of Engineering and Technology, Satyam Nagar, Aralvaimozhy, Nagercoil 629 301, Tamilnadu (India)

    2010-05-15

    Density, rho, ultrasonic speed, u, and viscosity, eta of binary mixtures of toluene with acetone (AC), ethyl methyl ketone (EMK), and acetophenone (AP), including those of pure liquids are measured over the entire composition range at temperatures (298.15, 303.15, and 308.15) K respectively. From these experimental results, deviations in isentropic compressibility, DELTAk{sub s} and ultrasonic speed, DELTAu, excess intermolecular free length, L{sub f}{sup E}, excess Gibbs free energy of activation, DELTAG*{sup E}, partial molar volumes (V-bar{sub m,1}{sup 0},V-bar{sub m,2}{sup 0},V-bar{sub p}hi{sub ,1}{sup 0},V-bar{sub p}hi{sub ,2}{sup 0}) partial molar compressibilities (K-bar{sub m,1}{sup 0},K-bar{sub m,2}{sup 0},K-bar{sub p}hi{sub ,1}{sup 0}, and K-bar{sub p}hi{sub ,2}{sup 0}) and their excess values (V-bar{sub m,1}{sup 0E},V-bar{sub m,2}{sup 0E},V-bar{sub p}hi{sub ,1}{sup 0E},V-bar{sub p}hi{sub ,2}{sup 0E},K-bar{sub m,1}{sup 0E},K-bar{sub m,2}{sup 0E}, K-bar{sub p}hi{sub ,1}{sup 0E}, and K-bar{sub p}hi{sub ,2}{sup 0E}) of the components at infinite dilution are calculated. The values of DELTAk{sub s} and L{sub f}{sup E} are found to be negative, and those of DELTAu and DELTAG*{sup E} are found to be positive, indicating the presence of specific interactions between toluene and ketone molecules and the interactions follow the order: AC > EMK > AP.

  4. Metabolic by-products of anaerobic toluene degradation by sulfate-reducing enrichment cultures.

    Beller, H. R.; Reinhard, M.; Grbić-Galić, D

    1992-01-01

    Two dead-end metabolites of anaerobic toluene transformation, benzylsuccinic acid and benzylfumaric acid, accumulated in sulfate-reducing enrichment cultures that were fed toluene as the sole carbon source. Stable isotope-labeled toluene and gas chromatography-mass spectrometry were used to confirm that the compounds resulted from toluene metabolism. The two metabolites constituted less than 10% of the toluene carbon (over 80% was mineralized to carbon dioxide, according to a previous study)....

  5. Stable Hydrogen and Carbon Isotope Fractionation during Microbial Toluene Degradation: Mechanistic and Environmental Aspects

    Morasch, Barbara; Richnow, Hans H; Schink, Bernhard; Meckenstock, Rainer U.

    2001-01-01

    Primary features of hydrogen and carbon isotope fractionation during toluene degradation were studied to evaluate if analysis of isotope signatures can be used as a tool to monitor biodegradation in contaminated aquifers. D/H hydrogen isotope fractionation during microbial degradation of toluene was measured by gas chromatography. Per-deuterated toluene-d8 and nonlabeled toluene were supplied in equal amounts as growth substrates, and kinetic isotope fractionation was calculated from the shi...

  6. Measurements of two-photon absorption cross sections for liquid benzene and methyl benzenes

    Two-photon cross sections of neat benzene and methyl substituted benzenes at various wavelengths for selective excitation were measured by two-photon induced fluorescence spectra for the first time. The results show that the two-photon rate increases rapidly with the frequency of the photon

  7. Comparison of Benzene & Toluene removal from synthetic polluted air with use of Nano photocatalyticTiO2/ ZNO process

    Gholami, Mitra; Nassehinia, Hamid Reza; Jonidi-Jafari, Ahmad; Nasseri, Simin; Esrafili, Ali

    2014-01-01

    Background Mono aromatic hydrocarbons (BTEX) are a group of hazardous pollutants which originate from sources such as refineries, gas, and oil extraction fields, petrochemicals and paint and glue industries. Conventional methods, including incineration, condensation, adsorption and absorption have been used for removal of VOCs. None of these methods is economical for removal of pollutants of polluted air with low to moderate concentrations. The heterogeneous photocatalytic processes involve t...

  8. Health Risk Assessment of Ambient Air Concentrations of Benzene, Toluene and Xylene (BTX) in Service Station Environments

    Benjamin Edokpolo; Qiming Jimmy Yu; Des Connell

    2014-01-01

    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 obtain...

  9. Survey of extreme solvent tolerance in gram-positive cocci: membrane fatty acid changes in Staphylococcus haemolyticus grown in toluene.

    Nielsen, Lindsey E; Kadavy, Dana R; Rajagopal, Soumitra; Drijber, Rhae; Nickerson, Kenneth W

    2005-09-01

    We exploited the unique ecological niche of oil fly larval guts to isolate a strain of Staphylococcus haemolyticus which may be the most solvent-tolerant gram-positive bacterium yet described. This organism is able to tolerate 100% toluene, benzene, and p-xylene on plate overlays and saturating levels of these solvents in monophasic liquid cultures. A comparison of membrane fatty acids by gas chromatography after growth in liquid media with and without toluene showed that in cells continuously exposed to solvent the proportion of anteiso fatty acids increased from 25.8 to 33.7% while the proportion of 20:0 straight-chain fatty acids decreased from 19.3 to 10.1%. No changes in the membrane phospholipid composition were noted. Thus, S. haemolyticus alters its membrane fluidity via fatty acid composition to become more fluid when it is exposed to solvent. This response is opposite that commonly found in gram-negative bacteria, which change their fatty acids so that the cytoplasmic membrane is less fluid. Extreme solvent tolerance in S. haemolyticus is not accompanied by abnormal resistance to anionic or cationic detergents. Finally, six strains of Staphylococcus aureus and five strains of Staphylococcus epidermidis, which were not obtained by solvent selection, also exhibited exceptional solvent tolerance. PMID:16151101

  10. Benzene monitoring at CPPI service stations

    A study was conducted in which ambient airborne concentration levels of benzene were measured at a representative set of gasoline service stations in Toronto and Vancouver. Benzene is considered to be toxic under the Canadian Environmental Protection Act (CEPA). It is a component in gasoline (0.1 to 4.7 per cent by volume) and is present in vehicle evaporative and exhaust emissions. Measurements were made every 18 days at each station for one year. The objective of the study was to assess the ambient and employee exposure levels of benzene at service stations and to determine whether the levels were typical of those published in the literature. In a 1986 PACE (Petroleum Association for Conservation of the Canadian Environment) survey of exposure to gasoline hydrocarbon vapours at Canadian service stations, airborne benzene concentration data was inconsistent with similar ambient and personal exposure data in the international literature. It was concluded that both the mean ambient benzene concentration and the personal exposure level measurements in this study were generally lower than similar measurements made in other countries. The same observation was made with respect to ambient and personal exposure levels measured in this study vis-a-vis those measured during the PACE study conducted in 1985/86. . 31 refs., 24 tabs., 5 figs

  11. Synthesis and characterization of toluene-3,4-dithiolatoantimony(III) derivatives with some oxygen and/or sulphur donor ligands.

    Chauhan, H P S; Bhatiya, Sumit; Bakshi, Abhilasha

    2009-09-15

    Replacement reactions of toluene-3,4-dithiolatoantimony(III) chloride with oxygen and/or sulphur donor ligands like benzoic acid, thiobenzoic acid, thioacetic acid, phenol, thiophenol, sodium salicylate and thio glycolic acid in 1:1 molar ratio as well as disodium oxalate in 2:1 molar ratio in refluxing anhydrous benzene yielded toluene-3,4-dithiolatoantimony(III) mono oxo and/or thio carboxylic or phenolic derivatives of the general formula {R=OOCC(6)H(5), SOCC(6)H(5), SOCCH(3), OC(6)H(5), SC(6)H(5), OOCC(6)H(4)(OH) and SCH(2)COOH} and These newly synthesized derivatives are yellow and brown solids/liquids and are soluble in common organic solvents like benzene, chloroform, dichloromethane, etc. These derivatives have been characterized by melting point determination, molecular weight determination, elemental analysis (C, H, S and Sb), spectral {UV, IR and NMR ((1)H and (13)C)} and thermal (TGA, DTA and DSC) studies. PMID:19560395

  12. Crystal structure of ethyl 2-(diethoxyphosphoryl-2-(2,3,4-trimethoxyphenylacetate

    Moritz Schubert

    2014-09-01

    Full Text Available The title compound, C17H27O8P, was prepared by MichaelisArbuzov reaction of ethyl 2-bromo-2-(2,3,4-trimethoxyphenylacetate and triethyl phosphite. Such compounds rarely crystallize, but single crystals were recovered after the initial oil was left for approximately 10 years. The bond angle of the sp3-hybridized C atom connecting the benzene derivative with the phospho unit is widened marginally [112.5?(2]. The terminal PO bond length of 1.464?(2? clearly indicates a double bond, whereas the two O atoms of the ethoxy groups connected to the phosphorous atom have bond lengths of 1.580?(2? and 1.581?(3?. The three methoxy groups emerge out of the benzene-ring plane due to steric hindrance [CCOC torsion angles = ?179.9?(3, ?52.9?(4 and 115.3?(4]. In the crystal, inversion dimers linked by pairs of CH...O=P hydrogen bonds generate R22(14 loops. The chosen crystal was modelled as a non-merohedral twin.

  13. Separation of the isomers of benzene poly(carboxylic acid)s by quaternary ammonium salt via formation of deep eutectic solvents.

    Hou, Yucui; Li, Jian; Ren, Shuhang; Niu, Muge; Wu, Weize

    2014-11-26

    Because of similar properties and very low volatility, isomers of benzene poly(carboxylic acid)s (BPCAs) are very difficult to separate. In this work, we found that isomers of BPCAs could be separated efficiently by quaternary ammonium salts (QASs) via formation of deep eutectic solvents (DESs). Three kinds of QASs were used to separate the isomers of BPCAs, including the isomers of benzene tricarboxylic acids (trimellitic acid, trimesic acid, and hemimellitic acid) and the isomers of benzene dicarboxylic acids (phthalic acid and isophthalic acid). Among the QASs, tetraethylammonium chloride was found to have the best performance, which could completely separate BPCA isomers in methyl ethyl ketone solutions. It was found that the hydrogen bond forming between QAS and BPCA results in the selective separation of BPCA isomers. QAS in DES was regenerated effectively by the antisolvent method, and the regenerated QAS was reused four times with the same high efficiency. PMID:25351281

  14. Biofiltration of air contaminated with methanol and toluene

    Pakamas Chetpattananondh

    2005-12-01

    Full Text Available Biofiltration of air contaminated with VOCs is inexpensive compared with the conventional techniques and very effective for treating large volumes of moist air streams with low concentrations of VOCs. In this study, biofiltration for the purification of polluted air from methanol, a hydrophilic VOC, and toluene, a hydrophobic VOC, was investigated. The experiments were operated using three separated stainless steel biofilters, for methanol, toluene, and a mixture of methanol and toluene, respectively. Biofilter consisted of a mixture of palm shells and activated sludge as a filter-bed material. Only the indigenous microorganisms of the bed medium without any addition of extra inoculum were used throughout the whole process. The polluted air inlet concentration was varied from 0.3-4.7 g/m3 with flow rates ranging from 0.06-0.45 m3/h, equivalent to the empty bed residence times of 9-71 sec. Polluted air was successfully treated by biofiltration, 100% removal efficiencies would be obtained when the air flow rate was lower than 0.45 m3/h. The presence of toluene did not affect the removal rate of methanol while the removal rate of toluene was decreased with the presence of methanol in air stream according to the competition phenomenon.

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

    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.

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

    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.

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

    Nuria, Vidal; Cristina, Volzone.

    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 bentoni [...] tes. 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. Liquid Phase Behaviour in the Binary System 1-Ethyl-3-Methylimidazolium Ethylsulfate + Alkane (n-Heptane, Methylcyclohexane, Toluene).

    Bendová, Magdalena; Wagner, Zdeněk

    - : Norhaven Book, 2007 - (Gani, R.; Dam-Johansen, K.), s. 25-26 ISBN 978-87-91435-56-0. [European Congress of Chemical Engineering ECCE-6. Copenhagen (DK), 16.09.2007-20.09.2007] R&D Projects: GA ČR(CZ) GP104/06/P066 Institutional research plan: CEZ:AV0Z40720504 Keywords : liquid-liquid equilibrium * ionic liquids * thermodynamic model Subject RIV: CF - Physical ; Theoretical Chemistry

  19. The cyanogen-ethyl ethers of glycerin

    The cyanogen-ethylation is one of the characteristic reaction of hydroxyl comprising compounds and run with addition them to acryl nitride. The catalysis of process are substances, which have basic character

  20. Gas phase nitrosation of substituted benzenes

    Dechamps, Noémie; Gerbaux, Pascal; Flammang, Robert; Bouchoux, Guy; Nam, Pham-Cam; Nguyen, Minh-Tho

    2004-03-01

    Using a combination of tandem mass spectrometric experiments (ion-molecule reactions, collisional activation, neutralization-reionization, MS/MS/MS) and theoretical calculations, protonated substituted benzenes are demonstrated to readily react with neutral t-butyl nitrite by the formation of stable complexes linking ionized nitric oxide to the benzene derivatives. The overall process is proposed to involve the concomitant elimination of neutral 2-methyl-2-propanol. Proton-bound dimers are proposed to intervene as the key-intermediates in these reactions, which also competitively produce protonated t-butyl nitrite. All the experiments were performed in a single hybrid tandem mass spectrometer of sector-quadrupole-sector configuration.

  1. Benzene destruction in claus process by sulfur dioxide: A reaction kinetics study

    Sinha, Sourab

    2014-07-02

    Benzene, toluene and xylene (BTX) are present as contaminants in the H 2S gas stream entering a Claus furnace. The exhaust gases from the furnace enter catalytic units, where BTX form soot particles. These particles clog and deactivate the catalysts. A solution to this problem is BTX oxidation before the gases enter catalyst beds. This work presents a theoretical investigation on benzene oxidation by SO2. Density functional theory is used to develop a detailed mechanism for phenyl radical -SO2 interactions. The mechanism begins with SO2 addition to phenyl radical after overcoming an energy barrier of 6.4 kJ/mol. This addition reaction is highly exothermic, where a reaction energy of 182 kJ/mol is released. The most favorable pathway involves O-S bond breakage, leading to the release of SO. A remarkable similarity between the pathways for phenyl radical oxidation by O2 and its oxidation by SO2 is observed. The reaction rate constants are also evaluated to facilitate process simulations. © 2014 American Chemical Society.

  2. A field campaign for measurement of benzene in urban area of Venice

    A field campaign for the measurement of benzene and toluene in urban areas has been planned by the city of Venice in collaboration with CNR during the period June-July 1994. The measurements were provided by three automatic systems, available from the companies Chrompack, Elecos and Perkin-Elmer. The main aims of this campaign were to collect information on spatial and temporal distribution of these pollutants, in order to estimate the exposure risk for people in an urban polluted environment, and to identify the most reliable and accurate systems to measure this pollutant. From the comparison between the temporal trend of benzene and natural radioactivity it can be deduced that the concentration levels of primary pollutants at ground state are not simply linked to emissions, but they are strongly modulated by atmospheric diffusion processes. The reliability of the experimental results was demonstrated by a statistical treatment, and it was shown that it is necessary to carry out measurements at sufficiently high frequencies to represent the real environmental situation

  3. Sizes of vanadyl petroporphyrins and asphaltene aggregates in toluene

    Dechaine, Greg Paul; Gray, Murray R. [Department of Chemical and Materials Engineering, University of Alberta (Canada)], email: gpd@ualberta.ca

    2010-07-01

    This work focuses on the importance of removing vanadyl porphyrins components from crude oils and the methodology for doing it. The diffusion of asphaltene and vanadium components in diluted toluene was measured using a stirred diaphragm diffusion cell, which was equipped with a number of different cellulosic membranes of different pore size. In-situ UV/visible spectroscopy was used to observe filtrates of the process. The effective diffusivity of asphaltene structures was plotted for different pore sized membranes. It was noticed that asphaltene concentrations increased with increased pore sizes; particularly increasing at pore diameter of 5 nm. Moreover the effects of temperature and mass concentration were also investigated in this study. It was shown that increasing the temperature of the toluene causes the mobility of asphaltene to increase as well. Nevertheless, decreasing the concentration of asphaltene does not affect its mobility. It was shown that toluene samples from different sources showed different mobility.

  4. Survey of benzene and aromatics in Canadian Gasoline - 1994

    A comprehensive database of the benzene and aromatics levels of gasoline produced in or imported into Canada during 1994, was presented. Environment Canada conducted a survey that requested refineries and importers to report quarterly on benzene and aromatics levels in gasoline. Benzene, which has been declared toxic by the Canadian Environmental Protection Act, is found in gasoline and is formed during the combustion of the aromatic components of gasoline. It was shown that benzene and aromatics levels differ regionally and seasonally. There are also variations in benzene levels between batches of gasoline produced at any one refinery. This report listed the responses to the benzene/aromatics survey. It also described the analytical procedures used to measure benzene and aromatics levels in gasoline, and provided guidelines for reporting gasoline benzene and total aromatics data. 7 tabs., 21 figs

  5. Quantitative study of the acidity of HCl in a molten chloroaluminate system (AlCl sub 3 /1-ethyl-3-methyl-1H-imidazolium chloride) as a function of HCl pressure and melt composition (51. 0-66. 4 mol % AlCl sub 3 )

    Smith, G.P.; Dworkin, A.S.; Zingg, S.P. (Oak Ridge National Lab., TN (USA)); Pagni, R.M. (Univ. of Tennessee, Knoxville (USA))

    1989-07-05

    The acidity of HCl in Lewis acid mixtures of AlCl{sub 3} and 1-ethyl-3-methyl-1H-imidazolium chloride (EMIC) has been determined as a function of HCl pressure (P{sub HCl}) and melt composition at ambient temperatures. The equilibrium constant (K{prime}{sub b}) for the protonation of arene bases (B) according to the reaction HCl + B {r reversible} BH{sup +} + Cl{sup {minus}} was determined from the relation log K{prime}{sub B} = H{prime} + log ((BH{sup +})/(B)) with the protonation ratio measured spectrophotometrically and the acidity function, H{prime} = log ((Cl{sup {minus}})/P{sub HCl}), evaluated by using the thermodynamic model of Dymek et al. to calculate (Cl{sup {minus}}). Values of log K{prime}{sub B} were determined for chrysene, fluorene, 2-methylnaphthalene, and mesitylene over a range of HCl pressures and melt compositions, while estimates for benzene, toluene and naphthalene were obtained at a single pressure and composition (1 atm, 66.4 mol % AlCl{sub 3}). The correlation between log K{prime}{sub B} for these arenes in HCl/AlCl{sub 3}-EMIC and log K{sub B} for the same arenes in HF/BF{sub 3} suggests that H{prime} {minus} H{sub 0} {approx equal} 0.4, where H{sub 0} is the Hammett acidity function. According to this criterion H{sub 0} for 0.01 atm HCl in 51 mol % AlCl{sub 3} has a value of {minus}12.6 (a superacid comparable to 100% H{sub 2}SO{sub 4}). At 1 atm HCl, a melt saturated with AlCl{sub 3} at ambient temperatures ({approximately} 67 mol % AlCl{sub 3}) is a much stronger superacid with a value of H{sub 0} on the order of {minus}18.

  6. Laser induced reaction of C60 with toluene

    A series of fullerene derivatives would be produced by the laser induced reaction of C60 with toluene. High performance liquid chromatography combined with mass spectrometry and ultraviolet spectrometry (HPLC-MS-UV) was developed for separation and characterization of the reaction products, comprising C60(C7H7)n, C60Hn and C60(C7H7)nOm. The derivation might be related to the radical intermediates from laser reaction of toluene. Tandem mass spectra (MS/MS) revealed that the intermediates were bonded at the rim of C60 to form derivatives

  7. Synergistic effect of catalyst for oxidation removal of toluene

    A series of experiments was performed for toluene removal from a gaseous influent at the normal temperature and atmospheric pressure by decomposition due to dielectric barrier discharge generated non-thermal plasma, by using MnO2/γ-Al2O3 as catalyst. The removal efficiency of toluene was significantly increased by combining MnO2/γ-Al2O3 with NTP. At the same time, the goal of improving energy efficiency and decreasing O3 from exhaust gas treatment was accomplished.

  8. Developmental neurotoxicity after toluene inhalation exposure in rats

    Hass, Ulla; Lund, Søren Peter; Hougaard, Karin Sørig; Simonsen, Leif

    1999-01-01

    Rats were exposed to 1200 ppm or 0 ppm toluene (CAS 108-88-3) for 6 h per day from day 7 of pregnancy until day 18 postnatally. Developmental and neurobehavioral effects in the offspring were investigated using a test battery including assessment of functions similar to those in the proposed OECD...... was not related to poorer swimming capabilities, because swim speeds were similar to control values. The results show that exposure to 1200 ppm toluene during brain development caused long-lasting developmental neurotoxicity in rats. (C) 1999 Elsevier Science Inc. All rights reserved....

  9. Crystal structure of ethyl 2-(2,4,5-trimethoxyphenyl)quinoline-4-carboxylate

    Shrungesh Kumar, T. O.; Naveen, S.; Kumara, M. N.; K. M. Mahadevan; Lokanath, N. K.

    2015-01-01

    In the title compound, C21H21NO5, the dihedral angle between the quinoline ring system (r.m.s. deviation = 0.028?) and the trimethoxybenzene ring is 43.38?(5). The C atoms of the methoxy groups deviate from their attached benzene ring by ?0.396?(2), ?0.049?(2) and 0.192?(2)? for the ortho-, meta- and para-substituents, respectively. The pendant ethyl chain is disordered over two orientations in a 0.527?(5):0.473?(5) ratio. A short intramolecular CH?O contact closes an S(6) ring. In t...

  10. Benzene derivatives produced by Fusarium graminearum - Short communication.

    Ntushelo, Khayalethu; Setshedi, Itumeleng

    2015-06-01

    Using NMR spectroscopy benzene derivatives were detected in mycelia of Fusarium graminearum, a pathogen of wheat and maize. In previous studies F. graminearum was found to cause cancer to humans and benzene derivatives were detected in breath of cancer sufferers. Surprisingly, no study found benzene derivatives to be the cancerous agents in F. graminearum. In this study we detected benzene derivatives in F. graminearum and propose to study their role as cancer agents. PMID:26081280

  11. Recommended sublimation pressure and enthalpy of benzene

    Růžička, K.; Fulem, Michal; Červinka, C.

    2014-01-01

    Roč. 68, Jan (2014), s. 40-47. ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal-gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

  12. 46 CFR 153.1060 - Benzene.

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 153.1060 Section 153.1060 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Special Cargo Procedures § 153.1060...

  13. Formation of Benzene in the Interstellar Medium

    Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.; Crim, F. Fleming (Editor)

    2010-01-01

    Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block-the aromatic benzene molecule-has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3- butadiene, C2H + H2CCHCHCH2 --> C6H6, + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadlene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium.

  14. Systems biology of human benzene exposure

    2009-01-01

    Toxicogenomic studies, including genome-wide analyses of susceptibility genes (genomics), gene expression (transcriptomics), protein expression (proteomics), and epigenetic modifications (epigenomics), of human populations exposed to benzene are crucial to understanding gene-environment interactions, providing the ability to develop biomarkers of exposure, early effect and susceptibility. Comprehensive analysis of these toxicogenomic and epigenomic profiles by bioinformatics in the context of...

  15. Radiation-induced chlorination of benzene

    Radiation-induced process of the benzene chlorination to achieving the maximum yield of γ-hexachlorocyclohexane (γ-HCH) was investigated. The influence of temperature, flow rate of chlorine and dose rate of γ-radiation was appointed. The addition of such halogenohydrocarbons as dichloromethane and tetrachloroethane, to reacting system increased γ-HCH content in the products mixture. (author)

  16. Extraction of toluene from aliphatic compounds using an ionic liquid as solvent: Influence of the alkane on the (liquid + liquid) equilibrium

    Gonzalez, Emilio J. [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain); Calvar, Noelia, E-mail: noecs@uvigo.e [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Facultade de Engenharia, Universidade de Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Dominguez, Irene; Dominguez, Angeles [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain)

    2011-04-15

    Research highlights: An ionic liquid was analyzed as solvent for extraction of toluene from alkanes. Liquid-liquid equilibrium data were measured at 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio were obtained and compared with literature. The Othmer-Tobias equation was used to ascertain the experimental LLE data. Experimental data were correlated using NRTL and UNIQUAC models. - Abstract: In this paper, the feasibility of using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid, [EMim][ESO{sub 4}], as solvent for the extraction of toluene from aliphatic compounds (hexane, heptane, octane, or nonane) was analyzed. (Liquid + liquid) equilibrium (LLE) data for the ternary systems {l_brace}alkane (1) + toluene (2) + [EMim][ESO{sub 4}] (3){r_brace} were measured at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio were calculated from the experimental LLE data, and the obtained values were compared to those previously reported using other ionic liquids and sulfolane. The degree of consistency of the experimental LLE data was ascertained using the Othmer-Tobias equation. Finally, the experimental LLE data were satisfactorily correlated with NRTL and UNIQUAC models.

  17. Extraction of toluene from aliphatic compounds using an ionic liquid as solvent: Influence of the alkane on the (liquid + liquid) equilibrium

    Research highlights: ? An ionic liquid was analyzed as solvent for extraction of toluene from alkanes. ? Liquid-liquid equilibrium data were measured at 298.15 K and atmospheric pressure. ? Selectivity and solute distribution ratio were obtained and compared with literature. ? The Othmer-Tobias equation was used to ascertain the experimental LLE data. ? Experimental data were correlated using NRTL and UNIQUAC models. - Abstract: In this paper, the feasibility of using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid, [EMim][ESO4], as solvent for the extraction of toluene from aliphatic compounds (hexane, heptane, octane, or nonane) was analyzed. (Liquid + liquid) equilibrium (LLE) data for the ternary systems {alkane (1) + toluene (2) + [EMim][ESO4] (3)} were measured at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio were calculated from the experimental LLE data, and the obtained values were compared to those previously reported using other ionic liquids and sulfolane. The degree of consistency of the experimental LLE data was ascertained using the Othmer-Tobias equation. Finally, the experimental LLE data were satisfactorily correlated with NRTL and UNIQUAC models.

  18. SYNCHROTRON X-RAY MICROTOMOGRAPHY, ELECTRON PROBE MICROANALYSIS, AND NMR OF TOLUENE WASTE IN CEMENT

    Synchrotron X-ray microtomography shows vesicular structures for toluene/cement mixtures, prepared with 1.22 to 3.58 wt% toluene. Three-dimensional imaging of the cured samples shows spherical vesicles, with diameters ranging from 20 to 250 microm; a search with EPMA for vesicles in the range of 1-20 microm proved negative. However, the total vesicle volume, as computed from the microtomography images, accounts for less than 10% of initial toluene. Since the cements were cured in sealed bottles, the larger portion of toluene must be dispersed within the cement matrix. Evidence for toluene in the cement matrix comes from 29Si MAS NMR spectroscopy, which shows a reduction in chain silicates with added toluene. Also, 2H NMR of d8-toluene/cement samples shows high mobility for all, toluene and thus no toluene/cement binding. A model that accounts for all observations follows: For loadings below about 3 wt%, most toluene is dispersed in the cement matrix, with a small fraction of the initial toluene phase separating from the cement paste and forming vesicular structures that are preserved in the cured cement. Furthermore, at loadings above 3 wt%, the abundance of vesicles formed during toluene/cement paste mixing leads to macroscopic phase separation (most toluene floats to the surface of the cement paste)

  19. Contrastive Analysis of the Raman Spectra of Polychlorinated Benzene: Hexachlorobenzene and Benzene

    Zhengjun Zhang

    2011-12-01

    Full Text Available Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In this work we simulate the Raman spectra of hexachlorobenzene and benzene, and figure out the vibration mode of each main peak. The effect on the Raman spectrum of changing substituents from H to Cl is analyzed to reveal the relations between the Raman spectra of homologues and isomers of polychlorinated benzene, which should be helpful for distinguishing one kind of polychlorinated benzene from its homologues and isomers by surface enhanced Raman scattering.

  20. 40 CFR 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (1-methylethyl)(2-phenylethyl... Substances § 721.1350 Benzene, (1-methylethyl)(2-phenylethyl)-. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as benzene,...

  1. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (2-chloroethoxy)-. 721.1210... Substances § 721.1210 Benzene, (2-chloroethoxy)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, (2-chloroethoxy)- (PMN P-87-1471) is subject...

  2. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Bis(imidoethylene) benzene. 721.1187... Substances § 721.1187 Bis(imidoethylene) benzene. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance bis(imidoethylene)benzene (PMN P-93-1447) is subject to...

  3. BENZENE VAPOR DEPLETION IN THE PRESENCE OF PLANTS

    Three plant species, Eichhornia crassipes in a nutrient hydroponic culture Beta vulgaris saccharifera, and Beta vulgaris cicla in soil and in water cultures, were found to deplete benzene from the air. Following benzene depletion, plant tissues were extracted and no benzene was d...

  4. Adsorption of ethyl cellulose on asphaltene- or bitumen-coated hydrophilic silica surfaces

    Wang, Shengqun; Segin, Nataliya; Wang, Ke; Masliyah, Jacob H.; Xu, Zhenghe [Department of Chemical and Materials Engineering, University of Alberta (Canada)], email: zhenghe.xu@ualberta.ca

    2010-07-01

    Previous studies show that ethyl cellulose (EC) is a biodegradable, greener demulsifier for water-oil emulsions that significantly reduces diluted bitumen-water interfacial tension. In this study, the molecular mechanism of EC demulsifiers is investigated using an atomic force microscope (AFM) and a quartz crystal microbalance (QCM). Asphaltenes and bitumen were adsorbed from toluene on a hydrophilic silica wafer, which was soaked in an EC-in-toluene solution for varying periods of time. The EC gradually displaced the asphaltene/bitumen aggregates, pushing them into larger aggregates. The process reached equilibrium in about 7 hours, with EC covering most of the silica surface with large, sporadically scattered aggregates. The EC-dominated surface became more hydrophilic than asphaltene/bitumen-adsorbed surfaces. The QCM study showed that the displacement of pre-adsorbed asphaltenes by EC is irreversible. The affinity of EC to hydrophilic silica surface is stronger than that of asphaltenes, providing further insights into demulsification mechanisms of EC for breaking w/o emulsions. EC also has potential in altering a solid from oil-wet to water-wet.

  5. 1-Ethyl-1H-2,1-benzothiazin-4(3H-one 2,2-dioxide

    Waseeq Ahmad Siddiqui

    2008-03-01

    Full Text Available In the title compound, C10H11NO3S, there is distorted tetrahedral geometry around the S atom. The heterocyclic thiazine ring adopts a half-chair conformation. The ethyl and sulfonyl groups form dihedral angles of 82.53?(13 and 88.91?(9, respectively, with the plane formed by the benzothiazine ring, excluding the S atom; the S atom and the ethyl group lie on opposite sides of the ring. The molecules are linked into dimers by intermolecular CH...O hydrogen bonds involving benzene CH and carbonyl O atoms, thus forming eight-membered rings. The dimers are linked into chains via interactions of a similar type. There is an intramolecular CH...O hydrogen bond.

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

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

    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....

  7. ECO FRIENDLY ROUTE OF DEHYDROGENATION OF 2,3-DIHYDRO-2-PHENYL-4-QUINOLONE TO 2-PHENYL-4-QUINOLONE USING DIACETOXY IODO BENZENE

    PANDE G.B.

    2013-04-01

    Full Text Available As an alternative reagent to various traditional dehydrogenating reagentsDiacetoxy iodo benzene is stable, non-hazardous, acidic and has been successfully usedfor dehydrogenation reactions1.Herein we report a new and ecofriendly route for dehydrogenation of 2,3-dihydro-2-phenyl-4-quinolone to 2-phenyl-4-quinolone using diacetoxy iodo benzene andpotassium hydroxide2.A series of 2,3-dihydro-2-phenyl-4-quinolones3 has been synthesized usingacid-catalyzed one-pot reaction quinolones were prepared through cyclization of thecondensation product that were formed by heating of arylamines and ethylbenzoylacetate in toluene. Similarly, the 6 (7 or 8-substituted 2,3-dihydro-2-phenylquinolones were prepared from the para (ortho or meta-substituted aniline.

  8. HYPERTENSIVE AND TACHYCARDIC RESPONSES TO ORAL TOLUENE IN THE RAT.

    Little is known regarding the effects of toluene and other volatile organic compounds on autonomic processes. Such studies should be performed in unrestrained and undisturbed animals to avoid the effects of handling stress on processes regulated by the autonomic nervous system. T...

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

    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...

  10. Photocatalytic Oxidation Processes for Toluene Oxidation over TiO2 Catalysts

    Yasutake Teraoka; Keisuke Mochiduki; Hisahiro Einaga

    2013-01-01

    Gas-solid heterogeneous photooxidation of toluene over TiO2 catalyst was studied to investigate the factors controlling the catalytic activities. The toluene photooxidation behavior on TiO2 was strongly affected by the formation and oxidation behavior of intermediate compounds on TiO2, and their accumulation decreased the reaction rate for toluene photooxidation. The formation and oxidation behavior of the byproduct compounds depended on the initial concentration of toluene and water vapor. I...

  11. Common induction and regulation of biphenyl, xylene/toluene, and salicylate catabolism in Pseudomonas paucimobilis.

    Furukawa, K.; Simon, J R; Chakrabarty, A M

    1983-01-01

    A strain of Pseudomonas paucimobilis (strain Q1) capable of utilizing biphenyl was isolated from soil. This strain grew not only on substituted biphenyls, but also on salicylate, xylene or toluene or both (xylene/toluene), and substituted benzoates. Evidence is presented that the catabolism of biphenyl, xylene/toluene, and salicylate is regulated by a common unit in this strain. The catabolism of biphenyl, xylene/toluene, and salicylate is interrelated, since benzoate and toluate are common m...

  12. The solvent extraction of vanadium(IV) with HDEHP in benzene and kerosene

    The distribution of vanadium(IV) between sulphuric acid solutions and solutions of bis-(2-ethyl hexyl)phosphoric acid (abbreviated as HDEHP or H2A2) in benzene and kerosene has been investigated as a function of the extractable metal ion, sulphate, acetate, nitrate and extractant concentrations, temperature and the nature of the diluents. The distribution coefficient has been found to increase with increasing concentration of the extractant, acetate, nitrate and temperature and with decreasing acidity and sulphate concentration. From the temperature dependence data, the apparent enthalpy change for the extraction reaction has been calculated to be ΔH = 4.74 kcal/mole. The molecular weight and the phosphorus-vanadium atom ratio of the solid complex have been found to be 2000 and 2:1 respectively. The mechanism of the extraction is discussed. (author)

  13. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Toluene sulfonamide bis-phe-nol A... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  14. Differences in xenobiotic detoxifying activities between bone marrow stromal cells from mice and rats: Implications for benzene-induced hematotoxicity

    Zhu, Hong; Li, Yunbo; Trush, M.A. [Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, MD (United States)

    1995-10-01

    benzene is a human carcinogen; exposure can result in aplastic anemia and leukemia. Data from animal models are frequently used in benzene risk assessment. In rodent studies, mice are more sensitive to benzene-induced hematotoxicity than rats. Bone marrow stromal cells from mice were significantly more susceptible to the cytotoxicity induced by the benzene metabolites hydroquinone (HQ) and benzoquinone (BQ) than cells from rats. Since cellular gluthathione (GSH) and quinone reductase (QR) are known to play critical roles in modulating HQ-induced cytotoxicity, the GSH content and the QR and glutathione S-transferase (GST) activity in stromal cells from both species was measured. In rat cells, the GSH content and the QR specific activity were 2 and 28 times as much as those from mice, respectively. GSH and QR in both mouse and rat stromal cells were inducible by 1,2-dithiole-3-thione (D3T). D3T pretreatment of both mouse and rat stromal cells resulted in a marked protection against HQ-induced toxicity. Pretreatment of both mouse and rat stromal cells with GSH ethyl ester also provided a dramatic protection against HQ-induced toxicity. Conversely, dicoumarol, an inhibitor of QR, enhanced the HQ-induced toxicity in stromal cells from both mice and rats, indicating an important role for QR in modulating HQ-induced stromal toxicity. Buthionine sulfoximine (BSO), which depleted GSH significantly in both species, potentiated the HQ-induced toxicity in mouse but not in rat stromal cells. Surprisingly, incubation of stromal cells with BSO resulted in a significant induction of QR, especially in rats. Overall, this study demonstrates that the differences in stromal cellular GSH content and QR activity between mice and rats contribute to their respective susceptibility to HQ-induced cytotoxicity in vitro, and may be involved in the greater in vivo sensitivity of mice to benzene-induced hematotoxicity. 51 refs., 9 figs., 1 tab.

  15. Proteogenomic elucidation of the initial steps in the benzene degradation pathway of a novel halophile, Arhodomonas sp. strain Rozel, isolated from a hypersaline environment.

    Dalvi, Sonal; Azetsu, Sei; Patrauchan, Marianna A; Aktas, Deniz F; Fathepure, Babu Z

    2012-10-01

    Lately, there has been a special interest in understanding the role of halophilic and halotolerant organisms for their ability to degrade hydrocarbons. The focus of this study was to investigate the genes and enzymes involved in the initial steps of the benzene degradation pathway in halophiles. The extremely halophilic bacteria Arhodomonas sp. strain Seminole and Arhodomonas sp. strain Rozel, which degrade benzene and toluene as the sole carbon source at high salinity (0.5 to 4 M NaCl), were isolated from enrichments developed from contaminated hypersaline environments. To obtain insights into the physiology of this novel group of organisms, a draft genome sequence of the Seminole strain was obtained. A cluster of 13 genes predicted to be functional in the hydrocarbon degradation pathway was identified from the sequence. Two-dimensional (2D) gel electrophoresis and liquid chromatography-mass spectrometry were used to corroborate the role of the predicted open reading frames (ORFs). ORFs 1080 and 1082 were identified as components of a multicomponent phenol hydroxylase complex, and ORF 1086 was identified as catechol 2,3-dioxygenase (2,3-CAT). Based on this analysis, it was hypothesized that benzene is converted to phenol and then to catechol by phenol hydroxylase components. The resulting catechol undergoes ring cleavage via the meta pathway by 2,3-CAT to form 2-hydroxymuconic semialdehyde, which enters the tricarboxylic acid cycle. To substantiate these findings, the Rozel strain was grown on deuterated benzene, and gas chromatography-mass spectrometry detected deuterated phenol as the initial intermediate of benzene degradation. These studies establish the initial steps of the benzene degradation pathway in halophiles. PMID:22885747

  16. Formation of reactive metabolites from benzene

    Rat liver mitoplasts were incubated first with [3H]dGTP, to form DNA labeled in G, and then with [14C]benzene. The DNA was isolated and upon isopycnic density gradient centrifugation in CsCl yielded a single fraction of DNA labeled with both [3H] and [14C]. These data are consistent with the covalent binding of one or more metabolites of benzene to DNA. The DNA was enzymatically hydrolyzed to deoxynucleosides and chromatographed to reveal at least seven deoxyguanosine adducts. Further studies with labeled deoxyadenine revealed one adduct on deoxyadenine. [3H]Deoxyguanosine was reacted with [14C]hydroquinone or benzoquinone. The product was characterized using uv, fluorescence, mass and NMR spectroscopy. A proposed structure is described. (orig.)

  17. One Million Quantum States of Benzene.

    Halverson, Thomas; Poirier, Bill

    2015-12-17

    In this study, we compute all of the dynamically relevant vibrational quantum states of benzene, using an "exact" quantum dynamics (EQD) methodology. Benzene (C6H6), in addition to being a very large molecule for EQD (12 atoms, 30 vibrational modes), also has a very large number of vibrational states-around 10(6) in all, lying within 6500 cm(-1) of the ground state. The EQD methodology developed here uses a phase space picture to optimize the truncation of a harmonic oscillator basis-not only with respect to the molecular system of interest but also with respect to the targeted spectral range. By employing several such EQD calculations, targeted to different spectral ranges, a "hybridized" data set is constructed that provides the most accurate results everywhere. In particular, more than 500?000 states are converged to 15 cm(-1) or better. PMID:26418314

  18. Metabolites formed during anaerobic transformation of toluene and o-xylene and their proposed relationship to the initial steps of toluene mineralization.

    Evans, P J; Ling, W.; Goldschmidt, B; Ritter, E R; Young, L Y

    1992-01-01

    Strain T1 is a facultative bacterium that is capable of anaerobic toluene degradation under denitrifying conditions. While 80% of the carbon from toluene is either oxidized to carbon dioxide or assimilated into cellular carbon, a significant portion of the remainder is transformed into two dead-end metabolites. These metabolites were produced simultaneous to the mineralization of toluene and were identified as benzylsuccinic acid and benzylfumaric acid. Identification was based on comparison ...

  19. Nonlinear diffusion in Acetone-Benzene Solution

    Obukhovsky, Vjacheslav V

    2010-01-01

    The nonlinear diffusion in multicomponent liquids under chemical reactions influence has been studied. The theory is applied to the analysis of mass transfer in a solution of acetone-benzene. It has been shown, that the creation of molecular complexes should be taken into account for the explanation of the experimental data on concentration dependence of diffusion coefficients. The matrix of mutual diffusivities has been found and effective parameters of the system have been computed.

  20. Facile preparation of sphere-like copper ferrite nanostructures and their enhanced visible-light-induced photocatalytic conversion of benzene

    Graphical abstract: - Highlights: • Spinel CuFe2O4 nanospheres were successfully synthesized via a facile method. • CuFe2O4 nanospheres showed high photocatalytic activity toward benzene. • Ethyl acetate, carboxylic acid and aldehyde were the intermediate products. - Abstract: Spinel copper ferrite nanospheres with diameters of about 116 nm were synthesized in high yield via a facile solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size uniformity and regularity. The band-gap energy of CuFe2O4 nanospheres was calculated to be about 1.69 eV, indicating their potential visible-light-induced photocatalytic activity. The dramatically enhanced photocatalytic activity of the CuFe2O4 nanospheres was evaluated via the photocatalytic conversion of benzene under Xe lamp irradiation. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO2 was produced as the final product during the reaction process. This study provided new insight into the design and preparation of functional nanomaterials with sphere structure in high yield, and the as-grown architectures demonstrated an excellent ability to remove organic pollutants in the atmosphere

  1. Facile preparation of sphere-like copper ferrite nanostructures and their enhanced visible-light-induced photocatalytic conversion of benzene

    Shen, Yu, E-mail: shenyuqing0322@gmail.com [School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Wu, Yanbo; Xu, Hongfeng; Fu, Jie [School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Li, Xinyong; Zhao, Qidong; Hou, Yang [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China)

    2013-10-15

    Graphical abstract: - Highlights: Spinel CuFe{sub 2}O{sub 4} nanospheres were successfully synthesized via a facile method. CuFe{sub 2}O{sub 4} nanospheres showed high photocatalytic activity toward benzene. Ethyl acetate, carboxylic acid and aldehyde were the intermediate products. - Abstract: Spinel copper ferrite nanospheres with diameters of about 116 nm were synthesized in high yield via a facile solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size uniformity and regularity. The band-gap energy of CuFe{sub 2}O{sub 4} nanospheres was calculated to be about 1.69 eV, indicating their potential visible-light-induced photocatalytic activity. The dramatically enhanced photocatalytic activity of the CuFe{sub 2}O{sub 4} nanospheres was evaluated via the photocatalytic conversion of benzene under Xe lamp irradiation. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO{sub 2} was produced as the final product during the reaction process. This study provided new insight into the design and preparation of functional nanomaterials with sphere structure in high yield, and the as-grown architectures demonstrated an excellent ability to remove organic pollutants in the atmosphere.

  2. Electronic structure of the benzene dimer cation

    Pieniazek, Piotr A.; Krylov, Anna I.; Bradforth, Stephen E.

    2007-07-01

    The benzene and benzene dimer cations are studied using the equation-of-motion coupled-cluster model with single and double substitutions for ionized systems. The ten lowest electronic states of the dimer at t-shaped, sandwich, and displaced sandwich configurations are described and cataloged based on the character of the constituent fragment molecular orbitals. The character of the states, bonding patterns, and important features of the electronic spectrum are explained using qualitative dimer molecular orbital linear combination of fragment molecular orbital framework. Relaxed ground state geometries are obtained for all isomers. Calculations reveal that the lowest energy structure of the cation has a displaced sandwich structure and a binding energy of 20kcal/mol, while the t-shaped isomer is 6kcal/mol higher. The calculated electronic spectra agree well with experimental gas phase action spectra and femtosecond transient absorption in liquid benzene. Both sandwich and t-shaped structures feature intense charge resonance bands, whose location is very sensitive to the interfragment distance. Change in the electronic state ordering was observed between ? and ?u states, which correlate to the B and C bands of the monomer, suggesting a reassignment of the local excitation peaks in the gas phase experimental spectrum.

  3. Catalytic performance of the exchanged Y faujasites by Ce3+, La3+, UO22+, Co2+, Sr2+, Pb2+, Tl+ and NH4+ cations in the disproportionation reaction of toluene

    The catalytic performance of exchanged Y faujasites by Ce3+, La3+, UO22+, Co2+, Sr2+, Pb2+, Tl+ and NH4+ ions were studied in a disproportionation reaction in the gaseous phase. It was shown that total acidity generated by exchanged ions is responsible of the catalytic activity. Rare earths (cerium, lanthanum and uranium) catalysts have appreciable performance and allowed one to obtain an important xylenes proportion at 400 to 450 C. The decrease of xylenes and trimethyl-benzenes proportion in studied catalysts shows the implication of xylenes in toluene disproportionation reaction. (authors)

  4. PROCESS SIMULATION OF BENZENE SEPARATION COLUMN OF LINEAR ALKYL BENZENE (LABPLANT

    Zaid A. AbdelRahman

    2013-05-01

    Full Text Available       CHEMCAD process simulator was used for the analysis of existing benzene separation column in LAB plant(Arab Detergent Company/Beiji-Iraq.         Simulated column performance curves were constructed. The variables considered in this study are the thermodynamic model option, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates compositions, were constructed. Four different thermodynamic models options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.            For Benzene Column (32 real stages, feed stage 14, the simulated results show that bottom temperature above 200 oC the weight fractions of top components, except benzene, increases sharply, where as benzene top weight fraction decreasing sharply. Also, feed temperature above 180 oC  shows same trends. The column profiles remain fairly constant from tray 3 (immediately below condenser to tray 10 (immediately above feed and from tray 15 (immediately below feed to tray 25 (immediately above reboiler. Simulation of the benzene separation column in LAB production plant using CHEMCAD simulator, confirms the real plant operation data. The study gives evidence about a successful simulation with CHEMCAD.

  5. Solid acid catalysed formation of ethyl levulinate and ethyl glucopyranoside from mono- and disaccharides

    Shunmugavel, Saravanamurugan; Riisager, Anders

    2012-01-01

    Sulfonic acid functionalised SBA-15 (SO3H-SBA-15), sulfated zirconia and beta, Y, ZSM-5 and mordenite zeolite catalysts have been applied for the dehydration of sugars to ethyl levulinate and ethyl-D-glucopyranoside (EDGP) using ethanol as solvent and reactant. The SO3H-SBA-15 catalyst showed a...... high catalytic activity for the selective conversion of fructose to ethyl levulinate (57%) and glucose to EDGP (80%) at 140 °C, whereas the disaccharide sucrose yielded a significant amount of both products. The SO3H-SBA-15 catalysts were found to be highly active compared to the zeolites under...

  6. Crystal structure of ethyl 2-(2,4,5-trimethoxyphenylquinoline-4-carboxylate

    T. O. Shrungesh Kumar

    2015-07-01

    Full Text Available In the title compound, C21H21NO5, the dihedral angle between the quinoline ring system (r.m.s. deviation = 0.028? and the trimethoxybenzene ring is 43.38?(5. The C atoms of the methoxy groups deviate from their attached benzene ring by ?0.396?(2, ?0.049?(2 and 0.192?(2? for the ortho-, meta- and para-substituents, respectively. The pendant ethyl chain is disordered over two orientations in a 0.527?(5:0.473?(5 ratio. A short intramolecular CH...O contact closes an S(6 ring. In the crystal, inversion dimers linked by pairs of weak CH...O interactions generate R22(6 loops. The dimers are linked by further CH...O interactions to generate [1-10] chains.

  7. Kinetics of gas-phase pyrolysis of ethyl-substituted bis-arene compounds of molybdenum

    Kinetics is studied of gas-phase pyrolysis of molybdenum individual ?-complexes: bis-diethylbenzenemolybdenum and ethylbenzenediethylbenzenemolybdenum. Pyrolysis has been studied by the manometric method under static conditions. The pyrolysis of molybdenum ?-complexes is described by the kinetic equation of the first order reaction in the temperature range of 340-400 deg and in the pressure range of 74-178 mm Hg. Homogeneous-heterogeneous type of the process is shown. The increase of a number of ethyl substituents in a ligand benzene ring lightly influence the thermostability of these compounds. The regularities of molybdenum filming by the pyrolysis of molybdenum ?-complex mixture are studied. The optimum regime of filming is found: the temperature equals 400 deg; the evaporator temperature equals 100 deg. The merits of these films in comparison with the molybdenum ones obtained during the vacuum spraying are shown

  8. 2-Ethyl-6-methylanilinium 4-methylbenzenesulfonate

    Jiao Ye

    2009-02-01

    Full Text Available The title compound, C9H14N+·C7H7SO3−, contains a 2-ethyl-6-methylanilinium cation and a 4-methylbenzenesulfonic anion. The cations are anchored between the anions through N—H...O hydrogen bonds. Electrostatic and van der Waals interactions, as well as hydrogen bonds, maintain the structural cohesion.

  9. At-line benzene monitor for measuring benzene in precipitate hydrolysis aqueous

    A highly accurate and repeatable at-line benzene monitor (ALBM) has been developed to measure the benzene concentration in precipitate hydrolysis aqueous (PHA) in the DWPF. This analyzer was conceived and jointly developed within SRTC by the Analytical Development and the Defense Waste Process Technology Sections with extensive support from the Applied Statistics Group and the TNX Operations Section. It is recommended that an ALBM specifically adapted to DWPF analytical requirements be used to measure benzene in PHA; calibrations be performed using a 10% methanol solution matrix (for standard stability); and based on experience gained in development at TNX, the services of ADS and ASG be employed to both adapt the ALBM to DWPF requirements and develop statistical control procedures

  10. At-line benzene monitor for measuring benzene in precipitate hydrolysis aqueous

    Jenkins, W.J.

    1992-10-14

    A highly accurate and repeatable at-line benzene monitor (ALBM) has been developed to measure the benzene concentration in precipitate hydrolysis aqueous (PHA) in the DWPF. This analyzer was conceived and jointly developed within SRTC by the Analytical Development and the Defense Waste Process Technology Sections with extensive support from the Applied Statistics Group and the TNX Operations Section. It is recommended that an ALBM specifically adapted to DWPF analytical requirements be used to measure benzene in PHA; calibrations be performed using a 10% methanol solution matrix (for standard stability); and based on experience gained in development at TNX, the services of ADS and ASG be employed to both adapt the ALBM to DWPF requirements and develop statistical control procedures.

  11. Total oxidation of toluene over calcined trimetallic hydrotalcites type catalysts

    Palacio, Luz A. [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Grupo Catalizadores y Adsorbentes, Universidad de Antioquia 1-317, A.A. 1226 Medellin (Colombia); Velasquez, Juliana; Echavarria, Adriana [Grupo Catalizadores y Adsorbentes, Universidad de Antioquia 1-317, A.A. 1226 Medellin (Colombia); Faro, Arnaldo [Departamento de Fisicoquimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Ilha do Fundao, CT bloco A, Rio de Janeiro (Brazil); Ramoa Ribeiro, F. [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ribeiro, M. Filipa, E-mail: filipa.ribeiro@ist.utl.pt [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2010-05-15

    Two trimetallic ZnCuAl and MnCuAl hydrotalcites have been successfully synthesized by a co-precipitation method. The manganese based material was identified as a new hydrotalcite phase. Both lamellar precursors were calcined at 450 and 600 deg. C and the resulting catalysts were tested on reaction of total oxidation of toluene. The solids were characterized by X-ray diffraction, thermal analysis, atomic absorption spectroscopy, Fourier transformed infrared spectroscopy, N{sub 2} adsorption and H{sub 2} temperature-programmed reduction. It was found that ZnCuAl materials are composed of copper and zinc oxides supported on alumina; while MnCuAl ones comprise basically spinel phases, which were not completely identified. The catalytic behavior of the calcined samples showed that Mn hydrotalcite calcined at 450 deg. C exhibited the best catalytic performance that corresponds to 100% toluene conversion into CO{sub 2} at about 300 deg. C.

  12. Use of modified clay materials in toluene conversion

    Clay materials, montmorillonite from Maghniya deposits (Algeria), were used as an acidic catalyst in toluene conversion. Toluene disproportionation reaction in gaseous phase was used. These clays were modified by ion exchange with uranyl ions UO22+. The surface acidity of catalysts was determined by the stepwise desorption technique (STD) of probe molecules using butylamine and ammonia. Thus, total acidity and distribution of the acidity strength were determined. The results show that materials presented an appreciable total acidity and catalytic activity in studied reaction. The acidity strength of catalysts due to UO22+ ions was kept at a temperature of 550 C. A relationship was found between the catalytic activity and acidity strength generated by the introduction of uranyl ions in the clay structure. (authors)

  13. Total oxidation of toluene over calcined trimetallic hydrotalcites type catalysts

    Two trimetallic ZnCuAl and MnCuAl hydrotalcites have been successfully synthesized by a co-precipitation method. The manganese based material was identified as a new hydrotalcite phase. Both lamellar precursors were calcined at 450 and 600 deg. C and the resulting catalysts were tested on reaction of total oxidation of toluene. The solids were characterized by X-ray diffraction, thermal analysis, atomic absorption spectroscopy, Fourier transformed infrared spectroscopy, N2 adsorption and H2 temperature-programmed reduction. It was found that ZnCuAl materials are composed of copper and zinc oxides supported on alumina; while MnCuAl ones comprise basically spinel phases, which were not completely identified. The catalytic behavior of the calcined samples showed that Mn hydrotalcite calcined at 450 deg. C exhibited the best catalytic performance that corresponds to 100% toluene conversion into CO2 at about 300 deg. C.

  14. (Liquid + liquid) equilibria for ternary mixtures of (alkane + benzene + [EMpy] [ESO4]) at several temperatures and atmospheric pressure

    In this work, the separation of benzene from aliphatic hydrocarbons (hexane, or heptane) is investigated by extraction with 1-ethyl-3-methylpyridinium ethylsulphate ionic liquid, [EMpy][ESO4]. (Liquid + liquid) equilibria (LLE) data are determined for the ternary systems: {hexane (1) + benzene (2) + [EMpy][ESO4] (3)} at T = (283.15, 293.15, 298.15, and 303.15) K and {heptane (1) + benzene (2) + [EMpy][ESO4] (3)} at T = (283.15 and 298.15) K and atmospheric pressure. The selectivity and distribution coefficient, derived from the tie line data, were used to determine whether the ionic liquid is a good solvent for the extraction of aromatic from aliphatic compounds. The consistency of the tie line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL equation. A study of the temperature effect and the influence of the chain length of the alkanes were realized. The results obtained were compared with other ionic liquids. There are no literature data for the mixtures discussed in this paper.

  15. (Liquid + liquid) equilibria for ternary mixtures of (alkane + benzene + [EMpy] [ESO{sub 4}]) at several temperatures and atmospheric pressure

    Gonzalez, Emilio J.; Calvar, Noelia; Gonzalez, Begona [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain); Dominguez, Angeles [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain)], E-mail: admguez@uvigo.es

    2009-11-15

    In this work, the separation of benzene from aliphatic hydrocarbons (hexane, or heptane) is investigated by extraction with 1-ethyl-3-methylpyridinium ethylsulphate ionic liquid, [EMpy][ESO{sub 4}]. (Liquid + liquid) equilibria (LLE) data are determined for the ternary systems: {l_brace}hexane (1) + benzene (2) + [EMpy][ESO{sub 4}] (3){r_brace} at T = (283.15, 293.15, 298.15, and 303.15) K and {l_brace}heptane (1) + benzene (2) + [EMpy][ESO{sub 4}] (3){r_brace} at T = (283.15 and 298.15) K and atmospheric pressure. The selectivity and distribution coefficient, derived from the tie line data, were used to determine whether the ionic liquid is a good solvent for the extraction of aromatic from aliphatic compounds. The consistency of the tie line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL equation. A study of the temperature effect and the influence of the chain length of the alkanes were realized. The results obtained were compared with other ionic liquids. There are no literature data for the mixtures discussed in this paper.

  16. Analysis of a Recent Biofilter Model for Toluene Biodegradation

    Muhammad Qasim; Zarook Shareefdeen

    2013-01-01

    This paper investigates and provides a critical analysis of the toluene biofilter model developed by Li and De Visscher. The model simulation results have been reproduced and compared with several sets of experimental data from literature. Three different model variations are considered: model with no substrate inhibition, with substrate inhibition, and with air flow rate modification. A sensitivity analysis has been performed on model to study the effect of important parameters on the remov...

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

    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 (R4N)i[Ln(NO3)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

  18. Eco friendly nitration of toluene using modified zirconia

    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  |

  19. Viscometric study of high-cis polybutadiene in toluene solution

    Mello Ivana L.; Delpech Marcia C.; Coutinho Fernanda M. B.; Albino Fernanda F. M.

    2006-01-01

    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-Saku...

  20. Simultaneous biodegradation of chlorobenzene and toluene by a Pseudomonas strain.

    Pettigrew, C A; Haigler, B E; Spain, J. C.

    1991-01-01

    Pseudomonas sp. strain JS6 grows on a wide range of chloro- and methylaromatic substrates. The simultaneous degradation of these compounds is prevented in most previously studied isolates because the catabolic pathways are incompatible. The purpose of this study was to determine whether strain JS6 could degrade mixtures of chloro- and methyl-substituted aromatic compounds. Strain JS6 was maintained in a chemostat on a minimal medium with toluene or chlorobenzene as the sole carbon source, sup...

  1. Toluene nitration in irradiated nitric acid and nitrite solution

    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.

  2. Toluene nitration in irradiated nitric acid and nitrite solutions

    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. ADSORPTION OF TOLUENE ONTO BLEACHED EUCALYPTUS PULP TREATED WITH ULTRASOUND

    Iñaki Urruzola,

    2012-07-01

    Full Text Available Bleached kraft semichemical eucalyptus pulp was used as raw material to adsorb an organic compound, toluene, from aqueous solution. The pulp was sonicated with different powers and different times to obtain smaller cellulose fibers. The adsorption capacity for toluene of sonicated fibers and bleached eucalyptus pulp was measured by ultraviolet spectroscopy. The absorption capacity for toluene was increased considerably when cellulose nanofibres were obtained. The adsorption capacity of bleached eucalyptus pulp was 36 μmol/g, while sonicated fibres at 30 W and 20 hours increased the adsorption by 47% and at 50 W and 20 h increased it by 67% compared with untreated fibres. Visual examination and optical microscopy were used to observe the reduction of fibers width and the dispersion increase. Contact angle measurements were used to analyze the variation of hydrophilic character of cellulose. Fourier transform infrared spectroscopy was used to study variations introduced by the ultrasound treatments on the chemical structure of the samples. The adsorption capacity studies showed that the treatment with ultrasound improved the retention capacity of the fibres, increasing considerably the adsorption capacity when the fiber width approached the nanoscale.

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

    Bælum, Jesper; Døssing, M; Hansen, S H; Lundqvist, G R; Andersen, N T

    1987-01-01

    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.......90 +/- 1.85 g/g cr) during the last 3 h of exposure to 100 ppm toluene. The corresponding figures for O-cr were 0.05 +/- 0.05 micrograms/min (0.08 +/- 0.14 mg/g cr), and 2.04 +/- 0.84 micrograms/min (2.05 +/- 1.18 mg/g cr). The individual creatinine excretion rate was considerably influenced by sex, body...... weight and smoking habits, thus influencing the metabolite concentration standardised in relation to creatinine. It is concluded that both metabolites are estimates of toluene exposure. O-cr is more specific than HA, but the individual variation in excretion of both metabolites is large, and when...

  5. 21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials,...

  6. Crystal structure of (E-4-{4-[ethyl(2-hydroxyethylamino]styryl}-1-methylpyridinium nitrate hemihydrate

    Hui Zhang

    2015-02-01

    Full Text Available The asymmetric unit of the title compound, C18H23N2O+·NO3−·0.5H2O, contains two independent 4-{4-[ethyl(2-hydroxyethylamino]styryl}-1-methylpyridin-1-ium cations, two nitrate anions and one lattice water molecule. In the cations, the pyridine ring is twisted with respect by 7.98 (12 and 18.42 (10° to the benzene ring. In the crystal, the cations, the anions and the lattice water molecules are linked by O—H...O hydrogen bonds and weak C—H...O hydrogen bonds, forming a three-dimensional supramolecular architecture. π–π stacking occurs between pyridine and benzene rings of adjacent cations, the centroid–centroid distances being 3.8169 (15 and 3.8663 (14 Å. In the crystal, one of the independent cations is disordered, the central vinyl unit and the terminal hydroxylethyl group being disordered over two sets of sites with site occupancy factors of 0.600 (6 and 0.400 (6.

  7. Benzene, the Exposome and Future Investigations of Leukemia Etiology

    Smith, Martyn T.; ZHANG, LUOPING; Cliona M. McHale; Skibola, Christine F; Stephen M Rappaport

    2011-01-01

    Benzene exposure is associated with acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and probably lymphoma and childhood leukemia. Biological plausibility for a causal role of benzene in these diseases comes from its toxicity to hematopoietic stem cells (HSC) or progenitor cells, from which all leukemias and related disorders arise. The effect of this toxicity is manifest as lowered blood counts (hematotoxicity), even in individuals occupationally exposed to low levels of benzen...

  8. Draft Genome Sequence of Uncultivated Toluene-Degrading Desulfobulbaceae Bacterium Tol-SR, Obtained by Stable Isotope Probing Using [13C6]Toluene

    Abu Laban, Nidal; Tan, BoonFei; Dao, Anh; Foght, Julia

    2015-01-01

    The draft genome of a member of the bacterial family Desulfobulbaceae (phylum Deltaproteobacteria) was assembled from the metagenome of a sulfidogenic [13C6]toluene-degrading enrichment culture. The “Desulfobulbaceae bacterium Tol-SR” genome is distinguished from related, previously sequenced genomes by suites of genes associated with anaerobic toluene metabolism, including bss, bbs, and bam.

  9. 2-{2,4,6-Tris(bromomethyl-3,5-bis[(1,3-dioxoisoindolin-2-ylmethyl]benzyl}isoindoline-1,3-dione toluene monosolvate

    Niklas Koch

    2014-04-01

    Full Text Available In the title compound, C36H24Br3N3O6·C7H8, the toluene solvent molecule is associated with the receptor molecule via C—H...π bonding. The planes of the phthalimido groups are inclined at 77.0 (1, 63.0 (1 and 77.8 (1° with respect to the benzene ring. The molecular conformation is stabilized by C—H...O and C—H...Br hydrogen bonds. The crystal structure features non-classical hydrogen bonds of the C—H...N, C—H...O and C—H...Br type, leading to a three-dimensional cross-linking of molecules. The pattern of non-covalent intermolecular bonding is completed by O...Br halogen bonds [3.306 (3 Å], which link the receptor molecules into infinite strands extending along the a-axis direction.

  10. Accumulation of chlorinated benzenes in earthworms

    Beyer, W.N.

    1996-01-01

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. This paper describes a long-term (26 week) experiment relating the concentrations of chlorinated benzenes in earthworms to 1) the length of exposure, and it describes three 8-week experiments relating concentrations of chlorinated benzenes in earthworms to 2) their concentration in soil 3) the soil organic matter content and, 4) the degree of chlorination. In the 26-week experiment, the concentration of 1,2,4 - trichlorobenzene in earthworms fluctuated only slightly about a mean of 0.63 ppm (Fig. 1). Although a statistically significant decrease can be demonstrated over the test (Pearson correlation coefficient, r = -0.62 p earthworms showed a cyclical trend that coincided with replacement of the media, and a slight but statistically significant tendency to increase from about 2 to 3 ppm over the 26 weeks (r = 0.55, p earthworms increased as the concentrations in the soil increased (Fig. 2), but leveled off at the highest soil concentrations. The most surprising result of this study was the relatively low concentrations in earthworms compared to those in soils. The average concentration of each of the six isomers of trichlorobenzene and tetrachlorobenzene in earthworms was only about 1 ppm (Table 2); the isomeric structure did not affect accumulation. The concentration of organic matter in soil had a prominent effect on hexachlorobenzene concentrations in earthworms (Fig. 3). Hexachlorobenzene concentrations decreased steadily from 9.3 ppm in earthworms kept in soil without any peat moss added to about 1 ppm in soil containing 16 or 32% organic matter.

  11. Crystal structures of ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate.

    Gomes, Ligia R; Low, John Nicolson; Fernandes, Carlos; Gaspar, Alexandra; Borges, Fernanda

    2016-01-01

    The crystal structures of two chromone derivatives, viz. ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate, C19H16O4, (1), and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate C18H13FO4, (2), have been determined: (1) crystallizes with two mol-ecules in the asymmetric unit. A comparison of the dihedral angles beween the mean planes of the central chromone core with those of the substituents, an ethyl ester moiety at the 2-position and a para-substituted phenyl ring at the 6-position shows that each mol-ecule differs significantly from the others, even the two independent mol-ecules (a and b) of (1). In all three mol-ecules, the carbonyl groups of the chromone and the carboxyl-ate are trans-related. The supra-molecular structure of (1) involves only weak C-H⋯π inter-actions between H atoms of the substituent phenyl group and the phenyl group, which link mol-ecules into a chain of alternating mol-ecules a and b, and weak π-π stacking inter-actions between the chromone units. The packing in (2) involves C-H⋯O inter-actions, which form a network of two inter-secting ladders involving the carbonyl atom of the carboxyl-ate group as the acceptor for H atoms at the 7-position of the chromone ring and from an ortho-H atom of the exocyclic benzene ring. The carbonyl atom of the chromone acts as an acceptor from a meta-H atom of the exocyclic benzene ring. π-π inter-actions stack the mol-ecules by unit translation along the a axis. PMID:26870574

  12. (Z-6-{2-[(E-2,4-Dihydroxybenzylideneamino]phenylaminomethylene}-3-hydroxycyclohexa-2,4-dienone toluene solvate

    Hasan Zargoshi

    2008-09-01

    Full Text Available The bis-Schiff base title compound, C20H16N2O4·C7H8, crystallized as a toluene solvate. In the solid state, it is present as its prototropic tautomer formed by transfer of one of the ortho-hydroxyl H atoms. The proton transfer is accompanied by a shift of electron pairs, as is evident from the observed C—O and C—N bond distances of 1.305 (2 and 1.315 (2 Å, which are largely consistent with C=O and C—N distances. The actual molecule present in the solid state is thus the charge-neutral β-keto amine, with a small contribution of its zwitterionic valence tautomer via partial delocalization of electron pairs along the N—C—C—C—O atom chain. The dihedral angles between the central benzene ring and the two outer benzene rings of the Schiff base are 51.99 (8 and 12.95 (9°. Intramolecular O—H...N and N—H...O hydrogen bonds generate S(6 ring motifs, whereas intramolecular N—H...N hydrogen bonds generate S(5 ring motifs. In the crystal structure, O—H...O hydrogen bonds and weak C—H...O interactions link the molecules into one-dimensional zigzag chains along the b axis; these chains are further stacked by O—H...O and weak C—H...O interactions along the c axis, forming two-dimensional extended networks parallel to the bc plane. In addition, the crystal structure is further stabilized by weak C—H...π and π–π interactions.

  13. Supported manganese oxide on TiO2 for total oxidation of toluene and polycyclic aromatic hydrocarbons (PAHs): Characterization and catalytic activity

    Manganese oxide catalysts supported on titania (TiO2) were prepared by incipient wetness impregnation method in order to elaborate catalysts for total oxidation of toluene and PAHs. These catalysts have been characterized by means of X-ray diffraction (XRD), electron paramagnetic resonance (EPR), temperature programmed reduction (TPR) and temperature programmed desorption (TPD). It has been shown that for the 5%Mn/TiO2 catalyst the reducibility and the mobility of oxygen are higher compared, in one side, to other x%Mn/TiO2 samples and, in another side, to catalysts where TiO2 support was replaced by γ-Al2O3 or SiO2. It has been shown that the content of manganese loading on TiO2 has an effect on the catalytic activity in the toluene oxidation. A maximum of activity was obtained for the 5%Mn/TiO2 catalyst where the total conversion of toluene was reached at 340 °C. This activity seems to be correlated to the presence of the Mn3+/Mn4+ redox couple in the catalyst. When the Mn content increases, large particles of Mn2O3 appear leading then to the decrease in the corresponding activity. In addition, compared to both other supports, TiO2 seems to be the best to give the best catalytic activity for the oxidation of toluene when it is loaded with 5% of manganese. For this reason, the latter catalyst was tested for the abatement of some PAHs. The light off temperature of PAHs compounds increases with increasing of benzene rings number and with decreasing of H/C ratio. All of PAHs are almost completely oxidized and converted at temperatures lower than 500 °C. - Highlights: • Preparation of x%MnO2/TiO2 catalysts. • Catalytic oxidation tests of toluene and PAHs. • EPR, TPR and TPD characterizations of Mn(II) and Mn(IV) ions

  14. Protective effects of quercetine on the neuronal injury in frontal cortex after chronic toluene exposure.

    Kanter, Mehmet

    2013-08-01

    The aim of this study was designed to evaluate the possible protective effects of quercetine (QE) on the neuronal injury in the frontal cortex after chronic toluene exposure in rats. The rats were randomly allotted into one of the three experimental groups, namely, groups A (control), B (toluene treated) and C (toluene-treated with QE), where each group contains 10 animals. Control group received 1 ml of normal saline solution, and toluene treatment was performed by the inhalation of 3000 ppm toluene in an 8-h/day and 6-day/week order for 12 weeks. The rats in QE-treated group was given QE (15 mg/kg body weight) once a day intraperitoneally for 12 weeks, starting just after toluene exposure. Tissue samples were obtained for histopathological investigation. To date, no histopathological changes of neurodegeneration in the frontal cortex after chronic toluene exposure in rats by QE treatment have been reported. In this study, the morphology of neurons in the QE treatment group was well protected. Chronic toluene exposure caused severe degenerative changes, shrunken cytoplasm and extensively dark picnotic nuclei in neurons of the frontal cortex. We conclude that QE therapy causes morphologic improvement in neurodegeneration of frontal cortex after chronic toluene exposure in rats. We believe that further preclinical research into the utility of QE may indicate its usefulness as a potential treatment on neurodegeneration after chronic toluene exposure in rats. PMID:22252859

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

    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.

  16. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    2010-07-01

    ... average benzene concentration determined? 80.1238 Section 80.1238 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1238 How is a refinery's or importer's average benzene concentration determined? (a) The average benzene concentration of gasoline produced at a refinery or...

  17. Synthesis, spectroscopic, thermal and antimicrobial studies of toluene-3,4-dithiolatoarsenic(III) derivatives with some oxygen and sulphur donor ligands.

    Chauhan, H P S; Bhatiya, Sumit

    2012-11-01

    Replacement reactions of toluene-3,4-dithiolatoarsenic(III) chloride with oxygen and sulphur donor ligands like benzoic acid, thiobenzoic acid, anhydrous sodium acetate, thioacetic acid, phenol, thiophenol, sodium salicylate and thio glycolic acid in 1:1 molar ratio as well as disodium oxalate in 2:1 molar ratio in refluxing anhydrous benzene yielded toluene-3,4-dithiolatoarsenic(III) mono oxo or thio carboxylic or phenolic derivatives of the general formula SC(6)H(3)(CH(3))SAsR {where R=OOCC(6)H(5), SOCC(6)H(5), OOCCH(3), SOCCH(3), OC(6)H(5), SC(6)H(5), OOCC(6)H(4)(OH), SCH(2)COOH} and SC(6)H(3)(CH(3))SAsOOC-COOAsS(CH(3))C(6)H(3)S. These synthesized derivatives are yellow, yellow-brown solids/ liquids and are soluble in common organic solvents like benzene, chloroform, dichloromethane, dimethyl formamide, dimethyl sulphoxide etc. These derivatives have been characterized by melting point determination, molecular weight determination, elemental analysis (C, H, S and As), spectral {UV, IR, NMR ((1)H and (13)C), ESI-Mass, SEM and powder X-ray diffraction} and thermal (TGA, DTA and DSC) studies. Some of these compounds have been screened for their antimicrobial activities using the disc diffusion method. These derivatives have shown good activity as antibacterial and antifungal agents on some selected bacterial and fungal strains, which increased on increasing the concentration. Chloroamphenicol and terbinafin were used as standards for the comparison. PMID:22940048

  18. Ethyl 8,13-dioxa-21-azapentacyclo[18.5.1.02,7.014,19.021,25]hexacosa-2(7,3,5,14,16,18-hexaene-26-carboxylate

    Devadasan Velmurugan

    2013-01-01

    Full Text Available In the title compound, C26H31NO4, the five-membered rings of the central pyrrolizine system adopt N-envelope conformations. The ethyl acetate group adopts an extended conformation. The dihedral angle between the benzene rings is 36.6?(1. In the crystal, CH...O hydrogen bonds form a zigzag chain running along the b-axis directions. The crystal structure is futher consolidated by CH...? interactions.

  19. Clean production of methyl ethyl ketone (MEK)

    Methyl ethyl ketone oxime (MEKO) was obtained by reaction of methyl ethyl ketone (MEK) with ammonia and hydrogen peroxide using titanium silicalite-1 (TS-1) as catalyst. The effect of reaction temperature, type of solvent, molar ratios of NH3/MEK, H2O2/MEK and mg catalyst/mmol MEK ratio was studied. Water was the most appropriate solvent to obtain high selectivity to oxime. 100% selectivity to MEKO and 60% conversion of MEK was obtained at 70 Celsius degrade using the following parameters: H2O2/MEK = 0,7 and NH3/MEK = 1,12. mg.catalyst/mmol MEK = 10,5. Little decrease in the catalytic activity was observed after reusing the catalysts twice suggesting that incorporated Ti in the MFI structure is rather stable under the studied conditions

  20. Ethyl pyruvate decreases HMGB1 release and ameliorates murine colitis.

    Davé, Shaival H; Tilstra, Jeremy S; Matsuoka, Katsuyoshi; Li, Fengling; DeMarco, Richard A; Beer-Stolz, Donna; Sepulveda, Antonia R; Fink, Mitchell P; Lotze, Michael T; Plevy, Scott E

    2009-09-01

    Signals from stressed cells and the enteric microbiota activate macrophages and dendritic cells and mediate intestinal inflammation. HMGB1 serves as an immunogenic stimuli causing release of inflammatory cytokines by myeloid cells. Ethyl pyruvate inhibits secretion of HMGB1 and improves survival in models of endotoxemia and hemorrhagic shock. We reasoned that ethyl pyruvate may be protective in colitis, which involves similar inflammatory pathways. In IL-10(-/-) mice with established chronic colitis, ethyl pyruvate administration ameliorated colitis and reduced intestinal cytokine production. IL-10(-/-) mice demonstrated increased intestinal HMGB1 expression and decreased expression of RAGE compared with wild-type mice. Fecal HMGB1 levels were decreased in ethyl pyruvate-treated mice. Furthermore, ethyl pyruvate induced HO-1 expression in intestinal tissue. In TNBS-induced colitis, intrarectal administration of ethyl pyruvate resulted in amelioration of colitis and reduced intestinal cytokine production. In LPS-activated murine macrophages, ethyl pyruvate decreased expression of IL-12 p40 and NO production but did not affect IL-10 levels. Ethyl pyruvate did not inhibit nuclear translocation of NF-kappaB family members but attenuated NF-kappaB DNA binding. Additionally, ethyl pyruvate induced HO-1 mRNA and protein expression and HO-1 promoter activation. Moreover, ethyl pyruvate prevented nuclear-to-cytoplasmic translocation of HMGB1. In conclusion, the HMGB1/RAGE pathway has pathophysiologic and diagnostic significance in experimental colitis. Ethyl pyruvate and other strategies to inhibit HMGB1 release and function represent promising interventions in chronic inflammatory diseases. PMID:19454652

  1. Continuous ethyl acetate production by Kluyveromyces fragilis on whey permeate

    Kallel-Mhiri, H. (Lab. de Biologie Industrielle et Alimentaire, ENSAIA, 54 - Vandoeuvre-les Nancy (France)); Engasser, J.M. (Lab. de Sciences du Genie Chimique, CNRS-ENSAIA, 54 - Vandoeuvre-les Nancy (France)); Miclo, A. (Lab. de Biologie Industrielle et Alimentaire, ENSAIA, 54 - Vandoeuvre-les Nancy (France))

    1993-11-01

    The synthesis of ethyl acetate by Kluyveromyces fragilis on diluted whey permeate was studied. Ethanol, lactose and O[sub 2] are the direct precursors for ethyl acetate synthesis by this yeast. Ethyl acetate production is affected by many parameters, particularly the carbon/nitrogen (C/N) ratio, Tween 80 and iron. Ethyl acetate synthesis is optimum for C/N = 45. Tween 80 lowered slightly the level of ethyl acetate whereas iron completely stopped ethyl acetate production. The level of ethanol in the feed, the dissolved O[sub 2] (DO) and dilution rate (D) were also optimised. Thus at D = 0.24 h[sup -1], for g/l of ethanol in the feed and 40% DO, the productivity of ethyl acetate was optimal (0.7 g/l per hour). (orig.)

  2. 21 CFR 184.1295 - Ethyl formate.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl formate. 184.1295 Section 184.1295 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... percent in chewing gum as defined in § 170.3(n)(6), hard candy as defined in § 170.3(n)(25), and...

  3. Synthesis of Ethyl Salicylate Using Household Chemicals

    Solomon, Sally; Hur, Chinhyu; Lee, Alan; Smith, Kurt

    1996-02-01

    Ethyl salicylate is synthesized, isolated, and characterized in a three-step process using simple equipment and household chemicals. First, acetylsalicylic acid is extracted from aspirin tablets with isopropyl alcohol, then hydrolyzed to salicylic acid with muriatic acid, and finally, the salicylic acid is esterified using ethanol and a boric acid catalyst. The experiment can be directed towards high school or university level students who have sufficient background in organic chemistry to recognize the structures and reactions that are involved.

  4. 40 CFR 721.3152 - Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

    2010-07-01

    ...-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates (salts). 721.3152 Section 721... Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates... ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

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

    Arcangeli, Jean-Pierre; Arvin, Erik

    The modelling of aerobic biodegradation of toluene and the associated biofilm growth in a fixed biofilm system is presented. The model includes four biomass fractions, three dissolved components, and seven processes. It is assumed that part of the active biomass is composed of filamentous bacteria...... 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...... growth phase 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...

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

    Pedersen, A.R.; Arvin, E.

    1999-01-01

    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...... oligonucleotide 16S ribosomal RNA probe targeting the toluene-degrading species Pseudomonas putida, and by computer simulations (AQUASIM) of the biofilm growth based on a food web model. Biofilms were taken from a lab-scale trickling filter for treatment of toluene-polluted air. The biofilm growth 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...

  7. Mathematical Modeling and Simulation of the Dehydrogenation of Ethyl Benzene to Form Styrene Using Steady-State Fixed Bed Reactor

    Zaidon M. Shakoor

    2013-05-01

    Full Text Available In this research, two models are developed to simulate the steady state fixed bed reactor used for styrene production by ethylbenzene dehydrogenation. The first is one-dimensional model, considered axial gradient only while the second is two-dimensional model considered axial and radial gradients for same variables.The developed mathematical models consisted of nonlinear simultaneous equations in multiple dependent variables. A complete description of the reactor bed involves partial, ordinary differential and algebraic equations (PDEs, ODEs and AEs describing the temperatures, concentrations and pressure drop across the reactor was given. The model equations are solved by finite differences method. The reactor models were coded with Mat lab 6.5 program and various numerical techniques were used to obtain the desired solution.The simulation data for both models were validated with industrial reactor results with a very good concordance.

  8. Highly selective GaN-nanowire/TiO2-nanocluster hybrid sensors for detection of benzene and related environment pollutants

    Aluri, Geetha S.; Motayed, Abhishek; Davydov, Albert V.; Oleshko, Vladimir P.; Bertness, Kris A.; Sanford, Norman A.; Rao, Mulpuri V.

    2011-07-01

    Nanowire-nanocluster hybrid chemical sensors were realized by functionalizing gallium nitride (GaN) nanowires (NWs) with titanium dioxide (TiO2) nanoclusters for selectively sensing benzene and other related aromatic compounds. Hybrid sensor devices were developed by fabricating two-terminal devices using individual GaN NWs followed by the deposition of TiO2 nanoclusters using RF magnetron sputtering. The sensor fabrication process employed standard microfabrication techniques. X-ray diffraction and high-resolution analytical transmission electron microscopy using energy-dispersive x-ray and electron energy-loss spectroscopies confirmed the presence of the anatase phase in TiO2 clusters after post-deposition anneal at 700 C. A change of current was observed for these hybrid sensors when exposed to the vapors of aromatic compounds (benzene, toluene, ethylbenzene, xylene and chlorobenzene mixed with air) under UV excitation, while they had no response to non-aromatic organic compounds such as methanol, ethanol, isopropanol, chloroform, acetone and 1,3-hexadiene. The sensitivity range for the noted aromatic compounds except chlorobenzene were from 1% down to 50 parts per billion (ppb) at room temperature. By combining the enhanced catalytic properties of the TiO2 nanoclusters with the sensitive transduction capability of the nanowires, an ultra-sensitive and selective chemical sensing architecture is demonstrated. We have proposed a mechanism that could qualitatively explain the observed sensing behavior.

  9. Oxidation of aliphatic olefins by toluene dioxygenase: enzyme rates and product identification.

    Lange, C C; Wackett, L. P.

    1997-01-01

    Toluene dioxygenase from Pseudomonas putida F1 has been studied extensively with aromatic substrates. The present work examined the toluene dioxygenase-catalyzed oxidation of various halogenated ethenes, propenes, butenes and nonhalogenated cis-2-pentene, an isomeric mix of 2-hexenes, cis-2-heptene, and cis-2-octene as substrates for toluene dioxygenase. Enzyme specific activities were determined for the more water-soluble C2 to C5 compounds and ranged from

  10. Toluene removal by oxidation reaction in spray wet scrubber: experimental, modeling and optimization

    Roumporn Nikom

    2006-11-01

    Full Text Available Toluene, an important volatile organic compound (VOC, is used in many kinds of industries, such as painting, printing, coating, and petrochemical industries. The emission of toluene causes serious air pollution, odor problem, flammability problem and affects human health. This paper proposes the removal of toluene from waste air using a spray wet scrubber combining the absorption and oxidation reaction. Aqueous sodium hypochlorite (NaOCl solution was used as the scrubbing liquid in the system. NaOCl, the strongest oxidative agent, presents an effective toluene removal. As the scrubbed toluene is reacted, recirculation of the scrubbing liquid could be operated with a constant removal efficiency throughout the operting time. The investigated variables affecting the removal efficiency were air flow rate, inlet toluene concentration, NaOCl concentration, scrubbing liquid flow rate and size of spray nozzle. Influence of the scrubbing parameters was experimentally studied to develop a mathematical model of the toluene removal efficiency. The removal model reveals that the increase of scrubbing liquid flow rate, toluene concentration, and NaOCl concentration together with the decrease of air flow rate and size of spray nozzle can increase the toluene removal efficiency. Optimization problem with an objective function and constraints was set to provide the maximum toluene removal efficiency and solved by Matlab optimization toolbox. The optimization constraints were formed from the mathematical model and process limitation. The solution of the optimization was an air flow rate of 100 m3/h, toluene concentration of 1500 ppm, NaOCl concentration of 0.02 mol/l, NaOCl solution feed rate of 0.8 m3/h, and spray nozzle size of 0.5 mm. Solution of the optimization gave the highest toluene removal efficiency of 91.7%.

  11. Toluene removal by oxidation reaction in spray wet scrubber: experimental, modeling and optimization

    Roumporn Nikom; Juntima Chungsiriporn; Charun Bunyakan

    2006-01-01

    Toluene, an important volatile organic compound (VOC), is used in many kinds of industries, such as painting, printing, coating, and petrochemical industries. The emission of toluene causes serious air pollution, odor problem, flammability problem and affects human health. This paper proposes the removal of toluene from waste air using a spray wet scrubber combining the absorption and oxidation reaction. Aqueous sodium hypochlorite (NaOCl) solution was used as the scrubbing liquid in the syst...

  12. Anaerobic Toluene Activation by Benzylsuccinate Synthase in a Highly Enriched Methanogenic Culture

    Beller, Harry R.; Edwards, Elizabeth A

    2000-01-01

    Permeabilized cells of a highly enriched, toluene-mineralizing, methanogenic culture catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. The specific in vitro rate of benzylsuccinate formation was >85% of the specific in vivo rate of toluene consumption. This is the first report of benzylsuccinate synthase activity in a methanogenic culture; the activity has previously been reported to occur in denitrifying, sulfate-reducing, and anoxygenic photot...

  13. Free radical induction in the brain and liver by products of toluene catabolism

    Mattia, CJ; Adams, JD; Bondy, SC

    1993-01-01

    Toluene and its metabolites have been studied with respect to their reactive oxygen species-enhancing potential in isolated systems and in vivo. The induction of reactive oxygen species (ROS) production was assayed using the probe 2′,7′-dichlorodihydrofluorescin diacetate (DCFH-DA). Intraperitoneal injection of toluene, benzyl alcohol or benzaldehyde caused a significant elevation in the rate of ROS formation within hepatic mitochondrial fractions (P2). In the brain, only toluene induced ROS ...

  14. Electrochemical Oxidation of Toluene on Glassy Carbon Electrodes in Organic Medium

    Luis F. D´Elia; R. Ortíz

    2005-01-01

    The electro-oxidation of toluene in 0.1 M But4NPF6 + CH3CN solutions on glassy carbon electrodes was studied using electrochemical and spectroelectrochemical techniques. Toluene electro-oxidation yields an electrochemical inactive film on the electrode surface. In situ Fourier Transformed Infrared (FTIR) studies suggest the formation of a polymeric film, as the main product, on the surface. Depending on the experimental time scale toluene transformation is a complex reaction that could involv...

  15. Fungal metabolism of toluene: monitoring of fluorinated analogs by (19)F nuclear magnetic resonance spectroscopy

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

    2001-01-01

    We used isomeric fluorotoluenes as model substrates to study the catabolism of toluene by five deuteromycete fungi and one ascomycete fungus capable of growth on toluene as the sole carbon and energy source, as well as by two fungi (Cunninghamella echinulata and Aspergillus niger) that cometabolize toluene. Whole cells were incubated with 2-, 3-, and 4-fluorotoluene, and metabolites were characterized by 19F nuclear magnetic resonance. Oxidation of fluorotoluene by C. echinulata was initiated...

  16. Reported survival with severe mixed acidosis and hyperlactemia after toluene poisoning

    Omar, Amr S; Masood ur Rahman; Said Abuhasna

    2011-01-01

    Lactic acidosis is a recognized complication of the inhalant abuse such as toluene, especially in patients with renal insufficiency. We report a case of severe metabolic acidosis and hyperlactemia due to toluene sniffing. The favorable outcome, despite extremely poor clinical symptoms, signs, laboratory and radiological findings, was unexpected. Specific aspects of the clinical course are addressed. Toluene sniffing should be considered in evaluating sever metabolic acidosis. Favorable outcom...

  17. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    G. Sarwar; K. W. Appel; A. G. Carlton; Mathur, R.; K. Schere; Zhang, R; MAJEED, M.A.

    2010-01-01

    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, northeaste...

  18. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    G. Sarwar; K. W. Appel; A. G. Carlton; Mathur, R.; K. Schere; Zhang, R; MAJEED, M.A.

    2011-01-01

    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, Cle...

  19. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    G. Sarwar; K. W. Appel; A. G. Carlton; Mathur, R.; K. Schere; Zhang, R; MAJEED, M.A.

    2011-01-01

    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, northeaste...

  20. Benzene exposure is associated with epigenetic changes (Review).

    Fenga, Concettina; Gangemi, Silvia; Costa, Chiara

    2016-04-01

    Benzene is a volatile aromatic hydrocarbon solvent and is known as one of the predominant air pollutants in the environment. Chronic exposure to benzene is known to cause aplastic anemia and increased risk of acute myelogenous leukemia in humans. Although the mechanisms by which benzene causes toxicity remain to be fully elucidated, it is widely accepted that its metabolism is crucial to its toxicity, with involvement of one or more reactive metabolites. Novel approaches aimed at evaluating different mechanisms by which benzene can impact on human health by altering gene regulation have been developed. Among these novel approaches, epigenetics appears to be promising. The present review article summarizes the most important findings, reported from the literature, on epigenetic modifications correlated to benzene exposure. A computerized search in PubMed was performed in November 2014, using search terms, including 'benzene', 'epigenetic', 'histone modifications', 'DNA methylation' and 'microRNA'. Epidemiological and experimental studies have demonstrated the potential epigenetic effects of benzene exposure. Several of the epigenomic changes observed in response to environmental exposures may be mechanistically associated with susceptibility to diseases. However, further elucidation of the mechanisms by which benzene alters gene expression may improve prediction of the toxic potential of novel compounds introduced into the environment, and allow for more targeted and appropriate disease prevention strategies. PMID:26936331

  1. 1,4-Bis[(2-pyridylethyliminomethyl]benzene

    Haleden Chiririwa

    2011-04-01

    Full Text Available In the title compound, C22H22N4, the centroid of the benzene ring is located on an inversion centre. The dihedral angle between the benzene and pyridine rings is 10.94 (5°. The crystal structure displays weak intermolecular C—H...N hydrogen bonding and C—H...π interactions.

  2. Benzene as a Chemical Hazard in Processed Foods

    Salviano dos Santos, Vnia Paula; Medeiros Salgado, Andra; Guedes Torres, Alexandre; Signori Pereira, Karen

    2015-01-01

    This paper presents a literature review on benzene in foods, including toxicological aspects, occurrence, formation mechanisms, and mitigation measures and analyzes data reporting benzene levels in foods. Benzene is recognized by the IARC (International Agency for Research on Cancer) as carcinogenic to humans, and its presence in foods has been attributed to various potential sources: packaging, storage environment, contaminated drinking water, cooking processes, irradiation processes, and degradation of food preservatives such as benzoates. Since there are no specific limits for benzene levels in beverages and food in general studies have adopted references for drinking water in a range from 110?ppb. The presence of benzene has been reported in various food/beverage substances with soft drinks often reported in the literature. Although the analyses reported low levels of benzene in most of the samples studied, some exceeded permissible limits. The available data on dietary exposure to benzene is minimal from the viewpoint of public health. Often benzene levels were low as to be considered negligible and not a consumer health risk, but there is still a need of more studies for a better understanding of their effects on human health through the ingestion of contaminated food.

  3. [Benzene in soft drinks: a study in Florence (Italy)].

    Bonaccorsi, Guglielmo; Perico, Andrea; Colzi, Alessio; Bavazzano, Paolo; Di Giusto, Maurizio; Lamberti, Ilaria; Martino, Gianrocco; Puggelli, Francesco; Lorini, Chiara

    2012-01-01

    The aim of this study was to determine the amount of benzene present in soft drinks sold in Florence (Italy). We analyzed 28 different types of soft drinks, by measuring concentrations of benzoic acid, sorbic acid, ascorbic acid (using high performance liquid chromatography with UV detection) and benzene (using gas chromatography and mass spectrometry). Data was analysed by using SPSS 18.0.Traces of benzene were detected in all analyzed beverages, with a mean concentration of 0.45 g/L (range: 0.15-2.36 g/L). Statistically significant differences in mean benzene concentrations were found between beverages according to the type of additive indicated on the drink label, with higher concentrations found in beverages containing both ascorbic acid and sodium benzoate. Two citrus fruit-based drinks were found to have benzene levels above the European limit for benzene in drinking water of 1 g /L. Sodium benzoate and ascorbic acid were also detected in the two drinks.In conclusion, not all soft drink producers have taken steps to eliminate benzoic acid from their soft drinks and thereby reduce the risk of formation of benzene, as recommended by the European Commission. Furthermore, the presence of benzene in trace amounts in all beverages suggests that migration of constituents of plastic packaging materials or air-borne contamination may be occurring. PMID:23073373

  4. Ordered mesoporous carbon film as an effective solid-phase microextraction coating for determination of benzene series from aqueous media

    Jiang, Hui [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Geography Science, Nantong University, Nantong 226001 (China); Li, Jiansheng, E-mail: lijsh@mail.njust.edu.cn [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Jiang, Mingyue; Lu, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Wang, Lianjun, E-mail: wanglj@mail.njust.edu.cn [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2015-08-12

    The present work reports preparation of ordered mesoporous carbon (OMC) film supported on a graphite fiber as a new type of solid-phase microextraction (SPME) fiber for determination of benzene series from aqueous media. The strategy for the supported OMC film preparation was combined dip-coating technology with solvent evaporation-induced self-assembly (EISA) approach. A graphite fiber was immersed in an ethanol solution containing phenolic resin and Pluronic triblock copolymer. Upon solvent evaporation and subsequent pyrolysis under 700 °C, the phenolic resin and the surfactant self-assembled on the surface of the graphite fiber to form smooth OMC film. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen isothermal adsorption results indicate that the resultant OMC film possesses well-ordered two dimensional hexagonal mesostructure with pore diameters of 4.5 nm and BET surfaces of 630 m{sup 2}/g. Scanning electron microscopy (SEM) studies show the supported OMC film with thickness at 8.5 μm is continuous and defect-free. The SPME efficiency of the OMC fiber was evaluated by analysis of five benzene series (benzene, toluene, ethylbenzene, p-xylene and m-xylene) from water samples by gas chromatography-flame ionization detection (GC-FID). The analysis results indicate that the prepared OMC fiber has wide linear ranges (0.5–500 μg/L), low detection limits (0.01–0.05 μg/L) and good repeatabilities (4.0–5.8% for one fiber, 2.9–8.7% for fiber-to-fiber). Compared with commercial counterparts, the OMC fiber exhibits improved extraction efficiency for benzene series and PAHs. - Highlights: • Ordered mesoporous carbon film supported on graphite fiber was first reported as solid-phase microextraction coating. • The strategy for the film preparation was combined dip-coating technology with evaporation-induced self-assembly approach. • The obtained fiber showed enhanced thermal stability and organic solvents resistance. • The fiber outperformed the commercial counterpart on extraction efficiency toward benzene series.

  5. Ordered mesoporous carbon film as an effective solid-phase microextraction coating for determination of benzene series from aqueous media

    The present work reports preparation of ordered mesoporous carbon (OMC) film supported on a graphite fiber as a new type of solid-phase microextraction (SPME) fiber for determination of benzene series from aqueous media. The strategy for the supported OMC film preparation was combined dip-coating technology with solvent evaporation-induced self-assembly (EISA) approach. A graphite fiber was immersed in an ethanol solution containing phenolic resin and Pluronic triblock copolymer. Upon solvent evaporation and subsequent pyrolysis under 700 °C, the phenolic resin and the surfactant self-assembled on the surface of the graphite fiber to form smooth OMC film. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen isothermal adsorption results indicate that the resultant OMC film possesses well-ordered two dimensional hexagonal mesostructure with pore diameters of 4.5 nm and BET surfaces of 630 m2/g. Scanning electron microscopy (SEM) studies show the supported OMC film with thickness at 8.5 μm is continuous and defect-free. The SPME efficiency of the OMC fiber was evaluated by analysis of five benzene series (benzene, toluene, ethylbenzene, p-xylene and m-xylene) from water samples by gas chromatography-flame ionization detection (GC-FID). The analysis results indicate that the prepared OMC fiber has wide linear ranges (0.5–500 μg/L), low detection limits (0.01–0.05 μg/L) and good repeatabilities (4.0–5.8% for one fiber, 2.9–8.7% for fiber-to-fiber). Compared with commercial counterparts, the OMC fiber exhibits improved extraction efficiency for benzene series and PAHs. - Highlights: • Ordered mesoporous carbon film supported on graphite fiber was first reported as solid-phase microextraction coating. • The strategy for the film preparation was combined dip-coating technology with evaporation-induced self-assembly approach. • The obtained fiber showed enhanced thermal stability and organic solvents resistance. • The fiber outperformed the commercial counterpart on extraction efficiency toward benzene series

  6. Vapor–Liquid Equilibrium in Diluted Polymer + Toluene Systems

    Bogdanić, Grozdana; Wichterle, Ivan

    Praha : Česká společnost chemického inženýrství, 2011 - (Halfar, R.), s. 149 ISBN 978-80-905035-0-2. [Konference chemického a procesního inženýrství CHISA 2011 /58./. Srní, Šumava (CZ), 24.10.2011-27.10.2011] R&D Projects: GA ČR GA104/07/0444 Institutional research plan: CEZ:AV0Z40720504 Keywords : polymer and toluene systems * experimental data * vapor–liquid equilibrium data Subject RIV: CF - Physical ; Theoretical Chemistry www.chisa.cz/2011

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

    Bælum, Jesper; Mølhave, Lars; Hansen, Steen Honoré; Væth, Michael

    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......: When the low dose rates were combined, the end exhaled concentrations were at or below the detection limit, while an increase in the dose rate of toluene increased the area under the end exhaled air concentration curve (AUC) of toluene, trichloroethylene, and n-hexane by factors of 44 (16...

  8. Competition in chemostat culture between Pseudomonas strains that use different pathways for the degradation of toluene.

    Duetz, W. A.; C. De Jong; Williams, P. A.; Andel, J.G. van

    1994-01-01

    Pseudomonas putida mt-2, P. cepacia G4, P. mendocina KR1, and P. putida F1 degrade toluene through different pathways. In this study, we compared the competition behaviors of these strains in chemostat culture at a low growth rate (D = 0.05 h-1), with toluene as the sole source of carbon and energy. Either toluene or oxygen was growth limiting. Under toluene-limiting conditions, P. mendocina KR1, in which initial attack is by monooxygenation of the aromatic nucleus at the para position, outco...

  9. Evaluation of simultaneous biodegradation of methane and toluene in landfill covers.

    Su, Yao; Zhang, Xuan; Wei, Xiao-Meng; Kong, Jiao-Yan; Xia, Fang-Fang; Li, Wei; He, Ruo

    2014-06-15

    The biodegradation of CH4 and toluene in landfill cover soil (LCS) and waste biocover soil (WBS) was investigated with a serial toluene concentration in the headspace of landfill cover microcosms in this study. Compared with the LCS sample, the higher CH4 oxidation activity and toluene-degrading capacity occurred in the WBS sample. The co-existence of toluene in landfill gas would positively or negatively affect CH4 oxidation, mainly depending on the toluene concentrations and exposure time. The nearly complete inhibition of toluene on CH4 oxidation was observed in the WBS sample at the toluene concentration of ∼ 80,000 mg m(-3), which was about 10 times higher than that in the LCS sample. The toluene degradation rates in both landfill covers fitted well with the Michaelis-Menten model. These findings showed that WBS was a good alternative landfill cover material to simultaneously mitigate emissions of CH4 and toluene from landfills to the atmosphere. PMID:24801894

  10. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-03-08

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  11. Air pollution monitoring in Como urban areas. Benzene

    This work presents the results of a physical - statistical analysis of concentrations of benzene, measured in the Como Center station from 1996 to 1999. The analysis, conducted by means of the development, by steps, of a multifactorial linear regression model, permitted to find an annual trend of benzene, independently from the influence of meteorologicals variables. It has been seen a decrease of concentrations of benzene, from 1997 to 1999, that may be correlate to a decrease of tenor of benzene in the petrol. At the same time, the results of the model permit to understand the role and the relative weight of different climatic factors on the concentrations of benzene. It has been investigated the presence of daily, weekly and seasonal trend, too

  12. [Update on benzene: from industrial toxicant to environmental carcinogen].

    Manno, Maurizio

    2013-01-01

    Benzene, an industrial chemical myelotoxic at high doses in workers, is now an almost ubiquitous pollutant. It is also a no-threshold genotoxic carcinogen causing acute leukemia and other lymphoaematological tumours. Although its mechanism of action has not been fully clarified, benzene toxicity and carcinogenicity depend on metabolic activation. Polymorphism of activating and detoxifying enzymes (CYP, GST, NQO1) may be critical, therefore, in modulating individual susceptibility to benzene. Further uncertainty factors in assessing low level benzene exposure are the limited sensitivity and specificity of most exposure biomarkers, the frequent coexposure to other volatile organic chemicals (VOC), and the presence of non occupational sources of exposure, such as cigarette smoke and veicular traffic. The aim of this presentation is to introduce the main current critical issues in the risk assessment and the biological monitoring of occupational exposure to benzene at low doses. PMID:24303704

  13. Comparison of hair and nail ethyl glucuronide concentrations

    Ramazan Karanfil

    2014-12-01

    Full Text Available Objective: Alcohol abuse remains to be an important problem in the world. In forensic medicine practice, alcohol and its metabolites should be detected in the body in order to determine whether a person has taken alcohol or not. Therefore, detection of ethyl glucuronide in such keratinous tissues as nails and hair following alcohol intake is important. In the present study, we compared hair ethyl glucuronide concentrations with nail ethyl glucuronide (EtG concentrations. Methods: Hair and nail specimens were obtained from a total of 16 people taking alcohol. The specimens were analyzed with LC/MS/MS technique. Ethyl glucuronide concentrations of hair specimens were compared with those of nail specimens. Results: Ethyl glucuronide concentrations were 1.33-65.67 (+/- SD16.57 ppb in hair specimens and 4.27-225.03 (+/- SD 59.77 ppb in nail specimens. Hair ethyl glucuronide concentrations were correlated with nail ethyl glucuronide concentrations (r=0,808, p<0.001. Conclusion: This study showed that ethyl glucuronide concentrations in hair and nails could be determined. This suggests that detection of nail ethyl glucuronide concentrations can be useful in people without hair. In addition, there was a significant relationship between hair and nail ethyl glucuronide concentrations.

  14. ASPEN HYSYS SIMULATION AND COMPARISON BETWEEN ORGANIC SOLVENTS (SULFOLANE AND DMSO USED FOR BENZENE EXTRACTION

    T. zaiz

    2013-06-01

    Full Text Available Normal 0 false false false EN-US X-NONE AR-SA Due to the high increase of the production of aromatic hydrocarbons: benzene, toluene and xylenes BTX from oil because of the large activity of their big markets especially with the availability of great quantities of these aromatic fractions in the oil. This study has two main parts the first presents a general vision of the aromatic hydrocarbons, the second is going to focus on the liquid-liquid extraction with the selected solvents as a separation method. The solvent selection depends on many properties. In this second part there will be a simulation (conception and execution of the liquid-liquid extraction of aromatics by two different organic solvents Sulfolane and DMSO followed by a comparison between the results obtained by the simulation. The simulator used will be ASPEN HYSYS 7.2. The results of the simulation showed that the use DMSO is better than Sulfolane because of the separation efficiency the economic value and the regeneration rate although its use is more dangerous (more toxic than the Sulfolane

  15. ASPEN HYSYS SIMULATION AND COMPARISON BETWEEN ORGANIC SOLVENTS (SULFOLANE AND DMSO USED FOR BENZENE EXTRACTION

    T. zaiz

    2013-05-01

    Full Text Available Due to the high increase of the production of aromatic hydrocarbons: benzene, toluene and xylenes BTX from oil because of the large activity of their big markets especially with the availability of great quantities of these aromatic fractions in the oil. This study has two main parts the first presents a general vision of the aromatic hydrocarbons, the second is going to focus on the liquid-liquid extraction with the selected solvents as a separation method. The solvent selection depends on many properties. In this second part there will be a simulation (conception and execution of the liquid-liquid extraction of aromatics by two different organic solvents Sulfolane and DMSO followed by a comparison between the results obtained by the simulation. The simulator used will be ASPEN HYSYS 7.2.The results of the simulation showed that the use DMSO is better than Sulfolane because of the separation efficiency the economic value and the regeneration rate although its use is more dangerous (more toxic than the Sulfolane

  16. Health risk equations and risk assessment of airborne benzene homologues exposure to drivers and passengers in taxi cabins.

    Chen, Xiaokai; Feng, Lili; Luo, Huilong; Cheng, Heming

    2016-03-01

    Interior air environment and health problems of vehicles have attracted increasing attention, and benzene homologues (BHs) including benzene, toluene, ethylbenzene, xylenes, and styrene are primary hazardous gases in vehicular cabins. The BHs impact on the health of passengers and drivers in 38 taxis is assessed, and health risk equations of in-car BHs to different drivers and passengers are induced. The health risk of in-car BHs for male drivers is the highest among all different receptors and is 1.04, 6.67, and 6.94 times more than ones for female drivers, male passengers, and female passengers, respectively. In-car BHs could not lead to the non-cancer health risk to all passengers and drivers as for the maximal value of non-cancer indices is 0.41 and is less than the unacceptable value (1.00) of non-cancer health risk from USEPA. However, in-car BHs lead to cancer health risk to drivers as for the average value of cancer indices is 1.21E-04 which is 1.21 times more than the unacceptable value (1.00E-04) of cancer health risk from USEPA. Finally, for in-car airborne benzene concentration (X, μg/m(3)) to male drivers, female drivers, male passengers, and female passengers, the cancer health risk equations are Y = 1.48E-06X, Y = 1.42E-06X, Y = 2.22E-07X, and Y = 2.13E-07X, respectively, and the non-cancer health risk equations are Y = 1.70E-03X, Y = 1.63E-03X, Y = 2.55E-04X, and Y = 2.45E-04X, respectively. PMID:26538262

  17. Ethyl 5-(4-aminophenylisoxazole-3-carboxylate

    Jun-Tao Zhao

    2012-04-01

    Full Text Available The asymmetric unit of the title compound, C12H12N2O3, contains two molecules in which the benzene and isoxazole rings are almost coplanar, the dihedral angles between their mean planes being 1.76 (9 and 5.85 (8°. The two molecules interact with each other via N—H...N and N—H...O hydrogen bonds, which link the molecules into layers parallel to the ac plane. The layers stack in a parallel mode with an interlayer distance of 3.36 (7 Å.

  18. Method for developing a benzene additive

    Patrikeyev, V.V.; Butkov, N.A.; Kutyenev, V.F.; Orlova, K.I.; Tsiguro, T.A.

    1979-11-30

    To improve quality of additive, extract of low viscosity sulphur distillate is oxidated with H/sub 2/O/sub 2/ at a temp. 20-30/sup 0/, in the presence of NSOON with a weight correlation of reagents 1:0.24-0.27:01-0.11, with subsequent treatment of the derived product with 37-40% aqueous formaldehyde at 50-80/sup 0/ in the presence of benzenesulfonic acid with a weight ratio of reagents 1:0.29-0.31:0.12-0.18. This assures binding of metallicgroups to sulphurous compounds which comprise 30-35% of the extract. Cleaning capability, surface tension, appearance of corrosion on steel-3 for benzene AI-93 (B), B+0.1% of the suggested additive, and B+ 0.2% of Labrisol-581 additive comprise, respectively: 30, 240, and 190 min; 40, 19, and 20.2 din/cm, 1.4 and 2.

  19. Methyl tunnelling in trihalogeno-trimethyl-benzenes

    Results of inelastic neutron scattering (INS) from 1,3,5-trihalogeno-2,4,6-trimethyl-benzenes are reported for the chloro-, the bromo- and the iodo-case. For the whole family the spectra show numerous similarities, in the ?eV as well as in the meV range. We observe three tunnelling lines of equal intensity corresponding to three crystallographically inequivalent methyl rotors. The observed librational peaks are at much lower energies than expected from a pure threefold potential. Within the halogen family a systematic reduction of the barrier height is found with larger halogen sizes. The temperature dependence of the tunnelling energies shows the most pronounced difference between TBM and TIM, where the corresponding tunnelling lines even shift in opposite directions. (orig.)

  20. Catalytic combustion of toluene on La perovskites; Combustion catalytique du toluene sur des perovskites a base de La

    Giraudon, J.M.; Nguyen, T.B.; Leclerc, G. [Universite des Sciences et Technologies de Lille, Lab. de Catalyse, UMR 010, 59 - Villeneuve d' Ascq (France); Wyrwalski, F.; Siffert, S.; Aboukais, A.; Lamonier, J.F. [Universite du Littoral-Cote d' Opale, Lab. de Catalyse et Environnement, EA 2598, MREID, 59 - Dunkerque (France)

    2004-07-01

    The aim of this work is to study the chlorine influence on the VOC catalytic combustion process. The LaMO{sub 3} solids (M= Co, Ni, Mn, Fe) have been synthesized and characterized by FTIR, BET, XRD, H{sub 2}-TPR and O{sub 2}-TPD. The toluene oxidation has been carried out in a micro-reactor. After a pretreatment under air (2 L.h{sup -1}) at 350 C during 4 h (1 C.min{sup -1}) and cooling at ambient temperature, the catalyst is put to an air and toluene flux (0.11 vol%). The XRD analysis shows that all the samples are pure perovskite oxides. An infrared study confirms that the compounds are pure excepted LaCoO{sub 3} calcined at 700 C (presence of La{sub 2}O{sub 3}). The specific surface areas are respectively: 32, 5, 7 and 8 m{sup 2}.g{sup -1} for the Co, Ni perovskites calcined at 800 C and for the Mn and Fe perovskites calcined at 700 C. According with the light-off temperatures T{sub 50}, the activity of the catalysts decreases as follows: LaMnO{sub 3} (226 C) {>=} LaCoO{sub 3} (248 C) {>=} LaNiO{sub 3} (274 C) {>=} LaFeO{sub 3} (282 C). All the catalysts are selective into CO{sub 2}. It has been shown that the calcination temperature has a role on the activity of the Co and Ni perovskites for the combustion of toluene. A decrease of the calcination temperature of 100 C (LaCo) and of 200 C (LaNi) increases the activity of LaCoO{sub 3} whereas the inverse effect is observed for LaNi. The influence of the kind of the transition metal in B site will be discussed from the physico-chemical characterizations. (O.M.)

  1. The toxicodynamics of benzene, ethanol, and benzene plus ethanol based on the histopathological examination of selected organs in the rat.

    Błoch, P; Kulig, A; Paradowski, M; Wybrzak-Wróbel, T

    1990-01-01

    The influence of ethanol on benzene toxicity in the course of prolonged 26-week intoxication was investigated in Wistar rats. A dose of 1/30 DL50/24h of benzene in oil solution was administered subcutaneously once daily, 5 days a week. Drinking water was replaced by a 10% water solution of ethanol ad libidum. Specimens of the liver, spleen, kidneys, lungs, and heart were taken for histopathological examination. Changes in the liver confirmed the hepatotoxic action of benzene and were unaffected by the simultaneous administration of ethanol. In the lungs and spleen the lymphatic system showed signs of damage which became more pronounced in joint exposure to benzene plus ethanol. The authors conclude that alcohol abuse by people professionally exposed to benzene and other lipophilic petroleum derivatives (as in the petrochemical industry) may increase the toxic effects of these substances. PMID:2132937

  2. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions (196Hg, 198Hg, 202Hg, 204Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope 204Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m3 for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m3 at 1 s averaging and 0.1 mg/m3 at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. - Highlights: • Portable benzene analyser is designed for direct benzene detection in air and gas. • Zeeman effect absorption spectrometry ensures very low benzene detection limits. • The Hg 2537 nm emission line from capillary mercury lamp is used for absorption. • The best sensitivity and selectivity is found using Hg 204 isotope light source. • Mercury influence is eliminated by using a sorption filter at the inlet

  3. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

    Revalde, Gita, E-mail: gitar@latnet.lv [Institute of Technical Physics, Riga Technical University, P.Valdena 3, Riga LV 1050 (Latvia); Sholupov, Sergey; Ganeev, Alexander; Pogarev, Sergey; Ryzhov, Vladimir [St. Petersburg State University, Universitetskaya nab., 7/9, St. Petersburg 199034 (Russian Federation); Skudra, Atis [Institute of Atomic Physics and Spectroscopy, University of Latvia, Skunu 4, Riga (Latvia)

    2015-08-05

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ({sup 196}Hg, {sup 198}Hg, {sup 202}Hg, {sup 204}Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope {sup 204}Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m{sup 3} for benzene) level, the interference from SO{sub 2}, NO{sub 2}, O{sub 3}, H{sub 2}S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m{sup 3} at 1 s averaging and 0.1 mg/m{sup 3} at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. - Highlights: • Portable benzene analyser is designed for direct benzene detection in air and gas. • Zeeman effect absorption spectrometry ensures very low benzene detection limits. • The Hg 2537 nm emission line from capillary mercury lamp is used for absorption. • The best sensitivity and selectivity is found using Hg 204 isotope light source. • Mercury influence is eliminated by using a sorption filter at the inlet.

  4. Biotransformation and Production from Hansenula Anomala to Natural Ethyl Phenylacetate

    Tian Xun

    2015-01-01

    Full Text Available Ethyl phenylacetate can be widely applied in many industries, such as food, medicines, cosmetics and medicinal herbs. At the moment, the production of natural ethyl phenylacetate is very limited. However, the biotransformation production of natural ethyl phenylacetate has an very extensive application prospect. This paper is written by taking the phenylacetic acid tolerance and the esterifying enzyme activity as the two indexes for screening the HA14 strain of hansenula anomala mutagenic which is regarded as the microorganism of ethyl phenylacetate production through biotransformation. By optimizing the production condition of phenylacetic acid and the esterification condition of ethyl phenylacetate, the production of ethyl phenylacetate accomplished through biotransformation within 72 hours can reach 864mg/L which is 171% of that of the initial bacterial strain.

  5. A pilot study on the stability of toluene in blood from workers

    Ogawa Masanori

    2012-12-01

    Full Text Available Abstract Background Biological monitoring is used to assess toluene exposure in medical examinations. The American Conference of Industrial Hygienists, Japanese Society for Occupational Health and Deutsche Forschungsgemeinschaft have proposed various biological exposure determinants, such as toluene in blood and urine, and o-cresol in urine. Toluene in blood is a common biomarker among them. Toluene is a volatile organic solvent; therefore, sample preservation under appropriate conditions before measurement is necessary. However, little study has been done on the stability of toluene in workers blood samples under conditions simulating those of a medical examination. Finding We carried out a pilot study on the stability of toluene in blood from humans, according to different methods of sample preservation. Toluene in blood was analyzed by head space-gas chromatography/mass spectrometry. The sealing performance of the vial was examined by using toluene-added blood and the stability of toluene in blood according to the preservation period was examined by using blood from toluene-handling workers, which was collected with vacuum blood tubes. The sealing performance of the headspace vial used in this study was good for three days and toluene in blood in tubes from workers was stable at least within 8 hours up to blood packing at 4C. Conclusion We could propose that the collected blood need only be transferred into headspace vials on the collection day and analyzed within a few days, if the samples are preserved at 4C. Our data size is limited; however, it may be considered basic information for biological monitoring in medical examinations.

  6. Ethyl 4-acetyl-5-oxo-3-phenylhexanoate

    Hongwei Wang

    2011-04-01

    Full Text Available The reaction of ethyl 3-bromo-3-phenylpropanoate with pentane-2,4-dione, in the presence of palladium(II acetate and triphenylphosphine, in dimethylformamide, unexpectedly gave the title product, C16H20O4. The molecule contains one chiral C atom but the crystal is racemic. In the crystal, neighboring molecules form a chain along [100] through three weak CH...O interactions. Furthermore, a double-stranded structure is formed through weak CH...O interactions between two parallel chains.

  7. Ethyl 2-[N-(2-Formylphenylbenzenesulfonamido]acetate

    2009-03-01

    Full Text Available In the title compound, C17H17NO5S, the N atom is sp3-hybridized and the S atom has a distorted tetrahedral configuration. The dihedral angle between the two aromatic rings is 30.0?(1, and that between the ethyl acetate group and the formylphenyl ring is 77.4?(1. The molecules are linked into chains along [100] by CH...O hydrogen bonds and the chains are linked via CH...? interactions.

  8. Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,

    Mathew Obichukwu EDOGA

    2006-01-01

    First, phenol - formaldehyde (PF) and urea - formaldehyde (UFII) resins were separately conventionally prepared in our laboratory. Also, UF resin synthesized from the acid modified synthesis procedure was synthesized in a purely acid medium of pH 1.0, FU molar ratio of 1.0 and at 50oC (one-stage acid modified-synthesis procedure). Subsequently, the UF resin II was modified during synthesis by incorporating ethylated urea-ether (EUER) (i.e. UFIII) and glycerol (GLYC) (i.e. UFV) cured with and ...

  9. 21 CFR 172.872 - Methyl ethyl cellulose.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl ethyl cellulose. 172.872 Section 172.872... CONSUMPTION Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose... a cellulose ether having the general formula [C6H(10 -x-y)O5(CH3)x(C2H5)y]n, where x is the...

  10. Study of the rearrangement of N-alkylaniline to p-aminoalkylbencene. I. N-ethyl-l-{sup 1}4C-aniline; Estudio de la transposicion de N-alquilanilinas A p-Aminoalquilbenceno mediante {sup 1}4C

    Molera, M. J.; Gamboa, J. M.; Val Cob, M. del

    1961-07-01

    The rearrangement of N-ethylaniline to p-aminoethylbenzene has been studied over the temperature range 200-300 degree centigrade using different catalysts: Cl{sub 2}Co, Cl{sub 2}Zn, Cl{sub 2}Ni, Cl{sub 3}Al, Cl{sub 2}Cd and Br H.N-ethyl-1-{sup 1}4C-aniline has been synthesized from ethyl-1-{sup 1}4C-iodide and aniline and its rearrangement to p-aminoethyl-benzene proves that the ethyl group does not rearrange itself during the reaction. A scheme for the degradation of both the N-ethyl-1-{sup 1}4C aniline and the p-aminoethylbenzene produces is described. (Author) 14 refs.

  11. Solubilities of benzene sulfonamide in supercritical CO2 in the absence and presence of cosolvent

    Highlights: ► Solubility of benzene sulfonamide in SCCO2 was measured with and without coslovent. ► The measured data were correlated by using 10 semi-empirical models. ► The thermodynamic properties (ΔH, ΔHsub. ΔHsolv.) of solid solute were obtained. ► The effects of pressure and temperature were explained by molecular interaction. ► The enhancement factor of each cosolvent was calculated. - Abstract: Solubilities of benzene sulfonamide in supercritical CO2 were measured by using dynamic method at temperature ranging from 308.15 to 328.15 K over a pressure range of 11.0–21.0 MPa. The experimental data in binary system were correlated with eight semi-empirical equations. The calculated result shows that the equation proposed by Adachi and Lu (A–L) provides the best correlation to the experimental data. The AARD (%) for A–L equation is 5.53. The thermodynamic properties (total enthalpy ΔH, sublimation enthalpy ΔHsub. and solvation enthalpy ΔHsolv.) of solid solute were obtained. The cosolvent investigated in this work was ethanol, ethylene glycol and ethyl acetate, respectively. The solubilities in ternary system were determined with molar fraction of 3.5% (cosolvent) at 308.15 K over a pressure range of 11.0–21.0 MPa. The enhancement factor of each cosolvent was calculated. The experimental data in ternary system were correlated by using T–G equation and modified Sovova equation.

  12. Testing for ethanol markers in hair: discrepancies after simultaneous quantification of ethyl glucuronide and fatty acid ethyl esters.

    Kintz, P; Nicholson, D

    2014-10-01

    The hair of 97 cases were analysed for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE, including ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) according to the Society of Hair Testing guidelines to examine the role of both tests in documenting chronic excessive alcohol drinking, particularly when the results are in contradiction. 27 (27.8%) results were EtG negative and FAEE positive, when applying the SoHT cut-offs, probably due to the use of alcohol-containing hair products. Four cases (4.1%) were EtG positive and FAEE negative that were attributed to the use of herbal lotions containing EtG. PMID:24794020

  13. Metabolism of Chlorotoluenes by Burkholderia sp. Strain PS12 and Toluene Dioxygenase of Pseudomonas putida F1: Evidence for Monooxygenation by Toluene and Chlorobenzene Dioxygenases

    Lehning, A.; Fock, U.; Wittich, R.; Timmis, K.N.; Pieper, D. H.

    1997-01-01

    The degradation of toluene by Pseudomonas putida F1 and of chlorobenzenes by Burkholderia sp. strain PS12 is initiated by incorporation of dioxygen into the aromatic nucleus to form cis-dihydrodihydroxybenzenes. Toluene-grown cells of P. putida F1 and 3-chlorobenzoate-grown cells of Burkholderia sp. strain PS12 were found to monooxygenate the side chain of 2- and 3-chlorotoluene to the corresponding chlorobenzyl alcohols. Further metabolism of these products was slow, and the corresponding ch...

  14. A determinao colorimtrica de vapres de benzeno no ar The colorimetric determination of benzene vapors in air

    Herbert M. A. Stettiner

    1970-06-01

    Full Text Available Estudou-se um mtodo simples para a determinao de pequenas quantidades de vapres de benzeno no ar, aplicvel em presena de seus homlogos. A interferncia dos homlogos eliminada destruindo seus nitrocompostos segundo BAERNSTEIN (1943 pela oxidao com cido crmico. ste procedimento combinado com o de DOLIN2,3 (1943, 1947 que isola o m-dinitrobenzeno pela extrao com ter etlico, usando o extrato etreo para a revelao da cr vermelha e para a colorimetria.A simple method is developed for the determination of small amounts of benzene vapor in air in the presence of its homologues. The chromic acid method of BAERNSTEIN (1943 for eliminating the interference of the homologues is combined with the procedure of DOLIN2,3 (1943, 1947 who makes the final colorimetric measurement after separating the colored matter by extraction with ethyl ether.

  15. Going the distance with ethyl alcohol

    If all had gone according to plan, ethyl alcohol would be in the driver's seat now, cruising down the highway and getting ready to speed into high gear. Instead, this renewable fuel, chemical reagent and solvent is navigating a complex obstacle course, watching warily for sharp turns and mixed signals. Globally, the supply and demand for all grades of ethyl alcohol is awry. Production of industrial-grade material is running at full throttle and prices are going up. Much of the upheaval over ethanol can be traced to the US Environmental Protection Agency and the renewable oxygenate standard (ROS) of the Clean Air Act. Under ROS, 15% of oxygenates used in gasoline sold this year was to be derived from a renewable source. Next month, that percentage was to have been doubled to 30%. Enticed by projections of upwards of 2 billion gal/yr of fermentation alcohol to comply with ROS, producers rushed to expand capacity. But to the producers' dismay, EPA was forced to backpedal on ROS. When representatives of the petroleum industry filed suit and won a stay, EPA rescinded its ROS regulation and ethanol producers were left in the lurch. High prices for corn is also putting the squeeze on inventories of industrial alcohol. Synthetic ethanol production, from ethylene for example, is booming, however. This paper discusses the ethanol market factors

  16. Detection of Toluene Degradation in Bacteria Isolated from Oil Contaminated Soils

    Toluene (C7H8) 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)

  17. Collision-induced Energy Transfer and Bond Dissociation in Toluene by H2/D2

    Energy transfer and bond dissociation of C-Hmethyl and C-Hring in excited toluene in the collision with H2 and D2 have been studied by use of classical trajectory procedures at 300 K. Energy lost by the vibrationally excited toluene to the ground-state H2/D2 is not large, but the amount increases with increasing vibrational excitation from 5000 and 40,000 cm.1. The principal energy transfer pathway is vibration to translation (V-T) in both systems. The vibration to vibration (V-V) step is important in toluene + D2, but plays a minor role in toluene + H2. When the incident molecule is also vibrationally excited, toluene loses energy to D2, whereas it gains energy from H2 instead. The overall extent of energy loss is greater in toluene + D2 than that in toluene + H2. The different efficiency of the energy transfer pathways in two collisions is mainly due to the near-resonant condition between D2 and C-H vibrations. Collision-induced dissociation of C-Hmethyl and C-Hring bonds occurs when highly excited toluene (55,000-70,400 cm-1) interacts with the ground-state H2/D2. Dissociation probabilities are low (10-5∼10-2) but increase exponentially with rising vibrational excitation. Intramolecular energy flow between the excited C-H bonds occurring on a subpicosecond timescale is responsible for the bond dissociation

  18. Behavioral Effects of Sub-Acute Inhalation of Toluene in Adult Rats

    Reports of behavioral effects of repeated inhalation of toluene in rats have Yielded inconsistent fmdings. A recent study from this laboratory (Beasley et al., 2010) observed that after 13 weeks of inhaled toluene ("sub-chronic" exposure scenario), rats showed mild but persiste...

  19. Abatement of toluene from gas streams via ferro-electric packed bed dielectric barrier discharge plasma

    Destruction of gaseous toluene via ferro-electric packed bed dielectric barrier discharge plasma in a coaxial cylindrical reactor was carried out at atmospheric pressure and room temperature. The difference among three kinds of reactors was compared in terms of specific energy density (SED), energy yield (EY), toluene decomposition. In order to optimize the geometry of the reactor, the removal efficiency of toluene was compared for various inner electrode diameters. In addition, qualitative analysis on by-products and particular discussion on toluene abatement mechanisms were also presented. It has been found that ferro-electric packed bed DBD reactor could effectively decompose toluene. Toluene removal efficiency enhanced with increasing SED. With respect to toluene conversion, 1.62 mm electrode appeared to be superior to 1.06 mm electrodes. BaTiO3 reactor had the highest toluene removal efficiency among the reactors. For NaNO2 reactor, the highest EY could reach 17.0 mg/kWh to a certain extent.

  20. 4-Nitro­anilinium p-toluene­sulfonate

    P. K. Sivakumar; Krishnakumar, M.; Kanagadurai, R.; G. Chakkaravarthi; Mohankumar, R.

    2012-01-01

    In the cation of the title salt, C6H7N2O2 +·C7H7O3S−, the benzene ring makes a dihedral angle of 10.2 (2)° with the nitro group. In the crystal, the cations and anions are linked by weak N—H⋯O hydrogen bonds, forming a layer parallel to the ac plane. A weak C—H⋯O inter­action and π–π inter­actions [centroid–centroid distances of 3.738 (3) and 3.748 (3) Å] also observed within the layer.

  1. Thermodynamic and chemical behavior of benzene under shock conditions

    Maillet, Jean-Bernard; Pineau, Nicolas; Bourasseau, Emeric

    2007-06-01

    The thermodynamic and chemical behavior of benzene along its hugoniot curve is investigated using Molecular Dynamics simulations with reactive potentials. The simulated hugoniot curve is in good agreement with experimental data at low pressures. Moreover, the decomposition threshold is well reproduced. In the high pressure regime, reactive simulations show that benzene rapidly decomposes, but resulting pressures do not match experimental ones anymore. Simulations starting with diamond nanoparticules and hydrogen gas give good pressures along the hugoniot. These simulations seem to confirm the existence of carbon clusters with diamond structure in the decomposition products of benzene.

  2. Distribution of Fe59 in benzene and iomex treated rats

    The distribution of Fe59 in plasma and blood at various time intervals has been studied in control, benzene and iomex administered, and anemic rats. A significant difference between control and benzene, and iomex treated animals was observed in the rate of reappearance of Fe59 in blood circulation. The accumulation of Fe59 in various organs was noted at the end of 48 h. A significant increase in the radio-iron content was observed in bone marrow, spleen and liver of benzene and iomex treated rats as compared to those of control rats. (orig.)

  3. Effects of Toluene on Microbially-Mediated Processes Involved in the Soil Nitrogen Cycle

    Fuller; Scow

    1996-07-01

    The effects of toluene on indigenous microbial populations involved in the soil nitrogen cycle were examined. Ammonia oxidation potential (AOP) and nitrite oxidation potential (NOP) were both reduced after incubation with high toluene concentrations for 45 days, with the former activity showing greater sensitivity. KCl-extractable ammonium (NH4+ext) levels increased dramatically in soil exposed to high toluene levels, and arginine ammonification was not significantly affected. Alfalfa-amended soil incubated in the presence of 200 &mgr;g toluene ml-1 showed progressive accumulation of NH4+ext over 37 days, indicating that mineralization of plant-associated nitrogen was not hindered by toluene. AOP in treated soil was much less than in control soil on days 7 and 37, but the MPN of ammonia oxidizers in control and exposed soil were not significantly different. Soil incubated with 100 &mgr;g toluene ml-1for 28 days, vented and allowed to incubate for an additional 7 to 30 days, exhibited only slight increases in AOP and NOP, while NH4+ext returned to control levels within a week. Soil exposed to 200 &mgr;g toluene ml-1 and treated in the same manner showed no increases in either AOP or NOP, and NH4+extremained elevated for the duration of the experiment, indicating more long-term effects on soil nitrogen cycling had occurred. Ammonia oxidizer levels in control soil and soil incubated with 100 &mgr;g toluene ml-1 were not appreciably different, whereas levels of ammonia oxidizers were very low in soil exposed to 200 &mgr;g toluene ml-1 and increased only slightly by 30 days post vent. Experiments to determine how toluene affects the AOP of soil indicated a competitive inhibition mechanism, with an effective concentration causing 50% reduction in activity (EC50) of 11 &mgr;M toluene, and a competitive inhibition constant (Ki) of 0.1 0.05 &mgr;M toluene. These results indicate the potential for toluene to adversely impact nitrogen cycling in the terrestrial ecosystem by affecting indigenous soil nitrifiers, which are sensitive to lower levels of toluene than has been previously reported. PMID:8688007

  4. Toluene impurity effects on CO2 separation using a hollow fiber membrane for natural gas

    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.

  5. Multiple photon excitation of adsorbed toluene by KrF laser

    Varakin, V. N.

    2016-01-01

    KrF laser-induced multiple photon dissociation and desorption of toluene condensed on fused silica have been studied using mass spectrometry. The three-photon (2-1) excitation of the molecule including its transition connected with laser stimulated emission was found to control this dissociation in all coverages as well as the ejection of single toluene molecules from the multilayer. Fragments were also produced in two successive steps of two-photon excitation that caused the release of toluene clusters from the adsorbed multilayer and the breaking of intramolecular bonds in the desorbed species. A mechanism of toluene and its cluster ejection has been proposed. The difference in the dynamics of the excited adsorbed and gaseous molecules has been discovered. The irradiation of the silica surface by KrF laser was found to lead to an increase of the local laser field acting on the adsorbed toluene of more than 50 times.

  6. Developmental toxicity of toluene in male rats: effects on semen quality, testis morphology, and apoptotic neurodegeneration

    Dalgaard, M.; Hossaini, A.; Hougaard, K.S.; Hass, Ulla; Ladefoged, Ole

    2001-01-01

    In one study, pregnant Wistar rats were exposed to 1200 ppm toluene by inhalation 6 h a day from gestational day (GD) 7 to postnatal day (PND) 18. Sperm analysis was performed in the adult male offspring at PND 110 bp using computer-assisted sperm analysis. Toluene if id not affect the semen qual...... postnatal migration of granule cells to their final destination, or by toluene-induced retardation of generalised fetal growth....... pre- and postnatal exposure to 1200 ppm toluene nor prenatal exposure to 1800 ppm induced significant effects on the reproductive parameters investigated. However, prenatal exposure to 1800 ppm toluene did increase neuronal apoptosis in the cerebellum of weaned male rats, possibly by delaying...

  7. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    G. Sarwar

    2010-12-01

    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 mixing ratios. While the new mechanism increases predicted ozone, it does not enhance ozone production efficiency. Sensitivity study suggests that it can further enhance ozone if elevated toluene emissions are present. While changes in total fine particulate mass are small, predictions of in-cloud SOA increase substantially.

  8. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    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.

  9. Ethyl 4-(tert-butylamino-3-nitrobenzoate

    Aisyah Saad Abdul Rahim

    2008-08-01

    Full Text Available In the title compound, C13H18N2O4, intramolecular N—H...O, N—H...N and C—H...O (× 3 hydrogen bonds generate S(6 and S(5 ring motifs. There are two crystallographically independent molecules (A and B in the asymmetric unit. The nitro group is coplanar with the benzene ring, with O—N—C—C torsion angles of −0.33 (13 and 0.93 (14° in molecules A and B, respectively. In the crystal structure, neighbouring molecules are linked together by intermolecular C—H...O hydrogen bonds. In addition, the crystal structure is stabilized by π–π interactions with centroid–centroid distances ranging from 3.7853 (6 to 3.8625 (6 Å.

  10. Time Domain Reflectometric and spectroscopic studies on toluene + butyronitrile solution

    Karthick, N. K.; Arivazhagan, G.; Kumbharkhane, A. C.; Joshi, Y. S.; Kannan, P. P.

    2016-03-01

    The dielectric parameters of toluene + butyronitrile solution have been obtained by time domain reflectometry (TDR) technique in the frequency range from 10 MHz to 30 GHz at 298 K. Spectroscopic (FTIR and 13C NMR) studies have also been carried out on the solution and the results of the studies show that neat butyronitrile is self-associative through C-H⋯N contacts and weak intermolecular forces of C-H⋯N and C-H⋯π type are operative in the solution. The obtained dielectric parameters such as Kirkwood correlation factor g, relaxation time τ etc. have been analyzed in view of these weak intermolecular forces. The weak non-covalent interactions between heteromolecules appear to have no influence on the ideality of ɛm vs X2 curve of the solution. Heteromolecular entities with weak intermolecular forces experience larger hindrance leading to longer relaxation time τ.

  11. Gas phase toluene isopropylation over high silica mordenite

    Sreedevi Upadhyayula

    2010-07-01

    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 like temperature, time-on-stream, weight hourly space velocity (WHSV), reactant mole ratio on this catalyst activity are discussed. The cymene selectivity was found to increase with reaction temperature and passed through a maximum at 473 K. The deactivation with time-onstream is almost negligible. Lower isopropyl alcohol concentration in the feed improved cymene selectivity. The conversion and selectivity to cymenes were compared with those of the large pore beta catalyst. The rate constant and activation energy were found to be 7.34 m3/kg h and 41.84 kJ/mol, respectively using homogeneous kinetic model.

  12. Viscometric study of high-cis polybutadiene in toluene solution

    Viscometric measurements, in toluene solution at 30 deg C, 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. (author)

  13. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How does a refiner apply for a benzene... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading (abt) Program § 80.1285 How does a refiner apply for a benzene baseline? (a) A benzene...

  14. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    2010-07-01

    ... requirements for gasoline benzene compliance? 80.1356 Section 80.1356 Protection of Environment ENVIRONMENTAL... Benzene Attest Engagements § 80.1356 What are the attest engagement requirements for gasoline benzene... that contain gasoline benzene and gasoline volume information. (2) Agree the yearly volumes of...

  15. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    2010-07-01

    ... the gasoline benzene program? 80.1220 Section 80.1220 Protection of Environment ENVIRONMENTAL... Benzene General Information § 80.1220 What are the implementation dates for the gasoline benzene program? (a) Benzene standard. (1) For the annual averaging period beginning January 1, 2011, and for...

  16. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  17. Exposure to benzene metabolites causes oxidative damage in Saccharomyces cerevisiae.

    Raj, Abhishek; Nachiappan, Vasanthi

    2016-06-01

    Hydroquinone (HQ) and benzoquinone (BQ) are known benzene metabolites that form reactive intermediates such as reactive oxygen species (ROS). This study attempts to understand the effect of benzene metabolites (HQ and BQ) on the antioxidant status, cell morphology, ROS levels and lipid alterations in the yeast Saccharomyces cerevisiae. There was a reduction in the growth pattern of wild-type cells exposed to HQ/BQ. Exposure of yeast cells to benzene metabolites increased the activity of the anti-oxidant enzymes catalase, superoxide dismutase and glutathione peroxidase but lead to a decrease in ascorbic acid and reduced glutathione. Increased triglyceride level and decreased phospholipid levels were observed with exposure to HQ and BQ. These results suggest that the enzymatic antioxidants were increased and are involved in the protection against macromolecular damage during oxidative stress; presumptively, these enzymes are essential for scavenging the pro-oxidant effects of benzene metabolites. PMID:27016252

  18. Variability of benzene exposure among filling station attendants

    A monitoring survey of filling station attendants aimed at identifying sources of variability of exposure to benzene and other aromatics was carried out. Concurrent samples of the worker's breathing zone air, atmospheric air in the service station proximity, and gasoline were collected, along with information about daily workloads and other exposure-related factors. Benzene personal exposure was characterised by a small between-worker variability and a predominant within-worker variance component. Such elevated day-to-day variability yields to imprecise estimates of mean personal exposure. Almost 70% of the overall personal exposure variance was explained by a model including daily benzene from dispensed fuel, presence of a shelter over the refueling area, amount of fuel supplied to the station if a delivery occurred, and background atmospheric benzene concentration

  19. Reactions of energetic carbon-11 with benzene leading to acetylene

    The reactions of energetic carbon-11 leading to acetylene were studied in specifically deuteriated benzene and 50/50 mixtures of perdeuteriated and perprotonated benzenes and alkanes. The contributions of intermolecular and intramolecular mechanisms in acetylene formation in benzene were deduced from the relative yields of the three isotopic acetylenes /sup (11)/C2H2, /sup (11)/C2HD, and /sup (11)/C2D2. High-energy stripping and abstraction reactions of /sup (11)/C2 and /sup (11)/C2H ions appear to account for acetylene formed via an intermolecular pathway. After correction for the intermolecular mechanisms, the remaining acetylene is formed mainly by direct insertion (? or ?) plus a small contribution from a mechanism involving random selection of H or D in the benzene molecule

  20. Environment-dependent desorption of benzene molecules

    Meserole, Chad A.; Vandeweert, Erno; Dou, Yusheng; Postawa, Zbigniew; Winograd, Nick

    2001-08-01

    We have investigated the dependence of the 8 keV Ar+ ion beam-induced desorption of neutral benzene (C6H6) molecules on the local environment. The probed system was comprised of carefully constructed combinations of C6H6 and sec-Butyl Alcohol (sBA) deposited on Ag(111). A pulsed 8 keV Ar+ ion beam at 45 incidence was used to stimulate the desorption of adsorbed molecules. Using state-selective resonant ionization spectroscopy and time-of-flight (TOF) mass spectrometry, C6H6 molecules in the ground state and in the first level of a vibrationally excited state were probed. TOF distributions were measured versus the exposure of the sBA. The results show that the ejection of the C6H6 depends strongly on both the internal energy and thickness of the formed layer. In general, as more sBA is added to the probed system, the TOF distributions tend to broaden and shift to higher times, and the relative C6H6 yields diminish rapidly. The vibrationally excited C6H6 is more sensitive to the addition of sBA, and an interpretation of the combined data suggests that the C6H6 desorbed in an excited state originates from the organic/vacuum interface.

  1. Positronium quenching in liquid and solid octanol and benzene

    Shantarovich, V.P.; Mogensen, O.E.; Goldanskii, V.I.

    1970-01-01

    The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase.......The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase....

  2. Nitrophenols Reduction in the Benzene Adiabatic Nitration Process

    Quadros, Paulo A.; Castro, José A. A. M. Castro; Baptista, Cristina M. S. G.

    2004-01-01

    The benzene adiabatic nitration process has been carried out in a pilot plant to enable the study of this reaction under relevant industrial operating conditions, aiming to increase the reaction conversion and selectivity by reducing the nitrophenols. The influence of relevant operating parameters such as the reaction temperature, benzene-to-nitric acid molar feed ratio (FB/FN), and stirring speed was studied. The operation ranges covered were as follows: reaction temperature, ...

  3. 2,6-Bis(9-ethyl-9H-carbazolylmethylenecyclohexanone

    Abdullah M. Asiri

    2009-10-01

    Full Text Available The title compound, 2,6-bis(ethyl-9-ethyl-9H-carbazolylmethylenecyclohexanone has been synthesized by condensation of 9-ethylcarbazole-3-aldehyde and cyclohexanone in ethanol in the presence of pyridine. The structure of this new compound was confirmed by elemental analysis, IR, 1H NMR, 13C NMR and EI-MS spectral analysis.

  4. Evaluation of headspace-gas chromatography/mass spectrometry for the analysis of benzene in vitamin C drinks; pitfalls of headspace in benzene detection.

    Ju, Hyun Kyoung; Park, Jeong Hill; Kwon, Sung Won

    2008-08-01

    Recently, there have been reports regarding the presence of benzene in vitamin C drinks. This is caused by sodium benzoate and ascorbic acid (vitamin C), which can react together to induce benzene formation. While the headspace gas chromatography method is well known for the detection of benzene, there could be pitfalls in the process of benzene extraction. This study was performed to check if benzene could be generated under high-temperature incubation conditions. As a result, the amount of benzene detected by headspace-gas chromatography/mass spectrometry (HSGC/MS) was affected by temperature changes. As the temperature of the sample vial was increased, newly generated benzene from the headspace also increased, causing false-positive determination of benzene. Although 80 degrees C is generally accepted for the temperature of headspace sample vials, lower temperatures, such as 40 degrees C, minimize the false-positive identification of benzene. Considering that this minimization allows benzene to be quantified at around 5 ppb, this lower temperature should definitely be considered since benzene, which is formed in sodium benzoate, can appear in vitamin C drinks under certain circumstances. The proposed analysis method of benzene in vitamin C drinks by HSGC/MS at 40 degrees C is an accurate and universal method for the monitoring of benzene without false-positive identification. PMID:18506678

  5. Microbial degradation of toluene under sulfate-reducing conditions and the influence of iron on the process

    Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (Md.). Similar results were obtained for enrichment cultures in which toluene was the sole carbon source. Several lines of evidence suggest that toluene degradation was directly coupled to sulfate reduction in Patuxent River microcosms and enrichment cultures: (1) the two processes were synchronous and highly correlated, (2) the observed stoichiometric ratios of moles of sulfate consumed per mole of toluene consumed were consistent with the theoretical ratio for the oxidation of toluene to CO2 coupled with the reduction of sulfate to hydrogen sulfide, and (3) toluene degradation ceased when sulfate was depleted, and conversely, sulfate reduction ceased when toluene was depleted. Mineralization of toluene was confirmed in experiments with [ring-U-14C]toluene. The addition of millimolar concentrations of amorphous Fe(OH)3 to Patuxent River microcosms and enrichment cultures either greatly facilitated the onset of toluene degradation or accelerated the rate once degradation had begun. In iron-amended microcosms and enrichment cultures, ferric iron reduction proceeded concurrently with toluene degradation and sulfate reduction. Stoichiometric data and other observations indicate that ferric iron reduction was not directly coupled to toluene oxidation but was a secondary, presumably abiotic, reaction between ferric iron and biogenic hydrogen sulfide

  6. Occupational Risk Assessment of Benzene in Rubber Tire Manufacturing Workers

    SEYEDYOUNES HOSSEINI

    2014-12-01

    Full Text Available Tire manufacturing industry has a history of more than half a century in Iran, where 14 thousand workers are employed. The old and semi-automated processes equipment, backward technology, and raw materials impurity lead to significant exposures to occupational carcinogens such as benzene. This study was to assessment of benzene exposures and evaluation the resulting cancer risk in two tire-manufacturing factories. One hundred workers in  two  target  tire-manufacturing factories  selected  as  ―exposed  group‖.  Personal  monitoring was conducted in all process units according to NIOSH 1501 method. Inhalation health risk of benzene exposure was estimated via two assessment models. Data were analyzed using SPSS and quantitative values were reported as Mean ± Standard Error. Occupational exposure to benzene in 68 percent of workers has exceeded the current exposure limit. The highest level of benzene (5.06 ppm found in cement making unit. The odds ratio of leukemia was 2.06 times the working population without benzene exposure, as well; the cancer incidence was 16.14 cases per 1000 workers. This study as screening approach is first on addressing the risk assessment of Iranian tire manufacturing workers. The levels of personal exposures and cancer risk were unacceptable and this may provide a basis for developing the control measures in future.

  7. Kinetics and Mechanism of Pyridinolyses of Ethyl Methyl and Ethyl Propyl Chlorothiophosphates in Acetonitrile

    The kinetic studies on the reactions of ethyl methyl (2) and ethyl propyl (4) chlorothiophosphates with X-pyridines have been carried out in acetonitrile at 35.0 .deg. C. The free energy correlations with X show biphasic concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of ?X = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of ?X = 0.43(2) and 0.36(4) with weakly basic pyridines are interpreted as a change of the attacking direction of the X-pyridines from a frontside to a backside attack toward the chloride leaving group

  8. Surface-initiated ATRP of 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate on Phynox

    Phynox is of high interest for technological applications due to its high corrosion resistance, mechanical properties and biocompatibility. In combination with these remarkable characteristics, some Phynox applications require specific surface properties that can be imparted with suitable surface functionalizations of the oxide layer. The present work aims at studying the surface-initiated atom transfer radical polymerization (ATRP) of 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC) on Phynox substrates, using grafted 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid as initiator. The ability of the initiator to bind Phynox substrates and act as an initiator for ATRP of MPC is investigated. It appears that ATRP polymerization of MPC on modified Phynox substrates already takes place in aqueous media at room temperature, but the yield at 90 deg. C is superior.

  9. A Concise Review of Chromatographic Methods for the Analysis of Benzene and its Metabolites

    Khan, Haseeb Ahmad

    2006-01-01

    Benzene is an important pollutant with carcinogenic potential. The main sources of benzene exposure include its unabated industrial use, gasoline vapors, emissions from engines and tobacco smoke. Environmental and occupational exposure of benzene has been associated with serious health hazards. Analysis of benzene is therefore important for the monitoring of environmental quality. The metabolites of benzene, especially S-phenyl mercapturic acid (S-PMA) and trans, trans-muconic acid (t,t-MA...

  10. Environmental and biological monitoring of benzene during self-service automobile refueling.

    Egeghy, P P; Tornero-Velez, R.; Rappaport, S M

    2000-01-01

    Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (...

  11. Analysis of residual toluene in food packaging via headspace extraction method using gas chromatography

    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)

  12. Occupational exposure to toluene: neurotoxic effects with special emphasis on drinking habits.

    Antti-Poika, M; Juntunen, J; Matikainen, E; Suoranta, H; Hnninen, H; Sepplinen, A M; Liira, J

    1985-01-01

    Neurotoxic effects of toluene were examined in 43 male rotogravure printers exposed to toluene (age 27-63, mean 41 years; duration of exposure 11-40, mean 22 years) and 31 male offset printers of the same age with slight exposure to aliphatic hydrocarbons. A neurological examination, tests for autonomic nervous function, electroencephalography, psychological tests and computerized tomography of the brain were carried out in addition to a standardized interview. Exposure levels were evaluated for each person separately on the basis of his work history and the results of an earlier study on exposure levels at the same printing shops. Besides a thorough history of alcohol consumption, information about the printers' drinking habits was obtained from the occupational health care centers of the printing shops. The examinations found only slight abnormalities, and there were no statistically significant group differences in the prevalences of abnormalities. No correlations between the abnormalities and the exposure indices were found either. One of the retired workers, however, who had been exposed to high toluene concentrations for over 40 years, had been diagnosed as having chronic organic solvent intoxication. Heavy drinkers of alcohol were clearly more common in the toluene-exposed group. This study detected no clinically significant abnormalities attributable to toluene alone among workers exposed to 68-185 ppm (mean 117) of toluene for over 10 years. The connection between alcohol consumption and toluene exposure is interesting and deserves further study. PMID:4030116

  13. Biodegradation of toluene vapor in coir based upflow packed bed reactor by Trichoderma asperellum isolate.

    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. PMID:25903193

  14. Liver function in patients exposed to a toluene in a hydrocarbon processing plant

    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

  15. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    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-induced reward enhancement.

  16. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    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-induced reward enhancement.

  17. Diffusion of gold nanoparticles in toluene and water as seen by dynamic light scattering

    Although the range of applications for gold nanoparticles (Au NPs) is growing rapidly, the study of the diffusion in different solvents is rare. This paper describes the translational diffusion coefficient of Au NPs inside toluene and water measured by dynamic light scattering. The size of the nanoparticles is examined by transmission electron microscopy and compared with the hydrodynamic radius. The diffusion of the nanoparticles is measured in different angles and temperatures in the two solvents. It is shown that the diffusion measured in both systems obeys Arrhenius relation with the temperature. Although the viscosity of toluene is higher than that of water, the Au NPs are found to diffuse faster in toluene

  18. Effect of various solvents on the viscosity-average molecular weight of poly (vinyl acetate)

    Solution polymerization of Vinyl Acetate was carried out in various solvents (benzene, toluene, ethyl acetate, acetonitrile). Dilute solution viscometry was used to determine the viscosity-average molecular weight of the resulting Poly (Vinyl Acetate) (PV Ac) in each case. The viscosity-average molecular weight (M,J of PVAc was found to increase in the order benzene < toluene < ethyl acetate < acetonitrile, It was concluded that under the same reaction conditions (polymerization time, initiator quantity, solvent/monomer ratio, temperature), acetonitrile served as the best solvent for solution. polymerization of Vinyl Acetate monomer. (author)

  19. Biodegradation of pyrazosulfuron-ethyl by Acinetobacter sp. CW17.

    Wang, Yanhui; Du, Liangwei; Chen, Yingxi; Liu, Xiaoliang; Zhou, Xiaomao; Tan, Huihua; Bai, Lianyang; Zeng, Dongqiang

    2012-03-01

    The pyrazosulfuron-ethyl-degrading bacterium, designated as CW17, was isolated from contaminated soil near the warehouse of the factory producing pyrazosulfuron-ethyl in Changsha city, China. The strain CW17 was identified as Acinetobacter sp. based on analyses of 94 carbon source utilization or chemical sensitivity in Biolog microplates, conventional phenotypic characteristics, and 16S rRNA gene sequencing. When pyrazosulfuron-ethyl was provided as the sole carbon source, the effects of pyrazosulfuron-ethyl concentration, pH, and temperature on biodegradation were examined. The degradation rates of pyrazosulfuron-ethyl at initial concentrations of 5.0, 20.0, and 50.0 mg/L were 48.0%, 77.0%, and 32.6%, respectively, after inoculation for 7 days. The growth of the strain was inhibited at low pH buffers. The chemical degradation occurs much faster at low pH than at neutral and basic pH conditions. The degradation rate of pyrazosulfuron-ethyl at 30°C was faster than those at 20 and 37°C by CW17 strains. Two metabolites of degradation were analyzed by liquid chromatography-mass spectroscopy (LC/MS). Based on the identified products, strain CW17 seemed to be able to degrade pyrazosulfuron-ethyl by cleavage of the sulfonylurea bridge. PMID:22388979

  20. Perspectives for the biotechnological production of ethyl acetate by yeasts.

    Lser, Christian; Urit, Thanet; Bley, Thomas

    2014-06-01

    Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester. PMID:24788328