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Sample records for toluene ethyl benzene

  1. Formation of ethyl benzene and styrene by side chain methylation of toluene using different zeolite catalysts

    OpenAIRE

    Abdallah, Mohamed Hassen Ahmed

    2011-01-01

    The principle aim of this work was to obtain good selectivities of styrene and ethyl benzene by alkylation of toluene with methanol in a single step. In order to achieve this side chain alkylation different alkali metal on HZSM-5, Y and BEA zeolites catalyst were prepared. Different molar ratio of toluene: methanol (5:1), (3:1), (1:1), (1:3) and (1:5) molar ratios have been applied. It found that 1:1 most suitable molar ratio for side chain alkylation of toluene. The mixture was pumped into t...

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

    International Nuclear Information System (INIS)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-12-15

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

  4. Atmospheric benzene and toluene

    International Nuclear Information System (INIS)

    Atmospheric concentrations of benzene (C6H6) and toluene (C7H8)have been observed at nine remote locations of the world ranging in latitude from inside the arctic circle to the south pole. The observations span all seasons at each location. In the northern hemisphere it is observed that C6H6 and C7H8 are most abundant during winter and least abundant during summer. Based on the limited data available, such cycles are not observed in the tropics. These findings are consistent with the expected latitudinal and seasonal variations of OH radicals which cause benzene and toluene to be removed from the atmosphere. The latitude distribution shows high concentrations at mid latitude and low levels in the southern hemisphere. This finding is consistent with the present understanding that the sources of benzene and toluene are primarily anthropogenic. The observed concentration distribution and varibility are consistent with the short expected atmospheric lifetime of the order of months for benzene and days for toluene

  5. Synthesis and characterization of composite polymer, polyethylene glycol grafted flower-like cupric nano oxide for solid phase microextraction of ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair and water samples.

    Science.gov (United States)

    Sarafraz-Yazdi, Ali; Zendegi-Shiraz, Amene; Es'haghi, Zarrin; Hassanzadeh-Khayyat, Mohammad

    2015-10-30

    In this research, poly (ethylene glycol)-poly (ethylene glycol) grafted flower-like cupric oxidenano particles (PEG-PEG-g-CuO NPs) as a novel fiber coating of solid-phase microextraction (SPME) were synthesized by using sol-gel technology. This fiber was successfully applied to extract and determine the ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair using head space-solid-phase microextraction (HS-SPME) coupled to gas chromatography-flame ionization detector. Characterization and chemical composition of the nano particle was performed by Fourier transform infrared spectroscopy (FT-IR), energy dispersion spectroscopy (EDS) and back scatter analysis (BSA). These methods confirmed the successful fabrication of PEG-g-CuO NPs. The surface morphology of the fibers were inspected by scanning electron microscopy. The scanning electron microscopy (SEM) revealed many "crack-like" features and highly porous structure on the surface of fiber. The synthesized nanocomposites were used for preconcentration and extraction of benzene, toluene, ethyl benzene and o-xylene (BTEX). The effects of operating parameters such as: desorption temperature and time, extraction temperature, extraction time, stirring speed and salt effect were investigated and optimized. Under the optimal conditions, the method detection limits and the limits of quantification were between 0.00025-50.00000pgmL(-1) and 0.00200-200.00000pgmL(-1), respectively. Linearity was observed over a range 0.00200-200000.00000pgmL(-1). The relative standard deviations for one fiber (repeatability; n=5) were obtained from 3.30 up to 5.01% and between fibers or batch to batch (n=3; reproducibility) in the range of 3.63-6.21%. The developed method was successfully applied to simultaneous determination of BTEX in human hairs, tap water and distillate water. PMID:26411479

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

    Scientific Electronic Library Online (English)

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

    2014-11-01

    Full Text Available L-Fenilalanina reage com zeólita Y submetida a uma troca iônica com níquel(II) para formar diaquabis(L-fenilalaninato)níquel(II), o qual é encapsulado nos poros da zeólita. Nesta forma encapsulada, o complexo de níquel funciona como um catalisador eficiente quando ciclo-hexeno, tolueno e etilbenzeno [...] são oxidados por peróxido de hidrogênio na presença de bicarbonato de sódio como cocatalisador. O catalisador foi facilmente recuperado da mistura de reação e foi reutilizado por três vezes sem perda observável de atividade. O catalisador heterogêneo apresentou atividade e seletividade significativamente mais altas quando comparado com o complexo diaquabis(L-fenilalaninato)níquel(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.

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

    DEFF Research Database (Denmark)

    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...

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

    International Nuclear Information System (INIS)

    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. In vitro metabolism of benzene, toluene, and xylene in rat liver

    International Nuclear Information System (INIS)

    A headspace gas chromatographic method was used to study the metabolism of benzene, toluene, and m-xylene in rat liver. Metabolism of benzene was lower than that of toluene, or m-xylene. Investigating metabolic rates of subcellular fractions, it was found that glutathione and glutathione S-transferase in the cytosol are involved in metabolism of benzene and toluene by microsomes. When both benzene and toluene are present in the incubation medium, they act as inhibitors of each others metabolism. Toluene and m-xylene metabolism were induced by the pretreatment of rats with phenobarbital (75 mg/kg), or 3-methylcholanthrene (25 mg/kg), or Aroclor 1254 (75 mg/kg) for 3 days, whereas benzene metabolism was not induced by all pretreatments. Another series of experiments was conducted to compare the effects of benzene, toluene, and xylene pretreatment on liver metabolism. In vivo metabolism of 14C-toluene and possible covalent binding of 14C-toluene to microsomes were also investigated. 14C-toluene when incubated with liver microsomes in the presence of a NADPH generating system formed benzylalcohol and cresols. Some of the radioactivity was covalently bound preferentially to microsomal proteins. The binding process required cytochrome P-450 dependent mixed function oxidases. This study suggests that toluene is metabolized to several reactive intermediates by liver microsomal enzymes and these metabolites are responsible for the covalent binding to macromolecules which represents a subcellular mechanism by which toluene may express its own in vivo toxicity

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

    Science.gov (United States)

    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.

  11. Benzene/toluene/p-xylene degradation. Part I. Solvent selection and toluene degradation in a two-phase partitioning bioreactor.

    Science.gov (United States)

    Collins, L D; Daugulis, A J

    1999-09-01

    A two-phase organic/aqueous reactor configuration was developed for use in the biodegradation of benzene, toluene and p-xylene, and tested with toluene. An immiscible organic phase was systematically selected on the basis of predicted and experimentally determined properties, such as high boiling points, low solubilities in the aqueous phase, good phase stability, biocompatibility, and good predicted partition coefficients for benzene, toluene and p-xylene. An industrial grade of oleyl alcohol was ultimately selected for use in the two-phase partitioning bioreactor. In order to examine the behavior of the system, a single-component fermentation of toluene was conducted with Pseudomonas sp. ATCC 55595. A 0.5-1 sample of Adol 85 NF was loaded with 10.4 g toluene, which partitioned into the cell containing 1 l aqueous medium at a concentration of approximately 50 mg/l. In consuming the toluene to completion, the organisms were able to achieve a volumetric degradation rate of 0.115 g l-1 h-1. This system is self-regulating with respect to toluene delivery to the aqueous phase, and requires only feedback control of temperature and pH. PMID:10531648

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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 (3?m?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

  14. Hematological indices of peripheral blood in workers occupationally exposed to benzene, toluene and xylene.

    Science.gov (United States)

    Moszczy?ski, P; Lisiewicz, J

    1983-12-01

    In 106 workers occupationally exposed to benzen, toluen and xylene through 1 to 122 months basic hematological indices of peripheral blood were evaluated. The benzene, toluene and xylene concentrations in the air at workplaces were equal to 0-370, 0-580 and 0-506 mg/m3, respectively. The workers were subdivided into three subgroups according to the service time corresponding to 1-29, 31-54 and 55-122 months. The first hematological changes noted in the workers studied consisted of diminishing the mean corpuscular hemoglobin and the mean corpuscular hemoglobin concentration in erythrocytes. Increased numbers of reticulocytes, lowered total count of leukocytes due to decreased numbers of T and "non-T, non-B" cells as well as increased numbers of monocytes were other signs of exposure investigated. Increased numbers of reticulocytes were noted in all workers independently of service time whereas other hematological alterations presented above were marked only in the subgroup of workers exposed to benzene, toluene and xylene through 55 to 122 months. It was stated that the T cell count decreased gradually in relationship with an extent of exposure time (negative correlation). Since laboratory examinations serving the evaluation of health state of workers exposed are only few it was postulated that the E rosette test may be of practical use for monitoring the toxic effect of benzene, toluene and xylene on the lymphocyte system. PMID:6670413

  15. Dynamics of Ethyl Benzene Synthesis Using Aspen Dynamics

    Directory of Open Access Journals (Sweden)

    A. Sarath Babu, Babasheb Londhe

    2014-07-01

    Full Text Available The objective of the study is to generate a plant wide control strategy using Aspen Dynamics for synthesis of Ethyl Benzene process which consists of two CSTRs in series followed by two distillation columns. Steady state simulation has been carried out prior to dynamic simulation using Aspen Plus and exported to Aspen dynamics after providing the required sizing details under flow driven mode. In addition to default controllers, five more controllers are added and the necessary specifications regarding process variable, output variable and set point are specified for each controller. One cascade controller, two ratio controllers, two pressure controllers, four temperature controllers and six level controllers are used in the present study. Controllers are tuned by using Tyreus-Luyben and Ziegler-Nichols controller settings. The response of the whole process is studied for various step disturbances to find the optimal controller parameters and control structure.

  16. Kinetics of the reactions of hydroxyl radical with benzene and toluene

    International Nuclear Information System (INIS)

    Absolute rate constants for the reactions of the hydroxyl radical with benzene and toluene were measured within the temperature and pressure ranges 213 less than or equal to T less than or equal to 1150 K and 20 less than or equal to P less than or equal to 200 torr by using He, Ar, and SF6 as diluent gases. To help elucidate the variations in reaction mechanism with temperature, we also studied OH reactions with deuterated benzene (C6D6) and with selectively deuterated toluenes (C6H5CD3, C6D5CD3, and C6D5CH3). Three major reaction channels were characterized kinetically. At T less than or equal to 298 K, electrophilic addition of the OH radical to the aromatic ring is the dominant reactive pathway in all systems studied. At temperatures above 500 K, rapid decomposition of the thermalized adduct back to reactants diminishes the importance of the addition channel and leads to bimolecular reaction rate-constant values significantly lower than those measured near room temperature. At elevated temperatures, the ring hydrogen abstraction (for benzene) and side-chain hydrogen abstraction (for toluene) pathways are shown to be predominant. The measured bimolecular rate constants increase monotonically with increases in temperature above 500 K, and kinetic separation of the two hydrogen abstraction modes for toluene is achieved

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  19. Simultaneous Determination of Benzene and Toluene in Pesticide Emulsifiable Concentrate by Headspace GC-MS

    OpenAIRE

    Lidong Cao; Hua Jiang,; Jing Yang; Li Fan; Fengmin Li; Qiliang Huang

    2013-01-01

    The toxic inert ingredients in pesticide formulations are strictly regulated in many countries. In this paper, a simple and efficient headspace-gas chromatography-mass spectrometry (HSGC-MS) method using fluorobenzene as an internal standard (IS) for rapid simultaneous determination of benzene and toluene in pesticide emulsifiable concentrate (EC) was established. The headspace and GC-MS conditions were investigated and developed. A nonpolar fused silica Rtx-5 capillary column (30?m × 0.20?mm...

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

    International Nuclear Information System (INIS)

    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 ?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)

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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)

  3. Coordination chemistry of metal surfaces. 3. Benzene and toluene interactions with nickel surfaces

    International Nuclear Information System (INIS)

    Ni surfaces were the low Miller index planes (111), (110), and (100) and the stepped and stepped-kinked surfaces 9(111) x (111) and 7(111) x (310). Effects of surface C and O were established for low surface coverages. Benzene chemisorption was fully associative (molecular) on Ni(111) up to 1000C; no H-D exchange occurred between C6H6 and C6D6 up to 1000C. Up to 1000C, benzene was displaced as C6H6(g) by P(CH3)3. Benzene reversible thermal desorption occurred at 115 to 1250C, accompanied by extensive irreversible decomposition to H2(g) + Ni(111)-C. Analogous behavior was observed for benzene chemisorbed on the stepped and stepped-kinked surface. On the (110) surface, the benzene thermal desorption and benzene chemical displacement by P(CH3)3 was comparable to the stepped-kinked surface. Chemisorption of benzene on Ni(100) was differentiated from the other surfaces: the degree of thermal reversibility was higher than and the temperature for the thermal desorption maximum was 1000C higher than that for Ni(111). H-D exchange did not occur with D2 + C6H6 and with C6H6 + C6D6 on Ni(100). Toluene chemisorption on all the nickel surfaces was thermally irreversible and toluene was not displaced from these surfaces by strong field ligands like P(CH3)3 and CH3NC. Heating the Ni-toluene surfaces led to hydrogen evolution. For the decomposition of C6D5CD3 on Ni(111) there were two D2 thermal desorption maxima, 130 and 1900C. For the analogous decomposition of C6H5CD3 and C6D5CH3 respectively, there were single D2 desorption curves with maxima at 130 and 1850C, respectively. Thus, aliphatic C-H bonds are broken first and no aromatic C-H bond is broken until near 1600C. Identical behavior was observed for the stepped and stepped-kinked surfaces, and an analogous behavior was observed for the (100) surface

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

    Science.gov (United States)

    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

  5. Carbon and hydrogen isotope fractionation of benzene and toluene during hydrophobic sorption in multistep batch experiments.

    Science.gov (United States)

    Imfeld, G; Kopinke, F-D; Fischer, A; Richnow, H-H

    2014-07-01

    The application of compound-specific stable isotope analysis (CSIA) for evaluating degradation of organic pollutants in the field implies that other processes affecting pollutant concentration are minor with respect to isotope fractionation. Sorption is associated with minor isotope fractionation and pollutants may undergo successive sorption-desorption steps during their migration in aquifers. However, little is known about isotope fractionation of BTEX compounds after consecutive sorption steps. Here, we show that partitioning of benzene and toluene between water and organic sorbents (i.e. 1-octanol, dichloromethane, cyclohexane, hexanoic acid and Amberlite XAD-2) generally exhibits very small carbon and hydrogen isotope effects in multistep batch experiments. However, carbon and hydrogen isotope fractionation was observed for the benzene-octanol pair after several sorption steps (??(13)C=1.6 ± 0.3‰ and ??(2)H=88 ± 3‰), yielding isotope fractionation factors of ?C=1.0030 ± 0.0005 and ?H=1.195 ± 0.026. Our results indicate that the cumulative effect of successive hydrophobic partitioning steps in an aquifer generally results in insignificant isotope fractionation for benzene and toluene. However, significant carbon and hydrogen isotope fractionation cannot be excluded for specific sorbate-sorbent pairs, such as sorbates with ?-electrons and sorbents with OH-groups. Consequently, functional groups of sedimentary organic matter (SOM) may specifically interact with BTEX compounds migrating in an aquifer, thereby resulting in potentially relevant isotope fractionation. PMID:24726480

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

    Energy Technology Data Exchange (ETDEWEB)

    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).

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

  9. Ambient air levels and the exposure of children to benzene, toluene, and xylenes in Denmark.

    Science.gov (United States)

    Raaschou-Nielsen, O; Lohse, C; Thomsen, B L; Skov, H; Olsen, J H

    1997-11-01

    The aims of the study were to evaluate if the front-door concentrations of benzene, toluene, and xylenes can be used to classify the personal exposures of Danish children and to identify factors that affect their personal exposure. Average concentrations were measured over 1 week with diffusive samplers, and the personal exposures of 98 children and the concentrations outside the front doors of their homes were measured simultaneously. Time and activity patterns were noted in diaries. The front-door concentrations were significantly higher in Copenhagen than in rural areas (all P motocross, moped driving, and refueling of cars. PMID:9417846

  10. Benzene, toluene and xylenes levels in new and used vehicles of the same model.

    Science.gov (United States)

    Faber, Joanna; Brodzik, Krzysztof; Golda-Kopek, Anna; Lomankiewicz, Damian

    2013-11-01

    The aim of this work was to determine the level of benzene, toluene, o-xylene and m, p-xylene (BTX) in air samples collected from the cabins of new and used vehicles of the same model. Ten new vehicles were examined in order to check interior emission from materials used to equip the passenger compartment. In order to compare and define the impact of exhaust gases, air samples were also collected from two used cars, at different mileages (up to 20,000 km). All vehicles tested were of the same type. Samples were collected onto Carbograph 1TD sorbent, thermally desorbed and examined with the use of gas chromatography with flame ionisation and mass spectrometry detectors. All results obtained were referred to Polish and German requirements for indoor air quality (both in public buildings and in workspace environments). Average benzene, toluene, o-xylene and m, p-xylene concentrations in new cars were determined at the level of 11.8 microg/m3, 82.7 micro/m3, 21.2 microg/m3 and 89.5 micro/m3, respectively. In the used cars, BTX concentration increased with increasing vehicle mileage. The most significant increase of BTX concentration was observed above 11,000 km mileage. PMID:24552062

  11. Energy resolution measurements of benzene, toluene and cyclohexane scintillators for monoenergetic ?-rays

    International Nuclear Information System (INIS)

    Energy resolution and difference of the maximum energy of Compton electrons from the half-height of the Compton edge was measured experimentally for benzene (C6H6), cyclohexane (C6H12) and toluene scintillators for monoenergetic ?-rays using a ?-? coincidence technique. For 0.5-1.2 MeV ?-rays, the energy resolution for C6H6, C6H12 and toluene scintillators varies from 23.8-12.6%, 28.6-2.5% and 23.5-4.6%, respectively. The corresponding energy difference between the maximum Compton electron energy and the half height of the Compton edge for C6H6, C6H12 and toluene scintillators varies from 13.2-7.6%, 17.7-10.2% and 10.2-6.8%, respectively. The energy resolution of the C6H6 detector agrees within 5-10% of that obtained with an identical C6D6 scintillator. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, L.

    2001-02-01

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

  13. Removal of benzene and toluene in horizontal-flow anaerobic immobilized biomass reactor (HAIBR) in the presence of sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Cattony, E.B.M.; Chinalia, F.A.; Adorno, M.A.T.; Moraes, E.M.; Zaiat, M.; Foresti, E.; Varesche, M.B.A. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Biological Processes Laboratory

    2004-07-01

    The removal of toluene and benzene from organic waste by microorganisms was tested in two bioreactors. Two horizontal-flow anaerobic immobilized biomass (HAIB) reactors were fed with Zinder medium to stimulate anaerobic sulfate-reducing bacteria (SRB). The chemical oxygen demand (COD) and sulfate analysis were assessed and acetic acid, toluene and benzene were analyzed in gas chromatography. Microbial communities were characterized by fluorescence, optical electron microscopy and molecular biology analysis. The HAIB reactors achieved steady state within 2 weeks following hydrocarbon compound amendments. Depletion of sulfate was achieved after this time, along with removal of toluene and benzene. The inflow COD for both reactors was more than 95 per cent. The HAIB reactor operated under sulfidogenic conditions. It was concluded that the use of benzene and toluene is an efficient and cost-effective method for treating contaminated water, particularly for tropical developing countries. The study emphasized the importance of SRB populations in bioreactors to degrade organic aromatics under oxygen reduced conditions. 10 refs., 4 figs.

  14. Simplified sonochemical preparation of titania embedded with selected metals for purification of benzene and toluene.

    Science.gov (United States)

    Lee, Joon Yeob; Jo, Wan-Kuen

    2016-01-01

    Titania (TiO2) photocatalysts, each embedded with one of six metals (Ag, Ce, Co, Fe, Mg, and Mn), were prepared using a simplified ultrasonic process. The characteristics of the prepared metal-embedded TiO2 (metal-TiO2) were determined using transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, photoluminescence emission spectroscopy, UV-visible spectroscopy, and nitrogen adsorption-desorption. Except for Co-TiO2, the metal-TiO2 photocatalysts showed improved performance for the decomposition of gaseous benzene and toluene, which are two of the most problematic indoor air pollutants that can cause a variety of adverse health symptoms, under daylight lamp irradiation. Photocatalytic activity was greatest for the Mg-TiO2 sample, followed by, in order, the Ag-TiO2, Ce-TiO2, Fe-TiO2, Mn-TiO2, unmodified TiO2, and Co-TiO2 samples. Although Mg-TiO2 showed the least redshift in its light absorption and the highest electron-hole recombination rate among the metal-TiO2 photocatalysts, it yielded the highest photocatalytic activity, likely because of its increased adsorption capacity and anatase composition. The degradation of benzene and toluene over Mg-TiO2 improved as ultrasound treatment amplitude increased from 20 to 37 ?m, then decreased gradually as amplitude was further increased to 49 ?m. Degradation efficiency also improved as ultrasound operation time increased from 30 to 60 min, then decreased gradually as amplitude was further increased to 90 min. Overall, this process could be utilized to prepare metal-TiO2 photocatalysts with improved performance for the decomposition of gas phase pollutants under daylight lamp irradiation. PMID:26384905

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

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

    2014-12-01

    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

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

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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¯¹ soil for benzene, toluene, ethylbenzene and xylenes are below the guiding values that range from 0.15 to 95 mg Kg¯¹ 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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Bravo, Humberto; Sosa, Rodolfo; Sánchez, Pablo; Bueno, Emma; González, Laura

    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.

  3. 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)}

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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 ?g/L for benzene, 0.70 ?g/L for toluene, and 1.54 ?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 ?g/L to 2.0 ?g/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)

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  7. Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and Xylene Compounds by Dechloromonas Strain RCB

    OpenAIRE

    Chakraborty, Romy; O'Connor, Susan M.; Chan, Emily; Coates, John D.

    2005-01-01

    Dechloromonas strain RCB has been shown to be capable of anaerobic degradation of benzene coupled to nitrate reduction. As a continuation of these studies, the metabolic versatility and hydrocarbon biodegradative capability of this organism were investigated. The results of these revealed that in addition to nitrate, strain RCB could alternatively degrade benzene both aerobically and anaerobically with perchlorate or chlorate [(per)chlorate] as a suitable electron acceptor. Furthermore, with ...

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

    Czech Academy of Sciences Publication Activity Database

    Šperlingová, I.; Dabrowská, L.; Stránský, V.; Ku?era, Jan; Tichý, M.

    2007-01-01

    Ro?. 387, ?. 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. Spatial variability in levels of benzene, formaldehyde, and total benzene, toluene, ethylbenzene and xylenes in New York City: a land-use regression study

    Directory of Open Access Journals (Sweden)

    Kheirbek Iyad

    2012-07-01

    Full Text Available Abstract Background Hazardous air pollutant exposures are common in urban areas contributing to increased risk of cancer and other adverse health outcomes. While recent analyses indicate that New York City residents experience significantly higher cancer risks attributable to hazardous air pollutant exposures than the United States as a whole, limited data exist to assess intra-urban variability in air toxics exposures. Methods To assess intra-urban spatial variability in exposures to common hazardous air pollutants, street-level air sampling for volatile organic compounds and aldehydes was conducted at 70 sites throughout New York City during the spring of 2011. Land-use regression models were developed using a subset of 59 sites and validated against the remaining 11 sites to describe the relationship between concentrations of benzene, total BTEX (benzene, toluene, ethylbenzene, xylenes and formaldehyde to indicators of local sources, adjusting for temporal variation. Results Total BTEX levels exhibited the most spatial variability, followed by benzene and formaldehyde (coefficient of variation of temporally adjusted measurements of 0.57, 0.35, 0.22, respectively. Total roadway length within 100?m, traffic signal density within 400?m of monitoring sites, and an indicator of temporal variation explained 65% of the total variability in benzene while 70% of the total variability in BTEX was accounted for by traffic signal density within 450?m, density of permitted solvent-use industries within 500?m, and an indicator of temporal variation. Measures of temporal variation, traffic signal density within 400?m, road length within 100?m, and interior building area within 100?m (indicator of heating fuel combustion predicted 83% of the total variability of formaldehyde. The models built with the modeling subset were found to predict concentrations well, predicting 62% to 68% of monitored values at validation sites. Conclusions Traffic and point source emissions cause substantial variation in street-level exposures to common toxic volatile organic compounds in New York City. Land-use regression models were successfully developed for benzene, formaldehyde, and total BTEX using spatial indicators of on-road vehicle emissions and emissions from stationary sources. These estimates will improve the understanding of health effects of individual pollutants in complex urban pollutant mixtures and inform local air quality improvement efforts that reduce disparities in exposure.

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

    Science.gov (United States)

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

    2011-08-15

    Simultaneous and molecularly selective parts-per-billion detection of benzene, toluene, and xylenes (BTX) using a thermal desorption (TD)-FTIR hollow waveguide (HWG) trace gas sensor is demonstrated here for the first time combining laboratory calibration with real-world sample analysis in field. A calibration range of 100-1000 ppb analyte/N(2) was developed and applied for predicting the concentration of blinded environmental air samples within the same concentration range, and demonstrate close agreement with the validation method used here, GC-FID. The analyte concentration prediction capability of the TD-FTIR-HWG trace gas sensor also compares well with the industrial standard and other experimental techniques including GC-PID, ultrafast GC-FID, and GC-DMS, which were simultaneously operated in the field. With the advent of a quantum cascade laser with emission frequencies specifically tailored to efficiently overlap benzene absorption as the most relevant analyte, the overall sensor footprint could be considerably reduced to ultimately yield hand-held trace gas sensors facilitating direct and real-time detection of BTX in air down to low ppb levels. PMID:21612210

  11. Bubble point measurements of binary mixtures formed by ethyl benzene with selected compounds at 95.35 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Vittal Prasad, T.E. [Properties Group, Chemical Engineering Laboratory, Indian Institute of Chemical Technology, Hyderabad 500 007 (India); Vasavi, M.; Jyotsna, M.; Jhansi, V.; Smitha, G. [Bhoj Reddy Engineering College for Women, Hyderabad 500 059 (India); Prasad, D.H.L. [Properties Group, Chemical Engineering Laboratory, Indian Institute of Chemical Technology, Hyderabad 500 007 (India)], E-mail: dasika@iict.res.in

    2008-09-15

    Bubble point temperatures (at 95.35 kPa) over the entire composition range were measured for the binary mixtures formed by ethyl benzene with: acetyl acetone, o-, and p-cresols, 1-hexanol, and tetraethoxysilane, employing a Swietoslawski type ebulliometer. Wilson equation was used to represent the measured liquid phase composition versus bubble point temperature data, and the computed values of the vapor phase mole fractions, activity coefficients, and excess Gibbs free energy were tabulated and briefly discussed.

  12. Ceria Zirconia Mixed Oxides Prepared by Hydrothermal Templating Method for the Oxidation of Ethyl Benzene

    Directory of Open Access Journals (Sweden)

    Cimi A Daniel

    2013-12-01

    Full Text Available CeO2–ZrO2 oxides were prepared by the surfactant-templated method using cetyl trimethyl ammonium bromide (CTAB as template. These were characterized by XRD, FT-IR, TEM, SEM, BET and TPD-CO2. The XRD data showed that as prepared CeO2-ZrO2 powder particles have single phase cubic fluorite structure. HRTEM shows mesoscopic ordering. Average particle size is 12-13 nm as calculated from particle histogram. The nitrogen adsorption/desorption isotherm were classified to be type IV isotherm, typical of mesoporous material. The presence of uni-modal mesopores are confirmed by the pore size distribution which shows pore distribution at around 60 A°. The catalytic activities of the prepared material were tested in liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide (TBHP as an oxidant. Ceria zirconia catalyst modified with chromium was active for ethylbenzene conversion (65.3% with 77% selectivity towards acetophenone.  © 2013 BCREC UNDIP. All rights reservedReceived: 4th June 2013; Revised: 20th July 2013; Accepted: 18th August 2013[How to Cite: Daniel, C.A., Sugunan, S. (2013. Ceria Zirconia Mixed Oxides Prepared by Hydrothermal Templating Method for the Oxidation of Ethyl Benzene. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 97-104. (doi:10.9767/bcrec.8.2.5053.97-104][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.5053.97-104

  13. An effort to test the embryotoxicity of benzene, toluene, xylene, and formaldehyde to murine embryonic stem cells using airborne exposure technique.

    Science.gov (United States)

    Shen, Shuijie; Yuan, Lingmin; Zeng, Su

    2009-10-01

    Benzene, toluene, xylene, and formaldehyde are well-known indoor air pollutants, especially after house decoration. They are also common pollutants in the working places of the plastic industry, chemical industry, and leather industry. It has been reported that these pollutants cause people to be irritated, sick, experience a headache, and be dizzy. They also have the potential to induce asthma, aplastic anemia, and leukemia, even cause abortion or fetus malformation in humans. In this study, the airborne toxicity of benzene, toluene, xylene, and formaldehyde to murine embryonic stem cells (mES cells) were tested using airborne exposure technique to evaluate the mES cell airborne exposure model on embryotoxicity prediction. Briefly, mES cells were cultured on Transwell inserts and were exposed to an airborne surrounding of test chemicals in a chamber for 1 h at 37 degrees C. Cytotoxicity was determined using the MTT assay after further culture for 18 h at 37 degrees C in normal medium. The airborne IC(50) (50% inhibition concentration) of benzene, toluene, xylene, and formaldehyde derived from the fitted dose-response curves were 17,400 +/- 1290, 16,000 +/- 250, 4680 +/- 500, and 620 +/- 310 ppm, respectively. Formaldehyde was found to be the compound most toxic to mES cells compared to benzene homologues. The toxicity data had good correlation with the in vivo data. The results showed that the mES airborne exposure model may be used to predict embryotoxicity of volatile organic compounds. PMID:19635035

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    DEFF Research Database (Denmark)

    Dueholm, Morten Simonsen; Albertsen, Mads

    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 closely related (100.0% average nucleotide identity). Both strains contain extensive integration of phage elements, with the main difference being insertion of additional phage elements in the SB3078 genome.

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

    International Nuclear Information System (INIS)

    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 ?g/m3, respectively) and from 16 school sites with moderate concentrations (means: 2.6, 32.2, and 5.7 ?g/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

  19. Transgenic plants of Petunia hybrida harboring the CYP2E1 gene efficiently remove benzene and toluene pollutants and improve resistance to formaldehyde

    Scientific Electronic Library Online (English)

    Daoxiang, Zhang; Taihe, Xiang; Li, Peihan; Lumin, Bao.

    Full Text Available The CYP2E1 protein belongs to the P450 enzymes family and plays an important role in the metabolism of small molecular and organic pollutants. In this study we generated CYP2E1 transgenic plants of Petunia using Agrobacterium rhizogenes K599. PCR analysis confirmed that the regenerated plants contai [...] ned the CYP2E1 transgene and the rolB gene of the Ri plasmid. Southern blotting revealed the presence of multiple copies of CYP2E1 in the genome of transgenic plants. Fluorescent quantitative PCR revealed exogenous CYP2E1 gene expression in CYP2E1 transgenic plants at various levels, whereas no like expression was detected in either GUS transgenic plants or wild-types. The absorption of benzene and toluene by transgenic plants was analyzed through quantitative gas chromatography. Transgenic plants with high CYP2E1 expression showed a significant increase in absorption capacity of environmental benzene and toluene, compared to control GUS transgenic and wild type plants. Furthermore, these plants also presented obvious improved resistance to formaldehyde. This study, besides being the first to reveal that the CYP2E1 gene enhances plant resistance to formaldehyde, also furnishes a new method for reducing pollutants, such as benzene, toluene and formaldehyde, by using transgenic flowering horticultural plants.

  20. Volumetric properties of binary liquid mixtures: Application of the Prigogine-Flory-Patterson theory to excess molar volumes of dichloromethane with benzene or toluene

    International Nuclear Information System (INIS)

    The values of the density were measured for binary liquid mixtures of benzene and toluene with dichloromethane over entire range of concentration using a vibrating-tube densimeter at T = (288.15, 293.15, 298.15, and 303.15) K and atmospheric pressure. The excess molar volumes, calculated from the density results, are positive for the systems of dichloromethane with benzene over the whole concentration range and present an approximate sigmoid curve for the dichloromethane with toluene. The VmE values have been fitted to the Redlich-Kister polynomial equation, and other volumetric properties such as the partial molar volumes, Vi-bar, the apparent molar volume, V?i, and the partial molar excess volumes at infinite dilution, (ViE-bar)?, were calculated over the whole composition range. The Prigogine-Flory-Patterson (PFP) theory and its applicability in predicting VmE at T = 298.15 K are tested. Good agreement was found for the mixtures dichloromethane with benzene. For the mixtures dichloromethane with toluene, which shows an approximate S-shaped VmE behaviour, the correlation fails.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Stress response, biotransformation effort, and immunotoxicity in captive birds exposed to inhaled benzene, toluene, nitrogen dioxide, and sulfur dioxide.

    Science.gov (United States)

    Cruz-Martinez, Luis; Smits, Judit E G; Fernie, Kim

    2015-02-01

    In the oil sands of Alberta, Canada, toxicology research has largely neglected the effects of air contaminants on biota. Captive Japanese quail (Coturnix c. japonica) and American kestrels (Falco sparverius) were exposed to mixtures of volatile organic compounds and oxidizing agents (benzene, toluene, NO2 and SO2) in a whole-body inhalation chamber, to test for toxicological responses. Hepatic biotransformation measured through 7-ethoxyresorufin-O-dealkylase (EROD) tended to be increased in exposed kestrels (p=0.06) but not in quail (p=0.15). Plasma corticosterone was increased in the low dose group for quail on the final day of exposure (p=0.0001), and midway through the exposure period in exposed kestrels (p=0.04). For both species, there was no alteration of T and B-cell responses, immune organ mass, or histology of immune organs (p>0.05). This study provides baseline information valuable to complement toxicology studies and provides a better understanding of potential health effects on wild avifauna. PMID:25463874

  3. Biodegradation kinetics of benzene and toluene as single and mixed substrate: estimation of biokinetics parameters by applying particle swarm optimization

    Scientific Electronic Library Online (English)

    D.E.G., Trigueros; A.N., Módenes; M.A.S.S., Ravagnani.

    2010-07-01

    Full Text Available This paper aims to describe the microbial biodegradation kinetics of benzene and toluene as single and mixed substrates. Particle Swarm Optimization (PSO) is used as the parameter identification procedure. Initially, the Monod and Andrews models were used. To predict the interactions between the sub [...] strates, more sophisticated models of inhibition and the SKIP model were applied. The development of the changes on the competitive inhibition model was also described. The models were evaluated using experimental data on Pseudomonas putida F1 activity found in the literature. Simulation results showed that the best description of the biodegradation process of a pure substrate can be achieved by the Andrews model and in the case of a mixture by the modified competitive inhibition model. These results were expected because both substrates are catabolized by the same metabolic pathway through Pseudomonas putida F1. The SKIP model also captured the substrate interactions well. The performance of PSO was excellent and the methodology developed in this work can be considered as very efficient.

  4. Densities, viscosities, and excess properties of (N-methylmorpholine + cyclohexane, + benzene, and + toluene) at T = (298.15, 303.15, 313.15, 323.15) K

    International Nuclear Information System (INIS)

    Densities, ?, and viscosities, ?, of binary mixtures (N-methylmorpholine + benzene, + toluene, and + cyclohexane) were measured over the whole mole fraction range at T = (298.15, 303.15, 313.15, 323.15) K. Densities and viscosities were used to compute the excess molar volumes VE, viscosity deviation ??, and the excess free energies of activation for viscous flow ?G*E. These data have been fitted to Redlich-Kister polynomial equation to derive the coefficients and estimate the standard deviation values. A discussion on these quantities in terms of molecular interactions is reported

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

    Indian Academy of Sciences (India)

    Ramin Ghorbani-Vaghei; Somaye Hajinazari

    2013-03-01

    Poly(,$N'$-dibromo--ethyl-benzene-1,3-disulphonamide) [PBBS] and ,,$N'$,$N'$-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.

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

    International Nuclear Information System (INIS)

    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 (?-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

  7. 2-{(E-1-[2-(4-Nitrophenylhydrazin-1-ylidene]ethyl}benzene-1,3-diol

    Directory of Open Access Journals (Sweden)

    Edward R. T. Tiekink

    2012-03-01

    Full Text Available The title compound, C14H13N3O4, is close to planar, the dihedral angle between the terminal benzene rings being 5.80?(16°; the nitro group is coplanar with the benzene ring to which it is bonded [O—N—C—C torsion angle = ?177.3?(3°]. The hydroxy group forms an intramolecular hydrogen bond with the imine N atom, and the conformation about the imine bond is E. In the crystal, layers in the (101 plane with an undulating topology are formed by O—H...O and N—H...O hydrogen bonds along with C—H...O interactions. Centrosymmetrically related layers are connected via ?–? interactions [ring centroid–centroid distance = 3.5739?(19?Å] into double layers.

  8. Determination of benzene, toluene and N-hexane in urine and blood by headspace solid-phase microextration/gas-chromatography for the biomonitoring of occupational exposure

    Scientific Electronic Library Online (English)

    Paulo C. F. de Lima, Gomes; Éverton D., D' Andrea; Camila B., Mendes; Maria Elisa P. B. de, Siqueira.

    Full Text Available A análise de tolueno, benzeno e n-hexano inalterados em urina e sangue humano é uma ferramenta para avaliar a exposição ocupacional a esses solventes. Um método simples usando microextração em fase sólida acoplada ao headspace (HS-SPME), usando fibras de carboxeno/polidimetilsiloxano (CAR-PDMS) e PD [...] MS, para análise simultânea por cromatografia gasosa de tolueno, benzeno e n-hexano em urina e em sangue foi desenvolvido com intuito de realizar a monitorização biológica de indivíduos expostos ocupacionalmente a esses solventes. O método foi aplicado na análise de amostras de trabalhadores que utilizavam colas, contendo solventes, na recuperação de calçados. O tolueno foi detectado em todas as amostras de sangue coletadas em sapatarias quando se utilizou a fibra de CAR-PDMS (16,0-55,2 ?g L-1, n=7) e o n-hexano foi detectado em duas amostras (33,0 and 41,3 ?g L-1). O benzeno não foi detectado em nenhuma das amostras de sangue e/ou urina. Nenhum dos solventes pode ser quantificado nas amostras de urina. Abstract in english Analysis of unchanged toluene, benzene and n-hexane in human blood and urine can be useful to evaluate occupational exposure to these solvents. A simple method was developed using headspace-solid phase microextraction (HS-SPME) for simultaneous gas-chromatography analysis of toluene, benzene and n-h [...] exane in urine and blood; with purpose of biological monitoring of occupational exposure. Carboxen/polidimethylsiloxane fiber (CAR-PDMS) and PDMS fiber coating were employed in this analysis. Blood and urine samples were collected from handling glue workers. The toluene was detected in all blood samples collected from workers handling glue in shoe repair shops, when using CAR-PDMS fibers (16.0-55.2 ?g L-1, n=7). n-Hexane was only detected in two blood samples (33.0 and 41.3 ?g L-1) and benzene was not detected in anyone. No solvent could be quantified in urine samples.

  9. Preliminary study to prepare a reference material of toluene metabolite - o-cresol and benzene metabolite-phenol - in human.

    Czech Academy of Sciences Publication Activity Database

    Šperlingová, I.; Dabrowská, L.; Stránský, V.; Ku?era, Jan; Tichý, M.

    2006-01-01

    Ro?. 11, ?. 5 (2006), s. 231-235. ISSN 0949-1775 R&D Projects: GA MZd NR7831 Institutional research plan: CEZ:AV0Z10480505 Keywords : reference material * toluene metabolites * o-cresol Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.640, year: 2006

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    Flamys Lena do N. Silva; José Ribeiro dos Santos Jr.; José Machado Moita Neto; Rosa Lina G. do N. P. da Silva; Danilo Luiz Flumignan; José 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 ºC. Its composition varies with the kind of crude oil and the type of refinery process that they undergone. Aromatics hydrocarbons, in particular benzene, toluene, ethylbenzene and isomeric xylenes (BTEX) are the toxic group constituents presents. GC-FID was employed to quantify these hydrocarbons in 50 ...

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

    Scientific Electronic Library Online (English)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Marcelo Henrique Otenio

    2005-09-01

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

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

    Scientific Electronic Library Online (English)

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

    2005-09-01

    Full Text Available Meio mineral líquido contendo benzeno (B) ou tolueno (T) ou xileno (X) a 100 mg L-1 e suas misturas de BT, BX e TX (50 + 50 mg L-1 cada mistura) e BTX (33,3 + 33,3 + 33,3 mg L-1 cada mistura) foram utilizados para avaliar a atividade de degradação de B, T e X por Pseudomonas putida CCMI 852 contendo [...] um plasmídeo TOL. Após 18 a 24 horas de homogenização da mistura, o inoculo foi adicionado e o decréscimo da concentração dos solventes foi determinado entre 24 e 25 horas por GC. Pseudomonas putida CCMI 852 foi capaz de metabolizar T e X, mas não B. Na mistura BTX, B não foi metabolizado também e a velocidade de degradação de T e X decresceu cerca de 50% comparado com soluções contendo apenas T ou X. Abstract in english 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%.

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

    Directory of Open Access Journals (Sweden)

    Flamys Lena do N. Silva

    2009-01-01

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

  18. 2-{(E-1-[2-(2-Nitrophenylhydrazin-1-ylidene]ethyl}benzene-1,3-diol monohydrate

    Directory of Open Access Journals (Sweden)

    Edward R. T. Tiekink

    2012-03-01

    Full Text Available The hydrazone molecule in title monohydrate, C14H13N3O4·H2O, is almost coplanar, the dihedral angle between the terminal benzene rings being 3.22?(15°; the nitro group is coplanar with the benzene ring to which it is bonded [O—N—C—C = ?2.8?(4°]. The hydroxy group forms an intramolecular hydrogen bond with the imine N atom, and the conformation about the imine bond [1.305?(3?Å] is E. In the crystal, supramolecular layers in the (203 plane are connected into a double layer via water–nitro O—H...O hydrogen bonds, along with ?–? interactions [ring centroid–centroid distance = 3.7859?(19?Å].

  19. Design and synthesis of (E)-1-((3-ethyl-2,4,4-trimethylcyclohex-2- enylidene)methyl-4-substituted benzenes from 1-(2,6,6-trimethylcyclohex-1-enyl)ethanol†

    OpenAIRE

    Das, Bhaskar C; SAKKARAPALAYAM M MAHALINGAM; Evans, Todd; George W. Kabalka; Anguiano, J.; Hema, K.

    2009-01-01

    A novel strategy for synthesizing (E)-1-((3-ethyl-2,4,4- trimethylcyclohex-2-enylidene)methyl-4-substituted benzenes from 1-(2,6,6-trimethylcyclohex-1-enyl)ethanol 3 has been developed; the allylic alcohol 3 was treated with PPh3·HBr in methanol followed by aldehydes in the presence of a base and furnished the 1,3-dienes in moderate to good yields (79–86%).

  20. Design and synthesis of (E)-1-((3-ethyl-2,4,4-trimethylcyclohex-2- enylidene)methyl-4-substituted benzenes from 1-(2,6,6-trimethylcyclohex-1-enyl)ethanol†

    Science.gov (United States)

    Mahalingam, Sakkarapalayam M.; Kabalka, George W.; Anguiano, J.; Hema, K.

    2011-01-01

    A novel strategy for synthesizing (E)-1-((3-ethyl-2,4,4- trimethylcyclohex-2-enylidene)methyl-4-substituted benzenes from 1-(2,6,6-trimethylcyclohex-1-enyl)ethanol 3 has been developed; the allylic alcohol 3 was treated with PPh3·HBr in methanol followed by aldehydes in the presence of a base and furnished the 1,3-dienes in moderate to good yields (79–86%). PMID:19360170

  1. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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

    International Nuclear Information System (INIS)

    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

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

    Scientific Electronic Library Online (English)

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

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

  4. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    Science.gov (United States)

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes. PMID:26322761

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

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Kelly Cristina Santana de

    2006-07-01

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

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

    International Nuclear Information System (INIS)

    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

  7. (Liquid + liquid) equilibria in the binary systems (aliphatic, or aromatic hydrocarbons + 1-ethyl-3-methylimidazolium ethylsulfate, or 1-butyl-3-methylimidazolium methylsulfate ionic liquids)

    International Nuclear Information System (INIS)

    (Liquid + liquid) equilibria of 14 binary systems composed of n-hexane, n-heptane, benzene, toluene, o-xylene, m-xylene, or p-xylene and 1-ethyl-3-methylimidazolium ethylsulfate, [emim]EtSO4, or 1-butyl-3-methylimidazolium methylsulfate, [bmim]MeSO4, ionic liquids have been done in the temperature range from (293.2 to 333.2) K. The solubility of aliphatic is less than those of the aromatic hydrocarbons. In particular, the solubility of hydrocarbons in both ionic liquids increases with the temperature in the order n-heptane < n-hexane < m-xylene < p-xylene < o-xylene < toluene < benzene. Considering the high solubility of aromatics and the low solubility of aliphatic hydrocarbons as well as totally immiscibility of the ionic liquids in all hydrocarbons, these new green solvents may be used as potentials extracting solvents for the separation of aromatic and aliphatic hydrocarbons.

  8. (Liquid + liquid) equilibria in the binary systems (aliphatic, or aromatic hydrocarbons + 1-ethyl-3-methylimidazolium ethylsulfate, or 1-butyl-3-methylimidazolium methylsulfate ionic liquids)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Julian, E-mail: jgarcia@quim.ucm.e [Department of Chemical Engineering, Complutense University of Madrid, E-28040 Madrid (Spain); Torrecilla, Jose S.; Fernandez, Adela; Oliet, Mercedes; Rodriguez, Francisco [Department of Chemical Engineering, Complutense University of Madrid, E-28040 Madrid (Spain)

    2010-01-15

    (Liquid + liquid) equilibria of 14 binary systems composed of n-hexane, n-heptane, benzene, toluene, o-xylene, m-xylene, or p-xylene and 1-ethyl-3-methylimidazolium ethylsulfate, [emim]EtSO{sub 4}, or 1-butyl-3-methylimidazolium methylsulfate, [bmim]MeSO{sub 4}, ionic liquids have been done in the temperature range from (293.2 to 333.2) K. The solubility of aliphatic is less than those of the aromatic hydrocarbons. In particular, the solubility of hydrocarbons in both ionic liquids increases with the temperature in the order n-heptane < n-hexane < m-xylene < p-xylene < o-xylene < toluene < benzene. Considering the high solubility of aromatics and the low solubility of aliphatic hydrocarbons as well as totally immiscibility of the ionic liquids in all hydrocarbons, these new green solvents may be used as potentials extracting solvents for the separation of aromatic and aliphatic hydrocarbons.

  9. Toulouse urban area aromatic volatile organic compounds: benzene, toluene, xylenes (BTX) and nitrogen dioxide distribution study; Etude de la distribution atmospherique de composes organiques volatils aromatiques: benzene, toluene, xylenes (BTX) et du dioxyde d'azote sur l'agglomeration toulousaine

    Energy Technology Data Exchange (ETDEWEB)

    Meybeck, M.; Della Massa, J.P. [Observatoire Regional de l' Air en Midi Pyrenees, ORAMIP, 31 - Colomiers (France); Simon, V.; Grasset, E.; Torres, L. [Ecole Nationale Superieure de Chimie, 31 - Toulouse (France)

    2001-01-01

    The Observatoire regional de l'air en Midi-Pyrenees (ORAMIP) - a French regional atmospheric pollution measurements network - is in charge of air quality observation over the Toulouse urban area. Air quality measurements are done daily, using almost 80 analysers spread in more than thirty stations. Regulation for atmospheric pollution major indicators (ozone, nitrogen dioxide, sulphur dioxide...) has constantly evolved, and some compounds, e.g. benzene, have been regimented only very soon. ORAMIP, in partnership with the Ecole Nationale Superieure de Chimie de Toulouse (ENSCT) Chemistry Energy and Environment Laboratory, has carried out background BTX average concentrations measurements and evaluation by passive sampling study over Toulouse urban agglomeration. This study was carried out during two 1999 springtime and summer periods, over about sixty sites. These points were chosen among those of the NO{sub 2} measurements 1991-1992 and 1996-1997 ORAMIP campaigns. During the two periods, wind conditions were similar but it happened to rain during the first period. Although NO{sub 2} is decomposed in water, benzene, very few soluble, has some concentrations very close from one period to another. BTX pollution over Toulouse has in majority been produced by motor vehicle exhaust gases. The benzene average amount over the two Toulouse campaigns is equal to 2,2 {mu}g/m{sup 3}, very close to the French quality focus, and well under the average value of 5 {mu}g/m{sup 3} recommended by EEC countries, knowing that those regulations are given for a whole year. Moreover, 'P98/annual average' Khuner reports for 1999 NO{sub 2} settled urban captors and for punctual campaigns with passive samplers are similar (2,7 and 2). This study allowed us to show that BTX and NO{sub 2} in Toulouse atmosphere result essentially from exhaust gases: It would be important to measure benzene over annual periods, in order to know its exact values over such a period, and to observe its potential seasonal variations. Moreover, as far as the benzene limit value contained in gasoline went from 5 % to 1 % since 2000 January 1, it would be interesting to carry out again a passive sampling study to observe possible differences pointed out with such a reform. (authors)

  10. A one-pot catalyst-free synthesis of functionalized pyrrolo[1,2-a]quinoxaline derivatives from benzene-1,2-diamine, acetylenedicarboxylates and ethyl bromopyruvate

    OpenAIRE

    Piltan, Mohammad; Moradi, Loghman; Abasi, Golaleh; Zarei, Seyed Amir

    2013-01-01

    The catalyst-free multicomponent reaction of 1,2-diaminobenzene, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate forms pyrrolo[1,2-a]quinoxaline derivatives in good yields. Ethylenediamine also reacts under similar conditions to produce new pyrrolo[1,2-a]pyrazine derivatives.

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

    Directory of Open Access Journals (Sweden)

    Luis Haro-García

    2012-06-01

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

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

    Scientific Electronic Library Online (English)

    Luis, Haro-García; Nadia, Vélez-Zamora; Guadalupe, Aguilar-Madrid; Susana, Guerrero-Rivera; Vanessa, Sánchez-Escalante; Sergio R., Muñoz; Edward, Mezones-Holguín; Cuauhtémoc, Juárez-Pérez.

    2012-06-01

    Full Text Available Objetivos. Evaluar las tres series celulares sanguíneas e identificar la presencia de hipocromía, macrocitosis, leucopenia, linfocitopenia y trombocitopenia en un grupo de trabajadores expuestos a la mezcla de benceno-tolueno-xileno (BTX). Materiales y métodos. Estudio transversal donde se incluyó a [...] 97 trabajadores de una empresa de pinturas de México a los que se les realizó una biometría hemática convencional y les fue estimada la exposición a través de la dosis diaria potencial acumulada para vapores de BTX. Resultados. Del total de trabajadores, 19,6%, mostró macrocitosis, 18,6%, linfocitopenia, 10,3% hipocromía, 7,2% trombocitopenia y 5,2% leucopenia. La asociación cruda de macrocitosis con exposición a dosis alta de mezcla de BTX fue la única significativa (OR:3,6; IC95%: 1,08 - 13,9; p=0,02) y en la que se estructuró un modelo de regresión logística (OR:6,7; IC95%: 1,33 - 13,55; p:0,02) ajustada por edad, consumo de alcohol y tabaquismo. Conclusiones. Todos los componentes citohemáticos analizados mostraron cambios leves; que podrían estar asociados con la exposición a la mezcla de BTX. De ellos, la macrocitosis podría constituirse en una manifestación precoz que merece ser vigilada. Abstract in english 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 worker [...] s 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.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani-Vaghei, Ramin [Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of). Faculty of Chemistry. Dept. of Organic Chemistry; Veisi, Hojat [Payame Noor University, Songhor, Kermanshah (Iran, Islamic Republic of). Dept. of Chemistry

    2010-07-01

    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)

  14. Comparação entre injeção na coluna ("on-column") e headspace dinâmico na determinação de benzeno, tolueno e xilenos (BTX) em amostras de água / Comparison between on-column injection and dynamic headspace in the determination of Benzene, Toluene and Xylene (BTX) in water

    Scientific Electronic Library Online (English)

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

    2001-04-01

    Full Text Available [...] Abstract in english 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 det [...] ermination 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. Since they are toxic compounds even when present in low concentration levels, their determination is important in order to define the quality of the water. The sampling technique using headspace, coupled with gas chromatography as the separation method, showed to be suitable for BTX analysis in several samples at the mug/L (ppb) level.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Optimización de iones de fierro para la eliminación de piocianina en la reacción de degradación de Tolueno, Benceno y Fenol por Pseudomonas aeruginosa / Optimization of iron ions to eliminate pyocyanine in the degradation reaction of Toluene, Benzene and Phenol by Pseudomonas aeruginosa

    Scientific Electronic Library Online (English)

    María de L., Rangel-García; Jesús, Rodríguez-Martínez; Yolanda, Garza-García; José L., Martínez-Hernández.

    2010-03-01

    Full Text Available Una amplia gama de substancias xenobióticas representan un serio problema como contaminantes ambientales por su toxicidad; entre ellos los compuestos aromáticos pueden ser biodegradados por microorganismos que los usan como fuente de carbono y energía. El género Pseudomonas destaca por sus múltiples [...] aplicaciones biotecnológicas debido a su gran versatilidad metabólica; puede producir metabolitos útiles, transformaciones enzimáticas, biodegradación y biorremediación de suelos, y en aguas contaminadas con petróleo y plaguicidas. En esta investigación se usaron células de P. aeruginosa para degradar tolueno, benceno y fenol. La cepa fue cultivada en medio mineral sólido y se establecieron las concentraciones óptimas para el desarrollo de células viables: 0.31, 0.19 y 0.13 M para tolueno, benceno y fenol. Los ambientes con concentraciones limitadas de Fe(III) favorecen la producción de piocianina, pigmento que puede interferir en el método analítico de biodegradación de compuestos aromáticos. Este efecto fue eliminado aumentando la concentración de iones de fierro en el medio. Con base en lo anterior, se optimizó y estableció el medio de cultivo mineral con 0.04 g L-1 de FeSO4 en presencia de tolueno (0.03 M) y con esta concentración inicial la tasa de biodegradación fue 75 %. Las pruebas de degradación específicas para los compuestos aromáticos mostraron que la cepa de P. aeruginosa usada puede degradar tolueno, benceno y fenol. Las tasas de degradación fueron mayores para tolueno (58.4 %) y benceno (70.11 %) con concentraciones iniciales de 0.14 M y 0.16 M, y la degradación fue menor para fenol (24.65 %) con una concentración inicial 0.10 M. La capacidad degradadora de P. aeruginosa tuvo proporción directa con su crecimiento en presencia de los xenobióticos estudiados, mostrando una mayor cantidad de proteína celular en los cultivos con benceno (1.4982 mg mL-1), tolueno (0.8629 mg mL-1) y menor en los cultivos desarrollados en presencia de fenol (0.4431 mg mL-1); lo cual muestra que un deficiente desarrollo bacteriano (biomasa) influye en una subóptima biodegradación. Abstract in english A wide range of xenobiotic substances represent a serious problem as environmental pollutants because of their toxicity, among them are found aromatic compounds that can be biodegraded by microorganisms, which use them as their source of carbon and energy. The genus Pseudomonas is outstanding for it [...] s multiple biotechnological applications due to its remarkable metabolic versatility. It is capable of producing useful metabolites, enzymatic transformations, biodegradation and bioremediation in soil, as well as in water polluted with oil and pesticides. In this study, cells of P. aeruginosa were used to degrade toluene, benzene and phenol. The strain was cultivated in a solid mineral medium, and the following optimal concentrations were established for the development of viable cells: 0.31, 0.19, and 0.13 M for toluene, benzene and phenol. The environments with limited concentrations of Fe(III) favored the production of pyocyanine, a pigment that can interfere in the analytical method of aromatic compound biodegradation. This effect was eliminated by increasing the concentration of iron ions in the medium. On this basis, the mineral culture medium was optimized and established at 0.04 g L-1 FeSO4 in presence of toluene (0.03 M). With this initial concentration, a rate of biodegradation of 75 % was obtained. The specific degradation tests for the aromatic compounds showed that the P. aeruginosa strain used can degrade toluene, benzene and phenol. The rates of degradation were higher for toluene (58.4 °/o) and benzene (70.11 °/o) with the initial concentrations of 0.14 M and 0.16 M. Degradation was less for phenol (24.65 %) with an initial concentration of 0.10 M. The degrading capacity of P. aeruginosa was directly proportional to its growth in the presence of the xenobiotic substances studied. A larger amount of cell protein was exhibited in cultures with benzene (1.4982

  17. Studies on the mechanism of benzene toxicity

    International Nuclear Information System (INIS)

    Using the 59Fe uptake method of Lee et al. it was shown that erythropoiesis in female mice was inhibited following IP administration of benzene, hydroquinone, p-benzoquinone, and muconaldehyde. Toluene protected against the effects of benzene. Coadministration of phenol plus either hydroquinone or catechol resulted in greatly increased toxicity. The combination of metabolites most effective in reducing iron uptake was hydroquinone plus muconaldehyde. We have also shown that treating animals with benzene leads to the formation of adducts of bone marrow DNA as measured by the 32P-postlabeling technique

  18. Preparation of methylbenzene-ring-14C from benzene-14C on the basis of a microcatalytic process

    International Nuclear Information System (INIS)

    The known processes of benzene alkylation are relatively non-selective and give low yields. Therefore, they are not very suitable for the preparation of toluene- and xylene-ring-14C. Since the catalytic disproportionation of toluene into benzene and xylene is already used it was attempted to develop a procedure for the preparation of the above-mentioned 14C-compounds by reversing this reaction and using benzene-14C. The obtained results are presented and the developed synthesis is explained, using the preparation of toluene-ring-14C as an example. The average activity yield is 58%. (author)

  19. A comparison of the traffic-related benzene, toluene, xylene, and platinum exposure of children living in eastern and western German states; Vergleich der Belastung von Kindern aus den alten und neuen Bundeslaendern mit den verkehrsbedingten Schadstoffen Benzol, Toluol, Xylol und Platin

    Energy Technology Data Exchange (ETDEWEB)

    Begerow, J.; Dunemann, L. [Hygiene-Inst. des Ruhrgebiets, Inst. fuer Umwelthygiene und Umweltmedizin, Gelsenkirchen (Germany); Jermann, E.; Turfeld, M. [Medizinisches Inst. fuer Umwelthygiene, Duesseldorf (Germany); Sugiri, D.; Kraemer, U. [Inst. fuer Umweltmedizinische Forschung gGmbH, Duesseldorf (Germany); Schumann, G. [Hygieneinstitut Sachsen-Anhalt, Magdeburg (Germany)

    2003-07-01

    A field study was performed to assess the internal exposure of 149 five- to seven-year old children to traffic-related pollutants. The study was carried out in areas with high and low traffic density located in Western Germany (Essen/Ruhr, Borken, Northrhine-Westphalia) and Eastern Germany (Halle/Saale, Osterburg, Saxony-Anhalt). The benzene, toluene, o-, m-, p-xylene (BTX) concentrations in blood and the platinum excretion in urine served as markers for a traffic-related exposure. The parents were asked to answer a questionaire, which asked for such information as traffic density in the vicinity of the dwelling, redecoration activities inside the rooms, exposure to solvent containing household products, passive smoking, etc. The results of this study show, that emissions from traffic have a significant influence on the internal BTX burden of children. The internal benzene exposure is mainly a result of the benzene concentration in outdoor air, which as a result of the absence of indoor sources is reflected in indoor air. Regarding toluene and xylene indoor air concentrations were generally higher than those outdoors indicating that several relevant indoor sources exist. The urinary platinum (Pt)-excretion of the children from both high traffic areas (Essen/Ruhr, Halle/Saale) tended to higher values when compared with the Pt excretion of those children from the low-traffic areas. However, this differences were statistically not significant. The results of this study do not definitively prove whether emissions from automobile catalysts are responsible for the slightly higher Pt exposure of these children. Keywords: BTX; children; human biological monitoring; platinum; traffic-related exposure (orig.) [German] Im Rahmen des Human-Biomonitorings wurde die verkehrsbedingte interne Fremdstoffbelastung von 149 fuenf- bis siebenjaehrigen Kindern aus je einem hoch und einem niedrig mit Strassenverkehr belastetem Areal aus den alten Bundeslaendern (Essen/Ruhr, Borken, beide Nordrhein-Westfalen) sowie aus den neuen Bundeslaendern (Halle/Saale, Osterburg, beide Sachsen-Anhalt) untersucht. Als Market fuer eine verkehrsbedingte Exposition dienten benzol, Toluol und o-, m-, p-Xylol (BTX) im Blut und Platin im Morgenurin der Kinder. Mittels Fragebogen wurden Angaben zum Ausmass der Verkehrsexposition und zu moeglichen Stoereinfluessen (Zahnersatz, Passivrauchen, Exposition gegenueber loesungsmittelhaltigen Haushaltsprodukten etc.) erfragt. Die Ergebnisse dieser Studie zeigen, dass Emissionen des Kfz-Verkehrs einen nachweisbaren Einfluss auf die interne BTX-Belastung von Kindern haben. Waehrend sich die interne Benzol-belastung im Wesentlichen durch die Aussenluftbelastung mit Benzol durch die Kfz-Verkehrsdichte charakterisieren laesst, die sich mangels interner Quellen in der Innenraumluft widerspiegelt, existieren fuer das Toluol und die Xylole weitere relevante Quellen in Innenraeumen, was sich dadurch zeigt, dass die Toluol- und Xylolkonzentration in der Innenraumluft die in der Aussenluft uebersteigt. Die Platinkonzentrationen im Urin der Kinder aus den beiden verkehrsbelasteten Arealen zeigten im Vergleich zu den Kindern aus den weniger verkehrsbelasteten Arealen eine Tendenz zu hoeheren Werten, die jedoch statistisch nicht signifikant war. Die Ergebnisse lassen deshalb keinen eindeutigen Schluss darueber zu, ob die Ursache in der Freisetzung von Platin aus Autoabgaskatalysatoren liegt. Schlagwoerter: BTX; Human-Biomonitoring; Kinder; Platin; Verkehrsbelastung (orig.)

  20. Benzene poisoning

    Science.gov (United States)

    ... based chemical that has a sweet smell. Benzene poisoning occurs when someone swallows, breathes in, or touches ... number will let you talk to experts in poisoning. They will give you further instructions. This is ...

  1. Preparation of toluenes specifically labelled with C-14

    International Nuclear Information System (INIS)

    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.)

  2. 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

    Scientific Electronic Library Online (English)

    Ramin, Ghorbani-Vaghei; Hojat, Veisi.

    Full Text Available Descreve-se a preparação fácil e rápida de bis-indolil, tris-indolil, di(bis-indolil), tri(bis-indolil) e tetra(bis-indolil) metanos a partir de indole com diferentes aldeídos e cetonas, sob diferentes condições reacionais, usando poly(N,N´-dicloro-N-etil-benzeno-1,3 -disulfonamida), [PCBS], e N,N,N [...] ´,N´-tetraclorobenzeno-1,3-disulfonamida, [TCBDA], como novos catalizadores. Abstract in english 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.

  3. Pallidol hexaacetate ethyl acetate monosolvate

    Directory of Open Access Journals (Sweden)

    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, C40H34O12·C4H8O2. The ethyl acetate molecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009. Acta Cryst. D65, 148–155]; 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?Å 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 [C—O(carboxy—C—C torsion angles = ?70.24?(14, ?114.43?(10 and ?72.54?(13°]. In the crystal, a three-dimensional architecture is sustained by C—H...O interactions which encompass channels in which the disordered ethyl acetate molecules reside.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  5. Process intensification for the ethyl lactate synthesis : integrated pervaporation reactor

    OpenAIRE

    Pereira, C.S.M.; Silva, V.M.T.M.; Pinho, Simão; A. E Rodrigues

    2011-01-01

    Ethyl lactate is an important organic ester, which is biodegradable, produced by renewable resources and can be used as food additive, perfumery, flavor chemicals, solvent and pharmaceutical preparations[1]. It is a green solvent and could replace a range of environment-damaging halogenated and toxic solvents (for example: Nmethylpyrrolidone, toluene)[2]. The conventional way to produce ethyl lactate is the esterification of lactic acid with ethanol in the presence of an acid cata...

  6. Knoevenagel condensation of aromatic aldehydes with ethyl 4-chloro-3-oxobutanoate in ionic liquids

    Scientific Electronic Library Online (English)

    Bruno R. S. de, Paula; Dávila S., Zampieri; Julio, Zukerman-Schpector; Edward R. T., Tiekink; José Augusto R., Rodrigues; Paulo J. S., Moran.

    2012-05-01

    Full Text Available Condensações de Knoevenagel de aldeídos aromáticos com 4-cloro-3-oxobutanoato de etila catalisadas por morfolina/ácido acético foram conduzidas em líquidos iônicos para fornecerem 2-cloroacetil-3-arilpropenoatos de etila em 44 a 84% de rendimentos após 0,5 a 2 h à temperatura ambiente (25-28 ºC). Es [...] tas condições representam um protocolo mais verde para a condensação de Knoevenagel do que aquelas realizadas com refluxo de benzeno e tolueno, utilizados como solventes. Aldeídos aromáticos contendo grupos arila, 4-clorofenila, 4-metoxifenila, 2-tiofuranila, 2-furanila, fenila e 3,4-metilenodioxifenila apresentaram razões diastereoméricas (E)/(Z) de 56/44 a 85/15. A estrutura do isômero-(E) do 2-cloroacetil-3-(3',4'-metilenodioxifenil)propenoato de etila foi determinada por difração de raio X, e uma metodologia inequívoca da análise estrutural-(E)/(Z) por RMN de 13C (ressonância magnética nuclear) é apresentada. Abstract in english Knoevenagel condensations of aromatic aldehydes with ethyl 4-chloro-3-oxobutanoate catalyzed by morpholine/acetic acid were carried out in ionic liquids to give ethyl 2-chloroacetyl-3-arylpropenoates in 44-84% yield after 0.5 to 2 h at room temperature (25-28 ºC). These conditions represent a greene [...] r protocol for the Knoevenagel condensation than those using refluxing benzene or toluene as solvent. Aromatic aldehydes having aryl groups 4-chlorophenyl, 4-methoxyphenyl, 2-thiofuranyl, 2-furanyl, phenyl and 3,4-methylenedioxyphenyl gave (E)/(Z) diastereomeric ratios of products from 56/44 to 85/15. The two isomers of each compound were separately isolated and characterized. The structure of the (E)-isomer of ethyl 2-chloroacetyl-3-(3',4' methylenedioxyphenyl)propenoate was determined by X-ray crystallography and an unequivocal methodology of (E)/(Z)-structural analysis by 13C NMR (nuclear magnetic resonance) is presented.

  7. Facts about Benzene

    Science.gov (United States)

    ... Public Health Matters What's New A - Z Index Facts About Benzene What benzene is Benzene is a ... information on evacuation during a chemical emergency, see “ Facts About Evacuation .” For more information on sheltering in ...

  8. CFD SIMULATIONS OF BENZENETOLUENE SYSTEM OVER SIEVE TRAY

    Directory of Open Access Journals (Sweden)

    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.

  9. N-Cyclohexyl-N-ethyl-4-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Zeeshan Haider

    2010-01-01

    Full Text Available The title compound, C15H23NO2S, contains cyclohexyl and ethyl substituents on the sulfonamide N atom and the cyclohexyl ring adopts a classic chair conformation. The dihedral angle between the benzene ring plane and the mean plane through the six atoms of the cyclohexyl ring is 59.92?(6°. In the crystal structure, C—H...O hydrogen bonds link molecules into sheets extending in the bc plane.

  10. 1-Ethyl-3-(2,4,6-trimethylphenylimidazolium tetrafluoroborate

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Transformation of microflora during degradation of gaseous toluene in a biofilter detected using PCR-DGGE.

    Science.gov (United States)

    Okunishi, Suguru; Morita, Yasutaka; Higuchi, Takashi; Maeda, Hiroto; Nishi, Katsuji

    2012-07-01

    A laboratory-scale biofiltration system, the rotatory-switching biofilter (RSB), was operated for 199 days using toluene as a model pollutant. The target gaseous pollutant for the biofiltration experiment was approximately 300 ppmv of toluene. Toluene removal efficiency (RE, %) was initially approximately 20% with a 247-ppmv concentration (0.9 g m(-3)) of toluene during the first 10 days. Although the RE decreased several times whenever nitrogen was consumed, it again reached almost 100% when the nitrogen source was in sufficient supply. Denaturing gradient gel electrophoresis (DGGE) analysis was employed to assess the transformation ofmicroflora during operation of the biofilter The results based on a 16S rRNA gene profile showed that the microbial community structure changed with operation time. Although the microflora changed during the initial period (before day 40), transformation of the bacterial component was hardly observed after day 51. Statistical analyses of the DGGE profiles indicated that the bacterial community was almost unaffected by the environmental factors, such as adding ozone, high-level nitrogen supply, increase of loading toluene, and the shutdown of the RSB. The DGGE profile using tmoA-like genes, which encode proteins belonging to the hydroxylase component mono-oxygenases involved in the initial attack of aerobic benzene, toluene, ethylbenzene, and xylene degradation, confirmed the existence of toluene-degrading bacteria. There were at least four kinds of toluene-degradable bacteria having tmoA-like genes up to day 36, which decreased to two species after day 40. Sequence analysis after DGGE profiling revealed that Burkholderia cepacia, Sphingobacterium multivorum, and Pseudomonas putida were present in the biofilter. Only Alicycliphilus denitrificans was present throughout the whole operation period. In the initial stage of operating the RSB, many types of bacteria may have tried to adapt to the conditions, and subsequently, only selected bacteria were able to grow and to degrade toluene. PMID:22866576

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

    KAUST Repository

    Sinha, Sourab

    2014-10-22

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

  14. Effects of the presence of ethylacetate or benzene on the densities and volumetric properties of mixture (styrene + N,N-dimethylformamide)

    International Nuclear Information System (INIS)

    Densities have been measured as a function of composition for a ternary-pseudobinary mixture of {(styrene + ethyl acetate or benzene) + (N,N-dimethylformamide + ethyl acetate or benzene)} by means of a vibrating-tube densimeter at atmospheric pressure and the temperature 298.15 K. The excess molar volumes VmE were calculated from the densities and correlated using the Redlich-Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behaviour of the components. The results show the third component, ethyl acetate or benzene, have a significant influence on the interaction between styrene and N,N-dimethylformamide

  15. A detailed kinetic modeling study of toluene oxidation in a premixed laminar flame

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Z; Pitz, W J; Fournet, R; Glaude, P; Battin-Leclerc, F

    2009-12-18

    An improved chemical kinetic model for the toluene oxidation based on experimental data obtained in a premixed laminar low-pressure flame with vacuum ultraviolet (VUV) photoionization and molecular beam mass spectrometry (MBMS) techniques has been proposed. The present mechanism consists of 273 species up to chrysene and 1740 reactions. The rate constants of reactions of toluene, decomposition, reaction with oxygen, ipso-additions and metatheses with abstraction of phenylic H-atom are updated; new pathways of C{sub 4} + C{sub 2} species giving benzene and fulvene are added. Based on the experimental observations, combustion intermediates such as fulvenallene, naphtol, methylnaphthalene, acenaphthylene, 2-ethynylnaphthalene, phenanthrene, anthracene, 1-methylphenanthrene, pyrene and chrysene are involved in the present mechanism. The final toluene model leads to an overall satisfactory agreement between the experimentally observed and predicted mole fraction profiles for the major products and most combustion intermediates. The toluene depletion is governed by metathese giving benzyl radicals, ipso-addition forming benzene and metatheses leading to C{sub 6}H{sub 4}CH{sub 3} radicals. A sensitivity analysis indicates that the unimolecular decomposition via the cleavage of a C-H bond has a strong inhibiting effect, while decomposition via C-C bond breaking, ipso-addition of H-atom to toluene, decomposition of benzyl radicals and reactions related to C{sub 6}H{sub 4}CH{sub 3} radicals have promoting effect for the consumption of toluene. Moreover, flow rate analysis is performed to illustrate the formation pathways of mono- and polycyclic aromatics.

  16. Benzene from Traffic : Fuel Content and Ambient Air Concentrations

    DEFF Research Database (Denmark)

    Palmgren, F.; Berkowicz, R.

    2000-01-01

    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 in petrol from 1998 and the increasing number of vehicles with catalysts will probably lead to compliance with this limit value

  17. Toluene stability Space Station Rankine power system

    Science.gov (United States)

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

    1987-01-01

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

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

    Directory of Open Access Journals (Sweden)

    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 C—C—C—C torsion angle of 88.3?(5°. The packing involves an intermolecular contact with a Br...Br distance of 3.491?(1?Å, having C—Br...Br angles of 173.4?(2 and 106.0?(2°. The crystal studied was an inversion twin.

  19. Determination of Bioactive Components of Ethyl Acetate Fraction of Punica granatum Rind Extract

    OpenAIRE

    Sangeetha, J.; K. Vijayalakshmi

    2011-01-01

    Punica granatum belongs to a Punicaceae family. The Punica granatum is valued as a powerful medicinal plant and used in folk medicines. Hence the present investigation was carried out to determine the possible chemical components from ethyl acetate fraction of Punica granatum rind extract by GC-MS Technique. This analysis revealed that ethyl acetate fraction of Punica granatum rind extract contain Pyrogallol (41.88%), 5-Hydroxymethylfurfural (14.10%), D-Allose (9.17%), 2-Methoxy-1, 4-Benzened...

  20. Benzene: questions and answers

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    This information booklet is intended to inform residents near natural gas dehydration facilities about benzene and its levels in the atmosphere. It was issued following the federal government's decision to place benzene on its Priority Substances List and to require industry to establish means for reducing benzene emissions from natural gas dehydrators and to inform residents about benzene emissions from glycol dehydration facilities. Accordingly, the booklet explains what benzene is (a colourless flammable liquid component of hydrocarbons) how it gets into the air (during gasoline refining, vehicle refueling and the production of steel and petrochemicals), the associated health hazards (a recognized carcinogen, causing an increased incidence of leukemia in concentrations of 100 parts per million), defines a glycol dehydrator (a facility built at or near some natural gas fields for the removal of water from the natural gas to prevent corrosion and freezing of pipelines), and enumerates the steps that are being taken to reduce benzene levels in the air (benzene levels in gasoline have been reduced, along with benzene emissions from petrochemical plants, refineries, steel plants and glycol dehydrators by 54 per cent to date; this will rise to 90 per cent by 2005). In addition to these actions, industry plans call for all existing glycol dehydrators within 750 metres of any permanent residence to be limited to benzene emissions of no more than three tonnes per year before 2001; new glycol dehydrators after that date will be expected to have benzene emissions reduced to the lowest level that can be practically achieved.

  1. Toluene degradation by non-thermal plasma combined with a ferroelectric catalyst.

    Science.gov (United States)

    Liang, Wen-Jun; Ma, Lin; Liu, Huan; Li, Jian

    2013-08-01

    Degradation of toluene in a gas by non-thermal plasma with a ferroelectric catalyst was studied at normal temperature and atmospheric pressure. Spontaneous polarization material (BaTiO3) and photocatalyst (TiO2) were added into plasma system simultively. Toluene degradation efficiency and specific energy density during the discharge process were investigated. Furthermore, byproducts and degradation mechanisms of toluene were also investigated. The toluene degradation efficiency increased when non-thermal plasma technology was combined with the catalyst. The toluene degradation efficiencies of the different catalysts tested were in the following order: BaTiO3/TiO2>BaTiO3>TiO2>no catalyst. A mass ratio of 2.38:1 was optimum for the BaTiO3 and TiO2 catalyst. The outlet gas was analyzed by gas chromatography and Fourier transform infrared spectroscopy, and the main compounds detected were CO2, H2O, O3 and benzene ring derivatives. PMID:23773445

  2. Soot precursor measurements in benzene and hexane diffusion flames

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Furuhata, T.; Amagai, K.; Arai, M. [Department of Mechanical System Engineering, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515 (Japan)

    2008-08-15

    To clarify the mechanism of soot formation in diffusion flames of liquid fuels, measurements of soot and its precursors were carried out. Sooting diffusion flames formed by a small pool combustion equipment system were used for this purpose. Benzene and hexane were used as typical aromatic and paraffin fuels. A laser-induced fluorescence (LIF) method was used to obtain spatial distributions of polycyclic aromatic hydrocarbons (PAHs), which are considered as soot particles. Spatial distributions of soot in test flames were measured by a laser-induced incandescence (LII) method. Soot diameter was estimated from the temporal change of LII intensity. A region of transition from PAHs to soot was defined from the results of LIF and LII. Flame temperatures, PAH species, and soot diameters in this transition region were investigated for both benzene and hexane flames. The results show that though the flame structures of benzene and hexane were different, the temperature in the PAHs-soot transition region of the benzene flame was similar to that of the hexane flame. Furthermore, the relationship between the PAH concentrations measured by gas chromatography in both flames and the PAH distributions obtained from LIF are discussed. It was found that PAHs with smaller molecular mass, such as benzene and toluene, remained in both the PAHs-soot transition and sooting regions, and it is thought that molecules heavier than pyrene are the leading candidates for soot precursor formation. (author)

  3. An overview of benzene metabolism.

    OpenAIRE

    Snyder, R; Hedli, C C

    1996-01-01

    Benzene toxicity involves both bone marrow depression and leukemogenesis caused by damage to multiple classes of hematopoietic cells and a variety of hematopoietic cell functions. Study of the relationship between the metabolism and toxicity of benzene indicates that several metabolites of benzene play significant roles in generating benzene toxicity. Benzene is metabolized, primarily in the liver, to a variety of hydroxylated and ring-opened products that are transported to the bone marrow w...

  4. Leukemia and Benzene

    OpenAIRE

    Robert Snyder

    2012-01-01

    Excessive exposure to benzene has been known for more than a century to damage the bone marrow resulting in decreases in the numbers of circulating blood cells, and ultimately, aplastic anemia. Of more recent vintage has been the appreciation that an alternative outcome of benzene exposure has been the development of one or more types of leukemia. While many investigators agree that the array of toxic metabolites, generated in the liver or in the bone marrow, can lead to traumatic bone marrow...

  5. Benzene Monitor System report

    International Nuclear Information System (INIS)

    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)

  6. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

    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 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 gesta...

  7. Biodegradation of toluene in a trickling filter

    OpenAIRE

    Peixoto, J.; M. Mota

    1998-01-01

    A trickling filter packed with PVC 16 mm Raschig rings was used to study the degradation of toluene in a polluted air stream, by means of a bacterial biofilm of Pseudomonas putida ATCC 17484. A polluted stream was simulated by blending air with a controlled amount of toluene. The mixing was accomplished in a special mixing chamber designed for that purpose. Induction of the enzymes of the toluene degradative pathway and adaptation of the inoculum were done in batch cultures with mini...

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

    Energy Technology Data Exchange (ETDEWEB)

    Kern, R.D.; Chen, H.; Qin, Z. [Univ. of New Orleans, LA (United States)

    1993-12-01

    The main focus of this program is to investigate the thermal decompositions of fuels that play an important role in the pre-particle soot formation process. It has been demonstrated that the condition of maximum soot yield is established when the reaction conditions of temperature and pressure are sufficient to establish a radical pool to support the production of polyaromatic hydrocarbon species and the subsequent formation of soot particles. However, elevated temperatures result in lower soot yields which are attributed to thermolyses of aromatic ring structures and result in the bell-shaped dependence of soot yield on temperature. The authors have selected several acyclic hydrocarbons to evaluate the chemical thermodynamic and kinetic effects attendant to benzene formation. To assess the thermal stability of the aromatic ring, the authors have studied the pyrolyses of benzene, toluene, ethylbenzene, chlorobenzene and pyridine. Time-of-flight mass spectrometry (TOF) is employed to analyze the reaction zone behind reflected shock waves. Reaction time histories of the reactants, products, and intermediates are constructed and mechanisms are formulated to model the experimental data. The TOF work is often performed with use of laser schlieren densitometry (LS) to measure density gradients resulting from the heats of various reactions involved in a particular pyrolytic system. The two techniques, TOF and LS, provide independent and complementary information about ring formation and ring rupture reactions.

  9. Índicesde refracción 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 / Índices derefração e densidade de misturas binárias de heptano com ciclo-hexano, benzenoe tolueno a 293.15, 298.15, 303.15 e 308.15 K

    Scientific Electronic Library Online (English)

    Marlon D., Martínez-Reina; Eliseo, Amado-González.

    2012-06-01

    Full Text Available Determinam-sedensidades e índices de refração de misturas binárias 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 índice de refração (??D) a partir dosdados experimentais e ajustados à uma equação polinomial [...] de Redlich-Kister deordem quatro. Abstract in spanish Semidieron densidades e índices de refracción 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 índice de refracción (??D) son calculados desdelos datos experimentales y ajustados con una ecuación 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.

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    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 2004–2006. 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 (20–50 pptv in 2004–2006. 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.

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

    Directory of Open Access Journals (Sweden)

    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 2004–2006. 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 (20–50 pptv in 2004–2006. 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.

  13. Observation of Replacement of Carbon in Benzene with Nitrogen in a Low-Temperature Plasma

    Science.gov (United States)

    Zhang, Zhiping; Gong, Xiaoyun; Zhang, Sichun; Yang, Haijun; Shi, Youmin; Yang, Chengdui; Zhang, Xinrong; Xiong, Xingchuang; Fang, Xiang; Ouyang, Zheng

    2013-12-01

    Selective activation of benzene has been mainly limited to the C-H activation. Simple replacement of one carbon in benzene with another atom remains unresolved due to the high dissociation energy. Herein, we demonstrate a direct breakage of the particularly strong C = C bond in benzene through ion-molecule reaction in a low-temperature plasma, in which one carbon atom was replaced by one atomic nitrogen with the formation of pyridine. The mechanism for the formation of pyridine from benzene has been proposed based on the extensive investigation with tandem mass spectrometry. The reaction pathway also works to other aromatics such as toluene and o-xylene. This finding provides a new avenue for selective conversion of aromatics into nitrogen-containing compounds.

  14. FIELD COMPARISON OF TWO KINDS OF CHARCOAL TUBES FOR SAMPLING AROMATIC HYDROCARBONS (TOLUENE & XYLENE) IN A PAINT FACTORY

    OpenAIRE

    P .Nassiri; F. Golbabai; A. Barzegar

    1996-01-01

    In order to evaluate the effectiveness of the Iranian made charcoal tubes in the field , 60 local made and 60 imported ones (SKC type) were randomly selected and placed side by side for sampling aromatic hydrocarbons (including Benzene, Toluene, Xylene) in workers breathing zone in a paint factory. The results indicated that there were no statistically significant differences between the mean concentrations of aromatic hydrocarbons measured in studied groups. The ratios of pressure drop to fl...

  15. Leukemia and benzene.

    Science.gov (United States)

    Snyder, Robert

    2012-08-01

    Excessive exposure to benzene has been known for more than a century to damage the bone marrow resulting in decreases in the numbers of circulating blood cells, and ultimately, aplastic anemia. Of more recent vintage has been the appreciation that an alternative outcome of benzene exposure has been the development of one or more types of leukemia. While many investigators agree that the array of toxic metabolites, generated in the liver or in the bone marrow, can lead to traumatic bone marrow injury, the more subtle mechanisms leading to leukemia have yet to be critically dissected. This problem appears to have more general interest because of the recognition that so-called "second cancer" that results from prior treatment with alkylating agents to yield tumor remissions, often results in a type of leukemia reminiscent of benzene-induced leukemia. Furthermore, there is a growing literature attempting to characterize the fine structure of the marrow and the identification of so called "niches" that house a variety of stem cells and other types of cells. Some of these "niches" may harbor cells capable of initiating leukemias. The control of stem cell differentiation and proliferation via both inter- and intra-cellular signaling will ultimately determine the fate of these transformed stem cells. The ability of these cells to avoid checkpoints that would prevent them from contributing to the leukemogenic response is an additional area for study. Much of the study of benzene-induced bone marrow damage has concentrated on determining which of the benzene metabolites lead to leukemogenesis. The emphasis now should be directed to understanding how benzene metabolites alter bone marrow cell biology. PMID:23066403

  16. The Fate of Benzene Oxide

    OpenAIRE

    Monks, Terrence J.; Butterworth, Michael; Lau, Serrine S.

    2009-01-01

    Metabolism is a prerequisite for the development of benzene-mediated myelotoxicity. Benzene is initially metabolized via cytochromes P450 (primarily CYP2E1 in liver) to benzene oxide, which subsequently gives rise to a number of secondary products. Benzene oxide equilibrates spontaneously with the corresponding oxepine valence tautomer, which can ring open to yield a reactive ?-?-unsaturated aldehyde, trans-trans-muconaldehyde (MCA). Further reduction or oxidation of MCA gives rise to either ...

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

    International Nuclear Information System (INIS)

    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

  18. Benzene and its Health Effects

    Directory of Open Access Journals (Sweden)

    Mustafa Tozun

    2008-12-01

    Full Text Available Benzene is an aromatic hydrocarbon, colorless, sweet-smelling liquid. It is an important industrial solvent, is used in the manufacture of plastics, detergents, pesticides, and other chemicals. Benzene is a carcinogen. Short-term and high level benzene exposure causes symptoms of the central nervous system. Long-term benzene exposure may affect to bone marrow and blood production. Additionally, genotoxic, immunological, and urogenital negative effects may occur with chronicle benzene exposure. [TAF Prev Med Bull 2008; 7(6.000: 541-546

  19. An overview of benzene metabolism.

    Science.gov (United States)

    Snyder, R; Hedli, C C

    1996-01-01

    Benzene toxicity involves both bone marrow depression and leukemogenesis caused by damage to multiple classes of hematopoietic cells and a variety of hematopoietic cell functions. Study of the relationship between the metabolism and toxicity of benzene indicates that several metabolites of benzene play significant roles in generating benzene toxicity. Benzene is metabolized, primarily in the liver, to a variety of hydroxylated and ring-opened products that are transported to the bone marrow where subsequent secondary metabolism occurs. Two potential mechanisms by which benzene metabolites may damage cellular macromolecules to induce toxicity include the covalent binding of reactive metabolites of benzene and the capacity of benzene metabolites to induce oxidative damage. Although the relative contributions of each of these mechanisms to toxicity remains unestablished, it is clear that different mechanisms contribute to the toxicities associated with different metabolites. As a corollary, it is unlikely that benzene toxicity can be described as the result of the interaction of a single metabolite with a single biological target. Continued investigation of the metabolism of benzene and its metabolites will allow us to determine the specific combination of metabolites as well as the biological target(s) involved in toxicity and will ultimately lead to our understanding of the relationship between the production of benzene metabolites and bone marrow toxicity. PMID:9118888

  20. Primary atmospheric oxidation mechanism for toluene.

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  3. 4-(Dimethyl­amino)benzaldehyde 4-ethyl­thio­semicarbazone

    OpenAIRE

    Salhin, Abdussalam; Razak, Norfarhah Abdul; I. A. Rahman

    2008-01-01

    The title thio­semicarbazone derivative, C12H18N4S, features intra­molecular N—H?N and C—H?S hydrogen bonds which generate S(5) ring motifs. The dihedral angle between the benzene ring and the thio­urea unit is 6.30?(6)° indicating planarity in the mol­ecule. Inter­molecular N—H?S hydrogen bonds generate dimers with an R 2 2(8) ring motif. The methyl group of the N-ethyl residue is disordered and was refined with site occupancies of 0.521?(5) and 0.479?(5)....

  4. Volatilization of benzene and eight alkyl-substituted benzene compounds from water

    Science.gov (United States)

    Rathbun, R.E.; Tai, D.Y.

    1988-01-01

    Predicting the fate of organic compounds in streams and rivers often requires knowledge of the volatilization characteristics of the compounds. The reference-substance concept, involving laboratory-determined ratios of the liquid-film coefficients for volatilization of the organic compounds to the liquid-film coefficient for oxygen absorption, is used to predict liquid-film coefficients for streams and rivers. In the absence of experimental data, two procedures have been used for estimating these liquid-film coefficient ratios. These procedures, based on the molecular-diffusion coefficient and on the molecular weight, have been widely used but never extensively evaluated. Liquid-film coefficients for the volatilization of benzene and eight alkyl-substituted benzene compounds (toluene through n-octylbenzene) from water were measured in a constant-temperature, stirred water bath. Liquid-film coefficients for oxygen absorption were measured simultaneously. A range of water mixing conditions was used with a water temperature of 298.2 K. The ratios of the liquid-film coefficients for volatilization to the liquid-film coefficient for oxygen absorption for all of the organic compounds were independent of mixing conditions in the water. Experimental ratios ranged from 0.606 for benzene to 0.357 for n-octylbenzene. The molecular-diffusion-coefficient procedure accurately predicted the ratios for ethylbenzene through n-pentylbenzene with a power dependence of 0.566 on the molecular-diffusion coefficient, in agreement with published values. Predicted ratios for benzene and toluene were slightly larger than the experimental ratios. These differences were attributed to possible interactions between the molecules of these compounds and the water molecules and to benzene-benzene interactions that form dimers. Because these interactions also are likely to occur in natural waters, it was concluded that the experimental ratios are more correct than the predicted ratios for application purposes in the reference-substance concept. Predicted ratios for n-hexylbenzene, n-heptylbenzene, and n-octylbenzene were larger than the experimental ratios. These differences were attributed to a sorption-desorption process between these compounds and the surfaces of the constant-temperature water bath. Other experimental problems associated with preparing water solutions of these slightly soluble compounds also may have contributed to the differences. Because these processes are not part of the true volatilization process, it was concluded that the predicted ratios for these three compounds are probably more correct than the experimental ratios for application purposes in the reference-substance concept. Any model of the fate of these compounds in streams and rivers would have to include terms accounting for sorption processes, however. The molecular-weight procedure accurately predicted the ratios for ethylbenzene through n-pentylbenzene, but only if the power dependence on the molecular weight was decreased from the commonly used -0.500 to -0.427. Deviations for the low- and high-molecular-weight compounds were similar to those observed for the molecular-diffusion-coefficient procedure.

  5. Benzene oxidation coupled to sulfate reduction

    Science.gov (United States)

    Lovley, D.R.; Coates, J.D.; Woodward, J.C.; Phillips, E.J.P.

    1995-01-01

    Highly reduced sediments from San Diego Bay, Calif., that were incubated under strictly anaerobic conditions metabolized benzene within 55 days when they were exposed initially to I ??M benzene. The rate of benzene metabolism increased as benzene was added back to the benzene-adapted sediments. When a [14C]benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as 14CO2. Molybdate, an inhibitor of sulfate reduction, inhibited benzene uptake and production of 14CO2 from [14C]benzene. Benzene metabolism stopped when the sediments became sulfate depleted, and benzene uptake resumed when sulfate was added again. The stoichiometry of benzene uptake and sulfate reduction was consistent with the hypothesis that sulfate was the principal electron acceptor for benzene oxidation. Isotope trapping experiments performed with [14C]benzene revealed that there was no production of such potential extracellular intermediates of benzene oxidation as phenol, benzoate, p-hydroxybenzoate, cyclohexane, catechol, and acetate. The results demonstrate that benzene can be oxidized in the absence of O2, with sulfate serving as the electron acceptor, and suggest that some sulfate reducers are capable of completely oxidizing benzene to carbon dioxide without the production of extracellular intermediates. Although anaerobic benzene oxidation coupled to chelated Fe(III) has been documented previously, the study reported here provides the first example of a natural sediment compound that can serve as an electron acceptor for anaerobic benzene oxidation.

  6. Stemofoline ethyl acetate solvate

    Directory of Open Access Journals (Sweden)

    Pitchaya Mungkornasawakul

    2009-08-01

    Full Text Available Crystals of the title compound, C22H29NO5·C4H8O2, {[systematic name: (2R,3R,5R,5aS,6R,8aR,9S-(5Z-5-[3-butyltetrahydro-6-methyl-2,5-methano-4,3,8a-[1]propanyl[3]ylidenefuro[3,2-f][1,4]oxazepin-7(5H-ylidene]-4-methoxy-3-methylfuran-2(5H-one ethyl acetate solvate} were isolated from the root extracts of Stemona aphylla (Stemonaceae. The structure closely resembles those of stemofoline derivatives which have previously been reported. Intermolecular contacts are observed between some C-bonded H atoms and nearby O atoms, perhaps indicating weak interactions which could influence the packing of species within the unit cell.

  7. Hematotoxicity and carcinogenicity of benzene

    Energy Technology Data Exchange (ETDEWEB)

    Aksoy, M. (Scientific and Technical Research Council of Turkey, Kocaeli (Turkey))

    1989-07-01

    The hematotoxicity of benzene exposure has been well known for a century. Benzene causes leukocytopenia, thrombocytopenia, pancytopenia, etc. The clinical and hematologic picture of aplastic anemia resulting from benzene exposure is not different from classical aplastic anemia; in some cases, mild bilirubinemia, changes in osmotic fragility, increase in lactic dehydrogenase and fecal urobilinogen, and occasionally some neurological abnormalities are found. Electromicroscopic findings in some cases of aplastic anemia with benzene exposure were similar to those observed by light microscopy. Benzene hepatitis-aplastic anemia syndrome was observed in a technician with benzene exposure. Ten months after occurrence of hepatitis B, a severe aplastic anemia developed. The first epidemiologic study proving the leukemogenicity of benzene was performed between 1967 and 1973 to 1974 among shoe workers in Istanbul. The incidence of leukemia was 13.59 per 100,000, which is a significant increase over that of leukemia in the general population. Following the prohibition and discontinuation of the use of benzene in Istanbul, there was a striking decrease in the number of leukemic shoe workers in Istanbul. In 23.7% of the series, consisting of 59 leukemic patients with benzene exposure, there was a preceding pancytopenic period. Furthermore, a familial connection was found in 10.2% of them. The 89.8% of the series showed the findings of acute leukemia. The possible factors that may determine the types of leukemia in benzene toxicity are discussed. The possible role of benzene exposure is presented in the development of malignant lymphoma, multiple myeloma, and lung cancer.

  8. Human response to varying concentrations of toluene

    DEFF Research Database (Denmark)

    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 exercised in three 15-min periods with a load of 50 to 100 W. Exposure to toluene caused significant (P less than 0.05) complaints about poor air quality, altered temperature and noise perception, increase...

  9. Menstrual function in workers exposed to toluene.

    OpenAIRE

    Ng, T. P.; Foo, S C; Yoong, T

    1992-01-01

    Rates of menstrual disorders were studied in 231 female production workers with high exposure to toluene (mean 88 (range 50-150 ppm) in a factory manufacturing audio speakers and compared with a control group of 58 female production workers in other departments in the same factory who had little or no exposure to toluene (0-25 ppm). An external community control group of 187 working class women under routine care at public maternal and child health centres were also studied. Detailed menstrua...

  10. Catalytic oxidation of CO, hydrocarbons and ethyl acetate over perovskite-type complex oxides

    International Nuclear Information System (INIS)

    The catalytic activity of M1M2O3 perovskite-type complex oxides (M1 = La, Y, Nd, Yb, M2 = Co, Mn, Ni) was investigated in the oxidation of CO, propylene, benzene, ethylbenzene, o-xylol and ethyl acetate. Co-containing catalysts were more active than Mn-containing ones in the oxidation. The relationship between the catalytic and adsorption properties was established. 8 refs., 5 figs

  11. Experimental study of the density and viscosity of 1-ethyl-3-methylimidazolium ethyl sulfate

    International Nuclear Information System (INIS)

    Highlights: ? Density of the ionic liquid [EMIM][EtSO4]. ? Viscosity of the ionic liquid [EMIM][EtSO4]. ? Thermodynamic properties of ionic liquid [EMIM][EtSO4]. ? Equation of state of ionic liquid [EMIM][EtSO4]. - Abstract: Density and viscosity of 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO4] have been measured over the temperature range from (283.15 to 413.15) K and at pressures up to 140 MPa and in the temperature range from (283.15 to 373.15) K at 0.1 MPa, respectively. The expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be (0.01 to 0.08)%, 0.1%, 15 mK, and 0.35%, respectively. The measurements were carried out with an Anton–Paar DMA HPM vibration-tube densimeter and a fully automated SVM 3000 Anton–Paar rotational Stabinger viscometer. The vibration-tube densimeter was calibrated using various reference fluids, double-distilled water, methanol, toluene, and aqueous NaCl solutions. An empiric equation of state for [EMIM][EtSO4] has been developed using the measured (p, ?, T) data. This equation was used to calculate the various thermodynamic properties of the IL and for compare with measured properties (speed of sound and enthalpy). Theoretically based Arrhenius–Andrade and Vogel–Tamman–Fulcher type equations were use to describe of the temperature dependence of measured viscosities for [EMIM][EtSO4]. All measured properties were detailed compared with the reported data by other author.

  12. Toluene Induces Depression-Like Behaviors in Adult Mice

    OpenAIRE

    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 ...

  13. FIELD COMPARISON OF TWO KINDS OF CHARCOAL TUBES FOR SAMPLING AROMATIC HYDROCARBONS (TOLUENE & XYLENE IN A PAINT FACTORY

    Directory of Open Access Journals (Sweden)

    P .Nassiri; F. Golbabai; A. Barzegar

    1996-08-01

    Full Text Available In order to evaluate the effectiveness of the Iranian made charcoal tubes in the field , 60 local made and 60 imported ones (SKC type were randomly selected and placed side by side for sampling aromatic hydrocarbons (including Benzene, Toluene, Xylene in workers breathing zone in a paint factory. The results indicated that there were no statistically significant differences between the mean concentrations of aromatic hydrocarbons measured in studied groups. The ratios of pressure drop to flow rate of Iranian made tubes were statistically higher than the SKC ones (P<0.0l.

  14. Butyl acetate replaces toluene to remove phenol from water

    Energy Technology Data Exchange (ETDEWEB)

    Hodel, A.E.

    1993-03-01

    Plastics Engineering Co. manufactures phenol formaldehyde resins and molding compounds at a plant in Sheboygan, WI. Process water from the plant, containing 7% phenol and 1% methanol, requires treatment prior to discharge to the sewer. Toluene was used as a solvent in a countercurrent liquid-liquid extraction column. A vacuum distillation of the extract separated the phenol and toluene. The raffinate (1% methanol, 98% water and 1% toluene) was stripped to recover the toluene and remove methanol from the bottoms prior to discharge. Methanol was not recovered. Disposal costs for the waste methanol (with about 10% toluene as an azeotrope) were high.

  15. Volume reduction and toluene recuperation from liquid scintillation waste

    International Nuclear Information System (INIS)

    This paper describes the experimental work undertaken to evaluate the recuperation of the liquid scintillator by NaOH treatment and also a distillation process to recovery only the toluene. Recovered toluene was compared with scintillation grade toluene in terms of efficiency and background counts the IPEN - CNEN/SP laboratories as well in a radioimmunoassay laboratory. Both of them certified the quality, of the recovered toluene for radioimmunoassay. The volume reduction attained decreases significantly the costs of treatment for the remaing wastes beyond the profit of the toluene recovered. All procedures including equipment drawing and results are reported. (Author)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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 (? = 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

  18. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    Directory of Open Access Journals (Sweden)

    OLIVIA ANCA RUSU

    2011-03-01

    Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 ?g/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.

  19. Inquinamento outdoor - indoor da toluene e xileni

    Directory of Open Access Journals (Sweden)

    U. Moscato

    2003-05-01

    Full Text Available

    Obiettivi: il toluene e lo xilene (TX rappresentano alcuni degli inquinanti aromatici più diffusi perché ubiquitari. Poiché la loro contaminazione può determinare effetti tossico-nocivi, lo scopo di questo studio è stato quello di valutare la concentrazione dei TX in alcuni distretti di Roma, al fine di accertare l’esposizione della popolazione e promuovere il “Risk Management” dell’inquinamento da idrocarburi in ambiente.

    Metodi: il campionamento dei TX è stato realizzato in tre fasi, utilizzando campionatori passivi a simmetria radiale, disposti in circa 150 siti, per un tempo di esposizione di due giorni. I campioni sono stati desorbiti in solvente ed analizzati in Gas-Cromatografia-FID. I dati sono stati elaborati attraverso la statistica descrittiva ed analisi del coefficiente di correlazione tra i livelli di TX outdoor- indoor. È stata inoltre condotta un’analisi di regressione lineare multipla (metodo backward elimination con i valori di TX indoor come variabili dipendenti e come covariate i valori di TX outdoor, la velocità dell’aria, la temperatura, l’umidità relativa e la presenza di fumatori. Risultati: i valori medi delle concentrazioni di toluene (outdoor 1,43–461,6 mg/m3; indoor 16,7- 185,3 mg/m3 e dello xilene (outdoor 1,1–72,2 mg/m3; indoor 14,8-320,2 mg/m3 indicano un coefficiente di correlazione di 0.637 (primo periodo e 0.683 (terzo periodo di misurazione fra valori di toluene outdoor-indoor mentre, rispettivamente, di 0.928 e 0.955 per lo xilene, con elevatissimi livelli di significatività statistica per ambedue (p ‹ 0.0001. L’analisi multivariata mostra una stretta relazione tra i valori outdoor-indoor dei TX. Mentre i livelli di toluene indoor sono circa un quinto dei valori registrati all’esterno, i livelli di xilene indoor, altresì, sono da due a quattro volte maggiori dei valori outdoor.

    Conclusioni: i risultati suggeriscono che l’esposizione a toluene e xilene non dovrebbe essere sottostimata in quanto responsabile di effetti prevalentemente cronici sulla popolazione esposta, in particolare negli ambienti confinati.

  20. Phase II metabolism of benzene.

    Science.gov (United States)

    Schrenk, D; Orzechowski, A; Schwarz, L R; Snyder, R; Burchell, B; Ingelman-Sundberg, M; Bock, K W

    1996-01-01

    The hepatic metabolism of benzene is thought to be a prerequisite for its bony marrow toxicity. However, the complete pattern of benzene metabolites formed in the liver and their role in bone marrow toxicity are not fully understood. Therefore, benzene metabolism was studied in isolated rodent hepatocytes. Rat hepatocytes released benzene-1,2-dihydrodiol, hydroquinone (HQ), catechol (CT), phenol (PH), trans-trans-muconic acid, and a number of phase II metabolites such as PH sulfate and PH glucuronide. Pretreatment of animals with 3-methylcholantrene (3-MC) markedly increased PH glucuronide formation while PH sulfate formation was decreased. Likewise, V79 cells transfected with the 3-MC-inducible rat UGT1.6 cDNA showed a considerable rate of PH and HQ glucuronidation. In addition to inducing glucuronidation of phenols, 3-MC treatment (reported to protect rats from the myelotoxicity of benzene) resulted in a decrease of hepatic CYP2E1. In contrast, pretreatment of rats with the CYP2E1-inducer isopropanol strongly enhanced benzene metabolism and the formation of phenolic metabolites. Mouse hepatocytes formed much higher amounts of HQ than rat hepatocytes and considerable amounts of 1,2,4-trihydroxybenzene (THB) sulfate and HQ sulfate. In conclusion, the protective effect of 3-MC in rats is probably due to a shift from the labile PH sulfate to the more stable PH glucuronide, and to a decrease in hepatic CYP2E1. The higher susceptibility of mice toward benzene may be related to the high rate of formation of the myelotoxic metabolite HQ and the semistable phase II metabolites HQ sulfate and THB sulfate. Images Figure 4. PMID:9118891

  1. Ultraselective and sensitive detection of xylene and toluene for monitoring indoor air pollution using Cr-doped NiO hierarchical nanostructures

    Science.gov (United States)

    Kim, Hyo-Joong; Yoon, Ji-Wook; Choi, Kwon-Il; Jang, Ho Won; Umar, Ahmad; Lee, Jong-Heun

    2013-07-01

    Ultraselective and sensitive detection of xylene and toluene with minimum interferences of other indoor air pollutants such as benzene, ethanol, and formaldehyde is achieved using NiO hierarchical nanostructures doped with Cr. Pure and 1.15-2.56 at% Cr-doped NiO flower-like hierarchical nanostructures assembled from nanosheets are prepared by a simple solvothermal reaction and their gas sensing characteristics toward o-xylene and toluene gases are investigated. The 1.15 at% Cr-doped NiO hierarchical nanostructures show high responses to 5 ppm of o-xylene and toluene (ratio of resistance to gas and air = 11.61 and 7.81, respectively) and negligible cross-responses to 5 ppm of benzene, formaldehyde, ethanol, hydrogen, and carbon monoxide. However, pure NiO nanostructures show low responses to 5 ppm of o-xylene and toluene (ratio of resistance to gas and air = 2.01 and 1.14, respectively) and no selectivity toward any specific gas is observed. Significant enhancement of the response and selectivity to o-xylene and toluene is attributed to the decrease in the hole concentration in NiO and the catalytic oxidation of methyl groups by Cr doping.Ultraselective and sensitive detection of xylene and toluene with minimum interferences of other indoor air pollutants such as benzene, ethanol, and formaldehyde is achieved using NiO hierarchical nanostructures doped with Cr. Pure and 1.15-2.56 at% Cr-doped NiO flower-like hierarchical nanostructures assembled from nanosheets are prepared by a simple solvothermal reaction and their gas sensing characteristics toward o-xylene and toluene gases are investigated. The 1.15 at% Cr-doped NiO hierarchical nanostructures show high responses to 5 ppm of o-xylene and toluene (ratio of resistance to gas and air = 11.61 and 7.81, respectively) and negligible cross-responses to 5 ppm of benzene, formaldehyde, ethanol, hydrogen, and carbon monoxide. However, pure NiO nanostructures show low responses to 5 ppm of o-xylene and toluene (ratio of resistance to gas and air = 2.01 and 1.14, respectively) and no selectivity toward any specific gas is observed. Significant enhancement of the response and selectivity to o-xylene and toluene is attributed to the decrease in the hole concentration in NiO and the catalytic oxidation of methyl groups by Cr doping. Electronic supplementary information (ESI) available: X-ray diffraction patterns and SEM images of pure and Cr-doped Ni precursors; XPS spectra, pore size distribution, gas response, sensor resistance in air, gas selectivity of pure and Cr-doped NiO hierarchical nanostructures. See DOI: 10.1039/c3nr01281f

  2. Diffusion and adsorption of benzene in Regina clay

    International Nuclear Information System (INIS)

    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

  3. Ethyl 2-[1-(3-methylbutyl-4-phenyl-1H-1,2,3-triazol-5-yl]-2-oxoacetate

    Directory of Open Access Journals (Sweden)

    Muhammad Hafeez

    2013-12-01

    Full Text Available In the title compound, C17H21N3O3, the non-planar (r.m.s. deviation = 0.212?Å ethyl (oxoacetate group is oriented towards the phenyl substituent. The triazole and benzene rings are twisted with respect to each other, making a dihedral angle of 41.69?(6°. In the crystal, molecules are arranged into centrosymmetric R22(10 dimers via pairs of C—H...O interactions involving the ethyl (oxoacetate groups. In addition, the triazole rings show ?–? stacking interactions, with their centroids at a distance of 3.745?(2?Å.

  4. Antipyrine clearance during experimental and occupational exposure to toluene

    DEFF Research Database (Denmark)

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

    1983-01-01

    Exposure to toluene vapour enhances hepatic microsomal enzyme function in animals as assessed by the metabolism of the test drug antipyrine. Thirty six printing trade workers with long term occupational exposure to a mixture of organic solvents and 39 matched controls were randomly allocated 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 unde...

  5. 21 CFR 172.868 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ...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...

  6. 21 CFR 573.420 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in...

  7. ESTUDIO DEL EQUILIBRIO LÍQUIDO-LÍQUIDO DE BENCENO + (HEXANO, HEPTANO Y CICLOHEXANO) CON EL LÍQUIDO IÓNICO 1-ETIL-3-METILIMIDAZOLIO ETILSULFATO A 308,15 K / STUDY 0F LIQUID-LIQUID EQUILIBRIIM 0F BENZENE + (HEXAXE, HEPTME A\\D CYCLOHEXAXE) WITH THE IOMC LIQUID 1-ETHYL-3-METHYLIMIDAZ0LIIM ETHYLSULFATE AT 308.15 K / ESTUDO DO EQUILÍBRIO LÍQUIDO-LÍQUIDO DE BENZENO + (HEXANO, HEPTANO E CICLO-HEXANO) COM O LÍQUIDO IÔNICO 1-ETIL-3-METILIMIDAZOLIO ETILSULFATO A 308,15 K

    Scientific Electronic Library Online (English)

    Marlon, Martínez Reina; Eliseo, Amado González; Yonny Mauricio, Muñoz Muñoz.

    2012-01-01

    Full Text Available O equilíbrio líquido-líquido (ELL) de los sistemas ternários benzeno + (hexa-no, heptano e ciclo-hexano) com o líquido iônico 1-etil-3-metilimidazólio etilsulfato (EMIM-EtS0(4)) com 308,15 K, seletividade (S) e o coeficiente de distribuição (?) são calculados a partir dos dados experimentais. Ela de [...] termina a capacidade de líquido iônico como solvente para a separação de aromático a partir de suas misturas com hidrocar-bonetos alifáticos. A região de imiscibilidade aumentou na seguinte ordem: ciclo-hexano Abstract in spanish Se determinó el equilibrio líquido-líquido (ELL) de los sistemas ternarios benceno + (hexano, heptano y ciclohexano) con el líquido iónico 1-etil-3-metilimidazolio etilsulfato (EMIM-EtSO4) a 308,15 K; la selectividad (S) y el coeficiente de distribución (?) se calcularon desde los datos experimental [...] es que se utilizaron para determinar la capacidad del líquido iónico como solvente para la separación del aromático desde sus mezclas con hidrocarburos alifáticos. La región de inmiscibilidad aumentó en el siguiente orden: ciclohexano Abstract in english The equilibrium liquid-liquid (ELL) of ternary systems benzene + (hexane, heptane and cyclohexane) with the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate (EMIM-EtS0(4)) at 308.15 K, selectivity (S) and the distribution coefficient (?) are calculated from experimental data. The ability of ion [...] ic liquid as solvent for separation of the aromatic from their mixtures with ali-phatic hydrocarbons is analyzed. The region of immiscibility increased in the following order: cyclohexane

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. The preparation of alkyl benzene sulphonate, 14C-labelled in the benzene ring

    International Nuclear Information System (INIS)

    The paper describes the preparation of sodium alkyl sulphonate 14C-labelled in the benzene ring. The composition of the resultant product largely corresponded to that of a technical alkyl benzene sulphonate. It was obtained by sulphonation of alkyl benzene which, in turn, had been made by reacting 14C-labelled benzene with a technical olefin fraction. (orig.)

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

    International Nuclear Information System (INIS)

    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

  11. Benzene-templated hydrothermal synthesis of metal-organic frameworks with selective sorption properties.

    Science.gov (United States)

    Choi, Eun-Young; Park, Kyungsoo; Yang, Cheol-Min; Kim, Hyejin; Son, Jung-Ho; Lee, Soon W; Lee, Young Hee; Min, Dongwon; Kwon, Young-Uk

    2004-10-25

    In this paper, we report two metal-organic frameworks [Co3(ndc)3(bipyen)(1.5)]H2O (1) and [Co2(ndc)2bipyen)]C6H6.H2O (2) (bipyen=trans-1,2-bis(4-pyridyl)ethylene, H2ndc=2,6-naphthalenedicarboxylic acid). These compounds were both synthesized from identical hydrothermal reaction conditions except that benzene was added to the reaction for 2. Crystal structures show that the two compounds have triply interpenetrated three-dimensional frameworks and these frameworks have the same primary structure of a two-dimensional network of interconnected [Co2(O2CR)(4/2)] (R=naphthalene group) paddle-wheels and bridging bipyen ligands. Both compounds have guest water molecules and, in addition, 2 has guest benzene molecules. Structural transformations of the host accompanied guest removal, which can be monitored by powder X-ray diffraction. N2 adsorption data of 2 show that there are two different types of pores corresponding to the benzene and water pores. Upon exposure to vapors of several organic molecules, the heat-treated sample of 2 adsorbs benzene and cyclohexene, but does not adsorb toluene, (o-, m-, and p-)xylenes, cycloheptatriene, or cyclohexane. PMID:15457511

  12. PERFORMANCE OF TRICKLE BED BIOFILTERS UNDER HIGH TOLUENE LOADING

    Science.gov (United States)

    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...

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 ?2,1 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

  15. Ethyl 2-(5-bromo-3-ethylsulfinyl-1-benzofuran-2-ylacetate

    Directory of Open Access Journals (Sweden)

    Hong Dae Choi

    2009-04-01

    Full Text Available The title compound, C14H15BrO4S, was prepared by the oxidation of ethyl 2-(5-bromo-3-ethylsulfanyl-1-benzofuran-2-ylacetate with 3-chloroperoxybenzoic acid. The crystal structure is stabilized by aromatic ?–? interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.814?(9?Å], and possibly by weak C—H...? interactions. In addition, the crystal structure exhibits three intermolecular C—H...O non-classical hydrogen bonds. The ethyl group bonded to carboxylate O atom is disordered over two positions, with refined site-occupancy factors of 0.686?(18 and 0.314?(18.

  16. Slow Neutron Scattering by Benzene

    International Nuclear Information System (INIS)

    We have calculated the scattering of slow neutrons by the benzene molecule. The calculations are carried out within the framework of the time dependent formalism of Zemach and Glauber. Detailed account is taken of the effects of the molecular vibrations on the neutron scattering. Among the results explicitly calculated are the slow neutron total scattering cross-section as a function of energy and the energy angular distribution of singly scattered sections. (author)

  17. 21 CFR 184.1293 - Ethyl alcohol.

    Science.gov (United States)

    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....

  18. Bacterial dehalorespiration with chlorinated benzenes.

    Science.gov (United States)

    Adrian, L; Szewzyk, U; Wecke, J; Görisch, H

    2000-11-30

    Chlorobenzenes are toxic, highly persistent and ubiquitously distributed environmental contaminants that accumulate in the food chain. The only known microbial transformation of 1,2,3,5-tetrachlorobenzene (TeCB) and higher chlorinated benzenes is the reductive dechlorination to lower chlorinated benzenes under anaerobic conditions observed with mixed bacterial cultures. The lower chlorinated benzenes can subsequently be mineralized by aerobic bacteria. Here we describe the isolation of the oxygen-sensitive strain CBDB1, a pure culture capable of reductive dechlorination of chlorobenzenes. Strain CBDB1 is a highly specialized bacterium that stoichiometrically dechlorinates 1,2,3-trichlorobenzene (TCB), 1,2,4-TCB, 1,2,3,4-TeCB, 1,2,3,5-TeCB and 1,2,4,5-TeCB to dichlorobenzenes or 1,3,5-TCB. The presence of chlorobenzene as an electron acceptor and hydrogen as an electron donor is essential for growth, and indicates that strain CBDB1 meets its energy needs by a dehalorespiratory process. According to their 16S rRNA gene sequences, strain CBDB1, Dehalococcoides ethenogenes and several uncultivated bacteria form a new bacterial cluster, of which strain CBDB1 is the first, so far, to thrive on a purely synthetic medium. PMID:11117744

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

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Arvin, E.

    1997-01-01

    A lab-scale trickling filter for treatment of toluene-containing waste gas was investigated. The filter performance was investigated for various loads of toluene. Two levels of the gas flow were examined, 322 m d(-1) and 707 m d(-1). The gas inlet concentrations were varied in the range from 0.6 to 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 report...

  20. Muonium radicals in benzene-styrene mixtures

    International Nuclear Information System (INIS)

    Muonium radicals were observed through their ?+SR precession frequencies in high transverse magnetic fields in pure benzene, pure styrene and their mixtures, all as liquids at room temperature. In benzene-styrene mixtures, the radicals obtained in each pure liquid are both present, so no slow (10-9-10-5 s) intermolecular exchange occurs; but strong selectivity was found with the formation of the radical from styrene being about eight-times more probable than the radical from benzene. (Auth.)

  1. Benzene and leukemia: an epidemiologic risk assessment.

    OpenAIRE

    Rinsky, R A

    1989-01-01

    To assess quantitatively the association between benzene and leukemia, we evaluated the rate of mortality experienced by a cohort occupationally exposed to benzene. Using data from historical air sampling surveys, we estimated the daily benzene exposure for each member of the cohort. The expected number of leukemia deaths was calculated and compared to the actual number of leukemia deaths that occurred. The overall standardized mortality ratio (SMR) for leukemia was 337. Person-years at risk ...

  2. (Z)-3-[1-(4-Methoxy­anilino)ethyl­idene]-4,5-dihydro­furan-2(3H)-one

    OpenAIRE

    Zhang, Li-ping; Ni, Cai-Hua; ZHANG, ZHAN-HUI

    2008-01-01

    In the title compound, C13H15NO3, the dihydro­furan­one ring is planar to within 0.012?(4)?Å and it forms a dihedral angle of 42.8?(2)° with the benzene ring. The amino­ethyl­idene group is coplanar with the dihydro­furan­one ring. The meth­oxy group is slightly twisted away from the benzene ring. An intra­molecular N—H?O hydrogen bond, generating an S(6) ring, is observed. In the crystal structure, the mol­ecules exist as C—H?O hydrogen-bonded dimers.

  3. Purification of benzene by extractive rectification

    Energy Technology Data Exchange (ETDEWEB)

    Smoroda, A.I.; Ovsii, A.N.; Kashaba, I.F.; Belitskii, A.N.; Beizer, V.N.; Iliev, V.V.; Pirozhkov, G.P.

    1978-01-01

    Benzene is a very important product, affecting the development of the organic synthesis industry, especially in the production of plastics and synthetic fibers. As a result, the production of benzene is constantly increasing. There is a simultaneous increase in the demands made on its quality. The results from removal of saturated hydrocarbon impurities from benzene by extractive rectification under industrial conditions at the Yasinovka Coke Works are given. The extractive rectification unit was shown to be practical and efficient in operation. The resulting benzene meets the present and expected user requirements.

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

    Czech Academy of Sciences Publication Activity Database

    Naseem Akhtar, M.; Tukur, N. M.; Al-Yassir, N.; Al-Khattaf, S.; ?ejka, Ji?í

    2010-01-01

    Ro?. 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

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

    Indian Academy of Sciences (India)

    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.

  6. Interactions between Asphaltenes and Water in Solutions in Toluene

    DEFF Research Database (Denmark)

    Khvostichenko, Daria; Andersen, Simon Ivar

    2008-01-01

    Binding of water by asphaltenes dissolved in toluene was investigated for two asphaltene samples, OMV1 and OMV2, from the same reservoir deposit. Solubility of water in asphaltene solutions in toluene was found to increase with an increasing asphaltene concentration, indicative of solubilization of water by asphaltenes. Fourier transform infrared (FTIR) spectroscopy of stretching modes of OH groups in the region of 3800-3100 cm(-1) was used to obtain insight into the state of water in water-unsa...

  7. Risk of spontaneous abortion in workers exposed to toluene.

    OpenAIRE

    Ng, T. P.; Foo, S. C.; Yoong, T

    1992-01-01

    Rates of spontaneous abortions were determined using a reproductive questionnaire administered by personal interview to 55 married women with 105 pregnancies. They were employed in an audio speaker factory and were exposed to high concentrations of toluene (mean 88, range 50-150 ppm). These rates of spontaneous abortion were compared with those among 31 women (68 pregnancies) who worked in other departments in the same factory and had little or no exposure to toluene (0-25 ppm), as well as wi...

  8. Study of gaseous benzene effects upon A549 lung epithelial cells using a novel exposure system.

    Science.gov (United States)

    Mascelloni, Massimiliano; Delgado-Saborit, Juana Maria; Hodges, Nikolas J; Harrison, Roy M

    2015-08-19

    Volatile organic compounds (VOCs) are ubiquitous pollutants known to be present in both indoor and outdoor air arising from various sources. Indoor exposure has increasingly become a major cause of concern due to the effects that such pollutants can have on health. Benzene, along with toluene, is one of the main components of the VOC mixture and is a known carcinogen due to its genotoxic effects. The aim of this study was to test the feasibility of an in vitro model to study the short-term effects of exposure of lung cells to airborne benzene. We studied the effects of exposure on DNA and the production of reactive oxygen species (ROS) in A549 cells, exposed to various concentrations of benzene (0.03; 0.1; 0.3 ppm) in gaseous form using a custom designed cell exposure chamber. Results showed a concentration-dependent increase of DNA breaks and an increase of ROS production, confirming the feasibility of the experimental procedure and validating the model for further in vitro studies of exposure to other VOCs. PMID:26022717

  9. Toluene mediated oxidative stress and granulo-monocytopoiesis

    Directory of Open Access Journals (Sweden)

    Boži? Tatjana P.

    2003-01-01

    Full Text Available 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 erythrocyte malondialdehyde (MDA, and hematological indices from peripheral blood and bone marrow. The biochemical acute phase response was manifested by an elevated Cp concentration in all experimental animals. The markedly enhanced MDA concentration and statistically significant decrease in albumin level in toluene treated rats, indicated damage, to blood vessel endothelia. Alterations of leukocytes of peripheral blood and bone marrow (BM granulocytic-monocytic progenitor cells were typical of an inflammatory response, with stimulation of granulo-monocytopoiesis. Therefore, it can be assumed that both toluene and propylene glycol mediated sterile peritonitis and oxidative stress injury, with changes intensified by toluene action.

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

    International Nuclear Information System (INIS)

    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)

  11. Mechanistic considerations in benzene physiological model development

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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.

  13. Diffusion of Benzene and Alkylbenzenes in n-Alkanes.

    Science.gov (United States)

    Kowert, Bruce A; Register, Paul M

    2015-10-01

    The translational diffusion constants, D, of benzene and a series of alkylbenzenes have been determined in four n-alkanes at room temperature using capillary flow techniques. The alkylbenzenes are toluene, ethylbenzene, 1-phenylpropane, 1-phenylpentane, 1-phenyloctane, 1-phenylundecane, 1-phenyltetradecane, and 1-phenylheptadecane. The n-alkanes are n-nonane, n-decane, n-dodecane, and n-pentadecane. Ratios of the solutes' D values are independent of solvent and in general agreement with the predictions of diffusion models for cylinders and lollipops. For the latter, an alkylbenzene's phenyl ring is the lollipop's candy; the alkyl chain is its handle. A model that considers the solutes to be spheres with volumes determined by the van der Waals increments of their constituent atoms is not in agreement with experiment. The diffusion constants of 1-alkene and n-alkane solutes in n-alkane solvents also are compared with the cylinder model; reasonably good agreement is found. The n-alkanes are relatively extended, and this appears to be the case for the alkyl chains of the 1-alkenes and alkylbenzenes as well. PMID:26417941

  14. Synthesis, spectroscopic, thermal and antimicrobial studies of toluene-3,4-dithiolatoarsenic(III) derivatives with some oxygen and sulphur donor ligands

    Science.gov (United States)

    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 SC6H3(CH3)SAsR {where R = OOCC6H5, SOCC6H5, OOCCH3, SOCCH3, OC6H5, SC6H5, OOCC6H4(OH), SCH2COOH} and SC6H3(CH3)SAsOOC-COOAsS(CH3)C6H3S. 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 (1H and 13C), 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.

  15. Cascade regulation of the toluene-3-monooxygenase operon (tbuA1UBVA2C) of Burkholderia pickettii PKO1: role of the tbuA1 promoter (PtbuA1) in the expression of its cognate activator, TbuT.

    Science.gov (United States)

    Byrne, A M; Olsen, R H

    1996-11-01

    Burkholderia pickettii PKO1 metabolizes toluene and benzene via a chromosomally encoded toluene-3-monooxygenase pathway. Expression of the toluene-3-monooxygenase operon (tbuA1UBVA2C) is activated by the regulator, TbuT, in the presence of toluene. We have identified the TbuT coding region downstream of the toluene-3-monooxygenase structural genes by nucleotide sequence analysis and have shown that although TbuT is similar to XylR and DmpR, two members of the NtrC family of transcriptional activators which control toluene-xylene and (methyl)phenol catabolism, respectively, it is significantly different in the domain associated with effector specificity. Using a tbuA1-lacZ fusion reporter system, we determined that TbuT is activated not only by aromatic effectors but also the chlorinated aliphatic hydrocarbon trichloroethylene. Expression of tbuT and that of the tbuA1UBVA2C operon were found to be linked by readthrough transcription of tbuT from the toluene-3-monooxygenase promoter. As a result, transcription of tbuT is low when the toluene-3-monooxygenase operon is uninduced and high when expression of tbuA1UBVA2C is induced by toluene. Thus, the toluene-3-monooxygenase promoter drives the cascade expression of both the toluene-3-monooxygenase operon and tbuT, resulting in a positive feedback circuit. Examination of the nucleotide sequence upstream of the toluene-3-monooxygenase operon for promoter-like sequences revealed a -24 TGGC, -12 TTGC sequence, characteristic of sigma54 (rpoN)-dependent promoters. Primer extension and tbuA1-lacZ fusion analyses demonstrated that this -24, -12 promoter sequence, referred to as PtbuA1, was the toluene-3-monooxygenase promoter. Upstream of PtbuA1, a DNA region with dyad symmetry exhibited homology with the XylR-binding site present upstream of the Pu promoter. Deletions within this DNA sequence resulted in complete loss of expression from PtbuA1, suggesting that this region may serve as the TbuT-binding site. PMID:8892837

  16. Biofiltration of air contaminated with methanol and toluene

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Kulay, Luiz Alexandre

    2012-01-01

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

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

    Scientific Electronic Library Online (English)

    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.

  19. Spatial variability in levels of benzene, formaldehyde, and total benzene, toluene, ethylbenzene and xylenes in New York City: a land-use regression study

    OpenAIRE

    Kheirbek Iyad; Johnson Sarah; Ross Zev; Pezeshki Grant; Ito Kazuhiko; Eisl Holger; Matte Thomas

    2012-01-01

    Abstract Background Hazardous air pollutant exposures are common in urban areas contributing to increased risk of cancer and other adverse health outcomes. While recent analyses indicate that New York City residents experience significantly higher cancer risks attributable to hazardous air pollutant exposures than the United States as a whole, limited data exist to assess intra-urban variability in air toxics exposures. Methods To assess intra-urban spatial variability in exposures to common ...

  20. Apparent Benzene Solubility in Tetraphenylborate Slurries

    International Nuclear Information System (INIS)

    Personnel conducted testing to determine the apparent solubility of benzene in potassium tetraphenylborate (KTPB) slurries. The lack of benzene vapor pressure suppression in these tests indicate that for a 6.5 wt percent solids KTPB slurry in 4.65 M Na+ salt solution at approximately 25 degrees Celsius, no significant difference exists between the solubility of benzene in the slurry and the solubility of benzene in salt solution without KTPB solids. The work showed similar results in slurry with 6,000 mg/L sludge and 2,000 mg/L monosodium titanate added. Slurries containing tetraphenylborate decomposition intermediates (i.e., 4,200 mg/L triphenylboron (3PB), 510 mg/L diphenylborinic acid (2PB) and 1,500 mg/L phenylboric acid (1PB) or 100 mg/L tri-n-butylphosphate (TBP)) also showed no significant difference in benzene solubility form filtrate containing no KTPB solids. Slurry containing 2,000 mg/L Surfynol 420 did exhibit significant additional benzene solubility, as did irradiated slurries. The vapor pressure depression in the irradiated slurries presumably results from dissolution of biphenyl and other tetraphenylborate irradiation products in the benzene

  1. Crystal structure of ethyl 2-(2,4,5-tri-meth-oxy-phen-yl)quinoline-4-carboxyl-ate.

    Science.gov (United States)

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

    2015-07-01

    In the title compound, C21H21NO5, the dihedral angle between the quinoline ring system (r.m.s. deviation = 0.028?Å) and the tri-meth-oxy-benzene ring is 43.38?(5)°. The C atoms of the meth-oxy groups deviate from their attached benzene ring by -0.396?(2), -0.049?(2) and 0.192?(2)?Å 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 intra-molecular C-H?O contact closes an S(6) ring. In the crystal, inversion dimers linked by pairs of weak C-H?O inter-actions generate R 2 (2)(6) loops. The dimers are linked by further C-H?O inter-actions to generate [1-10] chains. PMID:26279938

  2. Synergistic effect of catalyst for oxidation removal of toluene.

    Science.gov (United States)

    Zhu, Tao; Li, Jian; Liang, Wenjun; Jin, Yuquan

    2009-06-15

    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 MnO(2)/gamma-Al(2)O(3) as catalyst. The removal efficiency of toluene was significantly increased by combining MnO(2)/gamma-Al(2)O(3) with NTP. At the same time, the goal of improving energy efficiency and decreasing O(3) from exhaust gas treatment was accomplished. PMID:19124193

  3. Excision of pyrimidine dimers in toluene-treated Escherichia coli

    International Nuclear Information System (INIS)

    Toluene-treated cells were used for examining excision of pyrimidine dimers in Escherichia coli strains W3110, DM845 (uvrA-), P3478 (polA-), and KS5064 (polA/sub ex1/). Excision occurring in toluene-treated cells is rapid adenosine 5'-triphosphate dependent, and requires the uvrA gene function. In strains lacking either the polymerizing or 5' ? 3' exonucleolytic activity of deoxyribonucleic acid polymerase I, excision does occur. However, both in vivo and in vitro, the excision in such strains is initially slower than wild type

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

    DEFF Research Database (Denmark)

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

    1987-01-01

    The urinary excretion of hippuric acid (HA) and ortho-cresol (O-cr) in man was measured in two studies of 7-h exposure to toluene in a climate chamber, either constant concentration of 100 ppm or varying concentrations containing peaks of 300 ppm but with a time-weighted average of 100 ppm. In Study A, four males were exposed to clean air and to constant and varying concentrations of toluene in combination with rest and with 100 W exercise in 140 min. Exercise increased end exposure excretion ra...

  5. Extraction of reduced ?-silicomolybdic acid with trioctylamine in toluene

    International Nuclear Information System (INIS)

    Reductive extraction of ?-molybdosilicic heteropolyacid (?-MSA) with trioctylamine (TOA) in toluene has been investigated. The composition of extracted compound, determined by the isomolar series method, is characterized by the ratio o ?-MSA:TOA approximately 1:4. Complexes with greater saturation are also partially formed, which is proved by the elementary analysis of the isolated ?-MSA complex with TOA. Dissociation of the ?-MSA complex with TOA in toluene has been detected conductometrically. The complex has been found to dissociate with the splitting-off of four protonated amine particles. The extraction constant, with the dissociation of the complex taken into account, is equal to approximately 10sup(7.5)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Aromaticity of benzene in condensed phases. A case of a benzene-water system

    Science.gov (United States)

    Zborowski, Krzysztof K.

    2014-05-01

    A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

  8. Radiocarbon dating methods using benzene liquid scintillation

    International Nuclear Information System (INIS)

    The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

  9. Genetic effects of thinner, benzene and toluene in Drosophila melanogaster. 1. Sex Chromosome loss and non-disjunction

    Directory of Open Access Journals (Sweden)

    Rosario Rodríguez Arnaiz

    1985-01-01

    Full Text Available Se estudiaron algunos efectos genéticos de tiner, benceno y tolueno en Drosophila melanogaster, tales como la pérdida de los cromosomas sexuales y la no disyunción de los mismos en machos y en hembras. El orden de toxicidad fue benceno > tolueno > tiner. La viabilidad se redujo con el benceno y el tolueno pero no con el tíner. Solamente las concentraciones más altas de benceno y tolueno indujeron la pérdida de los cromosomas sexuales y la no disyunción en los machos. El tiner no produjo dichos efectos genéticos.

  10. Benzene and toluene influence with or without nitrogen dioxide on inorganic pigments of works of art—Part II

    Science.gov (United States)

    Agelakopoulou, T.; Bassiotis, I.; Metaxa, E.; Roubani-Kalantzopoulou, F.

    Air pollution has a great impact on the social and economic aspects all over the world. In order to account the human interaction with the atmospheric environment, a suitable scientific basis is needed. That is why six physicochemical quantities have been determined in a previous work for each one heterogeneous system between organic volatile pollutants and oxide-pigments of works of art. This investigation is extended in order to determine experimentally five new ones. Thus, a more precise contribution to the elucidation of the mechanism of the deterioration of various works of art in museums is achieved. These physicochemical quantities are: (1) local adsorption energies, (2) local monolayer capacities, (3) local adsorption isotherms, (4) density probability function, and (5) pollutant concentration on the oxide-pigment at equilibrium. All these adsorption parameters mentioned above have been calculated as a function of experimental time for the systems: C 6H 6/TiO 2, C 6H 6/NO 2/TiO 2, C 6H 6/Cr 2O 3, C 6H 6/NO 2/Cr 2O 3, C 6H 5CH 3/TiO 2, C 6H 5CH 3/NO 2/TiO 2, C 6H 5CH 3/Cr 2O 3, C 6H 5CH 3/NO 2/Cr 2O 3, C 6H 6/PbO, C 6H 6/NO 2/PbO, C 6H 5CH 3/PbO, and C 6H 5CH 3/NO 2/PbO for the first time. Thus, in this work we shall stress the recent new aspect of Reversed Flow-(Inverse) Gas Chromatography (RF-GC or RF-IGC), i.e. the time-resolved chromatography related to the evaluation of some important adsorption parameters. Gas Chromatography is a promising meeting place of surface science and atmospheric chemistry.

  11. Growth of the fungus Cladosporium sphaerospermum with toluene as the sole carbon and energy source.

    OpenAIRE

    Weber, F.J.; Hage, K C; De Bont, J.A.M.

    1995-01-01

    The fungus Cladosporium sphaerospermum was isolated from a biofilter used for the removal of toluene from waste gases. This is the first report describing growth of a eukaryotic organism with toluene as the sole source of carbon and energy. The oxygen consumption rates, as well as the measured enzyme activities, of toluene-grown C. sphaerospermum indicate that toluene is degraded by an initial attack on the methyl group.

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

    DEFF Research Database (Denmark)

    Bælum, Jesper; DØssing, M

    1987-01-01

    The urinary excretion of hippuric acid (HA) and ortho-cresol (O-cr) in man was measured in two studies of 7-h exposure to toluene in a climate chamber, either constant concentration of 100 ppm or varying concentrations containing peaks of 300 ppm but with a time-weighted average of 100 ppm. In Study A, four males were exposed to clean air and to constant and varying concentrations of toluene in combination with rest and with 100 W exercise in 140 min. Exercise increased end exposure excretion rate of HA and O-cr by 47 and 114%, respectively. After exposure, all excess HA was excreted within 4 h, while O-cr was eliminated with a half life of about 3 h. Alveolar air concentration of toluene varied between 21 and 31 ppm during constant exposure and between 13 and 57 ppm during varying exposure, but no difference in mean alveolar toluene concentration or in metabolite excretion was seen 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 implementing either of them as biological exposure indices, the influence of sex, body size, age as well as consumption of tobacco and alcohol has to be considered.

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

    DEFF Research Database (Denmark)

    DØssing, M; Bælum, Jesper

    1984-01-01

    In a climatic exposure chamber four healthy volunteers were exposed to 100ppm toluene, 100ppm toluene + ethanol, 100ppm toluene + cimetidine, and 100ppm toluene + propranolol for 7h each at random over four consecutive days. A control experiment and 3.5h of exposure to 200ppm toluene were also performed. Ethanol inhibited toluene metabolism by 0.5 as expressed by the urinary excretion of two of the metabolites of toluene, namely o-cresol and hippuric acid. In agreement with this, the mean alveolar concentration of toluene was greater by 1.7 during ethanol exposure; 45 min after discontinuation of exposure the increase was by 3.3. Neither cimetidine nor propranolol changed toluene metabolism significantly. The results indicate that ethanol may prolong the time interval in which toluene is retained in the human body in persons simultaneously exposed to ethanol and toluene. When using o-cresol or hippuric acid in biological monitoring of persons occupationally exposed to toluene, the consumption of ethanol should be considered.

  14. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Science.gov (United States)

    2010-07-01

    ... Toluene sulfonamide bis-phe-nol A epoxy adduct. 721.1850 Section 721.1850... Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical substances and...generically as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is...

  15. Transport and biodegradation of toluene in unsaturated soil

    Science.gov (United States)

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

    1994-12-01

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

  16. Dynamics of Na(+)(Benzene) + Benzene Association and Ensuing Na(+)(Benzene)2* Dissociation.

    Science.gov (United States)

    Paul, Amit K; Kolakkandy, Sujitha; Hase, William L

    2015-07-16

    Chemical dynamics simulations were used to study Bz + Na(+)(Bz) ? Na(+)(Bz)2* association and the ensuing dissociation of the Na(+)(Bz)2* cluster (Bz = benzene). An interesting and unexpected reaction found from the simulations is direct displacement, for which the colliding Bz molecule displaces the Bz molecule attached to Na(+), forming Na(+)(Bz). The rate constant for Bz + Na(+)(Bz) association was calculated at 750 and 1000 K, and found to decrease with increase in temperature. By contrast, the direct displacement rate constant increases with temperature. The cross section and rate constant for direct displacement are approximately an order of magnitude lower than those for association. The Na(+)(Bz)2* cluster, formed by association, dissociates with a biexponential probability, with the rate constant for the short-time component approximately an order of magnitude larger than that for the longer time component. The latter rate constant agrees with that of Rice-Ramsperger-Kassel-Marcus (RRKM) theory, consistent with rapid intramolecular vibrational energy redistribution (IVR) and intrinsic RRKM dynamics for the Na(+)(Bz)2* cluster. A coupled phase space model was used to analyze the biexponential dissociation probability. PMID:25938260

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

    KAUST Repository

    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.

  18. Radiolysis of Aqueous Benzene Solutions

    International Nuclear Information System (INIS)

    Aerated and deaerated aqueous solutions of benzene have been irradiated with 60Co ?-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

  19. Benzene toxicity of the occurrence of benzene in the ambient air of the Houston area

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.C.

    1980-01-01

    This study was conducted by either literature review or actual field survey. Results are summarized as follows: (1) long-term occupational exposure of workers to benzene vapor at levels of 3 to 7 ppM, 2 to 3 ppM and 1.6 ppM may result in a decreased level of leucocyte alkaline phosphates, an increased incidence of chromosome aberrations and an increased level of ALA in erythrocytes, respectively; (2) benzene is capable of causing fetotoxic effects in animals at levels as low as 10 ppM by volume; (3) exposure of animals to or less than 1 ppM benzene vapor may result in leucopenia, an inverse ratio of muscle antagonist chronaxy and a decreased level of ascorbic acid in fetus's and mother's liver as well as whole embryo; (4) benzene is causally associated with the increased incidence of pancytopenia, including unicytopenia, bicytopenia and aplastic anemia, and chromosome aberrations in occupational exposure population, and at best benzene must also be considered as a leukemogen; (5) since it can be emitted into the atmosphere from both man-made and natural sources, benzene in some concentrations is presented everywhere in the various compartments of the environment; (6) the findings of the emission of benzene from certain natural sources indicate that reducing benzene to a zero-level of exposure is theoretically impossible; (7) the annual average of benzene concentration detected in the Houston ambient air is 2.50 ppB, which is about 2.4 times higher than the nation-wide annual average exposure level and may have some health implications to the general public; and (8) in the Houston area, stationary sources are more important than mobile sources in contributing to benzene in the ambient air.

  20. Synergistic effects of non-thermal plasma-assisted catalyst and ultrasound on toluene removal.

    Science.gov (United States)

    Sun, Yongli; Zhou, Libo; Zhang, Luhong; Sui, Hong

    2012-01-01

    A wire-mesh catalyst coated by La0.8Sr0.2MnO3 was combined with a dielectric barrier discharge (DBD) reactor for toluene removal at atmospheric pressure. It was found that toluene removal efficiency and carbon dioxide selectivity were enhanced in the catalytic packed-bed reactor. In addition, ozone and nitrogen monoxide from the gas effluent byproducts decreased. This is the first time that ultrasound combined with plasma has been used for toluene removal. A synergistic effect on toluene removal was observed in the plasma-assisted ultrasound system. At the same time, the system increased toluene conversion and reduced ozone emission. PMID:22893967

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

    DEFF Research Database (Denmark)

    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 produc...

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

    DEFF Research Database (Denmark)

    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 identical reaction conditions.

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

    Scientific Electronic Library Online (English)

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

    2003-05-01

    Full Text Available [...] Abstract in english 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 t [...] ransalkylation 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 formation. This is explained in terms of the mordenite structure and the presence of hydrogen.

  4. Interação de glyphosate com carfentrazone-ethyl / Glyphosate - carfentrazone-ethyl interaction

    Scientific Electronic Library Online (English)

    R.C., Werlang; A.A., Silva.

    2002-04-01

    Full Text Available Foi conduzido um experimento em condições controladas para determinar a interação do carfentrazone-ethyl em mistura no tanque com o herbicida glyphosate, no controle de seis espécies de plantas daninhas. Glyphosate aplicado isoladamente na dose de 720 g ha-1 foi eficaz no controle de Amaranthus hybr [...] idus (100%), Desmodium tortuosum (100%), Bidens pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) e Commelina benghalensis (93%) aos 21 DAA. Carfentrazone-ethyl aplicado isoladamente controlou eficazmente C. benghalensis. As misturas de glyphosate nas doses de 252 e 720 g ha-1 com carfentrazone-ethyl nas doses de 15 e 30 g ha¹ demonstraram efeito aditivo no controle de A. hybridus, D. tortuosum e Bidens pilosa, à exceção das misturas de glyphosate na dose de 252 g ha-1 com as doses de 15 e 30 g ha-1 de carfentrazone-ethyl, que proporcionam efeito sinergístico no controle de D. tortuosum. A adição das duas doses de carfentrazone-ethyl antagonizou o efeito de glyphosate na menor dose (252 g ha-1) no controle de E. indica, apresentando, no entanto, efeito aditivo com o glyphosate na maior dose (720 g ha-1). Já para D. horizontalis, as misturas de carfentrazone-ethyl com glyphosate na menor dose (252 g ha-1) apresentaram efeito sinergístico no controle dessa espécie, demonstrando, ainda, efeito aditivo na mistura com glyphosate na dose de 720 g ha-1. A mistura de carfentrazone-ethyl com glyphosate proporcionou efeito aditivo no controle de C. benghalensis, independentemente das combinações de doses avaliadas. Os resultados deste experimento indicam que carfentrazone-ethyl apresenta comportamento diferenciado quanto à interação com glyphosate, dependendo da espécie de planta daninha e da dose dos herbicidas utilizados na mistura em tanque, sendo complementar na mistura em tanque com glyphosate, pois demonstrou efeito antagônico em poucas das combinações estudadas, prevalecendo seu efeito aditivo na mistura com glyphosate, no controle das espécies avaliadas. Abstract in english Under evironmental controlled conditions experiments were conducted to determine the efficacy of carfentrazone-ethyl in tank mixture with glyphosate to control six weed species. Glyphosate alone at 720 g ha-1 was effective in controlling Amaranthus hybridus (100%), Desmodium tortuosum (100%), Bidens [...] pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) and Commelina benghalensis (93%) at 21 DAA. Carfentrazone-ethyl alone controlled only C. benghalensis. efficiently. Glyphosate mixtures (252 and 720 g ha-1) with carfentrazone-ethyl at 15 and 30 g ha¹ showed an additive effect in controlling A. hybridus, D. tortuosum and Bidens pilosa, except for glyphosate mixture at 252 g ha-1 with carfentrazone-ethyl at 15 and 30 g ha-1, which showed synergism in controlling D. tortuosum. The addition of the two carfentrazone-ethyl doses antagonized the effect of the smallest dose (252 g ha-1) of glyphosate on E. indica control. However, the largest glyphosate dose (720 g ha-1) provided additive effect when mixed with both carfentrazone-ethyl doses. For D. horizontalis, carfentrazone-ethyl mixtures with glyphosate in the smallest dose (252 g ha-1) had a synergistic effect in the control of this species, also showing and additive effect in the mixture with glyphosate at 720 g ha-1. Carfentrazone-ethyl mixture with glyphosate provided an additive effect in C. benghalensis control, regardless of dose combinations. The results of this experiment indicate that carfentrazone-ethyl presents a differentiated behavior when interacting with glyphosate, depending on the weed species and the herbicide dose used in the tank mixtures, being complementary in tank-mix combinations with glyphosate, since it showed an antagonistic effect in few combinations, with its additive effect prevailing in the mixture with glyphosate for the control of the evaluated species.

  5. Interação de glyphosate com carfentrazone-ethyl Glyphosate - carfentrazone-ethyl interaction

    Directory of Open Access Journals (Sweden)

    R.C. Werlang

    2002-04-01

    Full Text Available Foi conduzido um experimento em condições controladas para determinar a interação do carfentrazone-ethyl em mistura no tanque com o herbicida glyphosate, no controle de seis espécies de plantas daninhas. Glyphosate aplicado isoladamente na dose de 720 g ha-1 foi eficaz no controle de Amaranthus hybridus (100%, Desmodium tortuosum (100%, Bidens pilosa (99%, Eleusine indica (96%, Digitaria horizontalis (100% e Commelina benghalensis (93% aos 21 DAA. Carfentrazone-ethyl aplicado isoladamente controlou eficazmente C. benghalensis. As misturas de glyphosate nas doses de 252 e 720 g ha-1 com carfentrazone-ethyl nas doses de 15 e 30 g ha¹ demonstraram efeito aditivo no controle de A. hybridus, D. tortuosum e Bidens pilosa, à exceção das misturas de glyphosate na dose de 252 g ha-1 com as doses de 15 e 30 g ha-1 de carfentrazone-ethyl, que proporcionam efeito sinergístico no controle de D. tortuosum. A adição das duas doses de carfentrazone-ethyl antagonizou o efeito de glyphosate na menor dose (252 g ha-1 no controle de E. indica, apresentando, no entanto, efeito aditivo com o glyphosate na maior dose (720 g ha-1. Já para D. horizontalis, as misturas de carfentrazone-ethyl com glyphosate na menor dose (252 g ha-1 apresentaram efeito sinergístico no controle dessa espécie, demonstrando, ainda, efeito aditivo na mistura com glyphosate na dose de 720 g ha-1. A mistura de carfentrazone-ethyl com glyphosate proporcionou efeito aditivo no controle de C. benghalensis, independentemente das combinações de doses avaliadas. Os resultados deste experimento indicam que carfentrazone-ethyl apresenta comportamento diferenciado quanto à interação com glyphosate, dependendo da espécie de planta daninha e da dose dos herbicidas utilizados na mistura em tanque, sendo complementar na mistura em tanque com glyphosate, pois demonstrou efeito antagônico em poucas das combinações estudadas, prevalecendo seu efeito aditivo na mistura com glyphosate, no controle das espécies avaliadas.Under evironmental controlled conditions experiments were conducted to determine the efficacy of carfentrazone-ethyl in tank mixture with glyphosate to control six weed species. Glyphosate alone at 720 g ha-1 was effective in controlling Amaranthus hybridus (100%, Desmodium tortuosum (100%, Bidens pilosa (99%, Eleusine indica (96%, Digitaria horizontalis (100% and Commelina benghalensis (93% at 21 DAA. Carfentrazone-ethyl alone controlled only C. benghalensis. efficiently. Glyphosate mixtures (252 and 720 g ha-1 with carfentrazone-ethyl at 15 and 30 g ha¹ showed an additive effect in controlling A. hybridus, D. tortuosum and Bidens pilosa, except for glyphosate mixture at 252 g ha-1 with carfentrazone-ethyl at 15 and 30 g ha-1, which showed synergism in controlling D. tortuosum. The addition of the two carfentrazone-ethyl doses antagonized the effect of the smallest dose (252 g ha-1 of glyphosate on E. indica control. However, the largest glyphosate dose (720 g ha-1 provided additive effect when mixed with both carfentrazone-ethyl doses. For D. horizontalis, carfentrazone-ethyl mixtures with glyphosate in the smallest dose (252 g ha-1 had a synergistic effect in the control of this species, also showing and additive effect in the mixture with glyphosate at 720 g ha-1. Carfentrazone-ethyl mixture with glyphosate provided an additive effect in C. benghalensis control, regardless of dose combinations. The results of this experiment indicate that carfentrazone-ethyl presents a differentiated behavior when interacting with glyphosate, depending on the weed species and the herbicide dose used in the tank mixtures, being complementary in tank-mix combinations with glyphosate, since it showed an antagonistic effect in few combinations, with its additive effect prevailing in the mixture with glyphosate for the control of the evaluated species.

  6. 40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ...false Quizalofop ethyl; tolerances for residues. 180.441 Section 180.441 ...AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.441 Quizalofop ethyl; tolerances for residues. (a) General. (1)...

  7. Performances of toluene removal by activated carbon derived from durian shell.

    Science.gov (United States)

    Tham, Y J; Latif, Puziah Abdul; Abdullah, A M; Shamala-Devi, A; Taufiq-Yap, Y H

    2011-01-01

    In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model. PMID:20884200

  8. N-Ethyl-N-phenyl-p-toluenesulfonamide

    Directory of Open Access Journals (Sweden)

    Islam Ullah Khan

    2010-04-01

    Full Text Available In the title compound, C15H17NO2S, the aromatic rings are oriented at a dihedral angle of 32.8?(1°. The ethyl group and phenyl ring on the N atom adopt a staggered conformation with respect to the O atoms.

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

    International Nuclear Information System (INIS)

    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.

  10. 21 CFR 172.872 - Methyl ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2009-04-01 true Methyl ethyl cellulose. 172.872 Section 172.872 Food...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in...

  11. Perylenetetracarboxylic diimide (PTCDI) nanowires for sensing ethyl acetate in wine.

    Science.gov (United States)

    Khopkar, Yashdeep; Kojtari, Arben; Swearer, Dayne; Zivanovic, Sandra; Ji, Hai-Feng

    2014-09-01

    We report the application of perylenetetracarboxylic diimide (PTCDI) nanowires for sensing ethyl acetate. The conductivity of the crystalline nano/microwires increases quickly and selectively in the presence of ethyl acetate vapor, but not with water, acid and alcohol vapors, suggesting that the nanowires of PTCDI may be used for monitoring ethyl acetate during a wine manufacturing process. PMID:25924331

  12. Interação de glyphosate com carfentrazone-ethyl Glyphosate - carfentrazone-ethyl interaction

    OpenAIRE

    R.C. Werlang; Silva, A. A.

    2002-01-01

    Foi conduzido um experimento em condições controladas para determinar a interação do carfentrazone-ethyl em mistura no tanque com o herbicida glyphosate, no controle de seis espécies de plantas daninhas. Glyphosate aplicado isoladamente na dose de 720 g ha-1 foi eficaz no controle de Amaranthus hybridus (100%), Desmodium tortuosum (100%), Bidens pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) e Commelina benghalensis (93%) aos 21 DAA. Carfentrazone-ethyl aplicado isoladamen...

  13. Thermodynamic properties of benzene under shock conditions

    Science.gov (United States)

    Maillet, Jean-Bernard; Pineau, Nicolas

    2008-06-01

    We present in this paper a thermodynamic analysis of benzene properties under shock conditions as given by molecular dynamics (MD) simulations. Reactive MD simulations of benzene predict a decomposition threshold corresponding to the flection point on the experimental Hugoniot curve. A polymerlike carbonated structure is observed for pressures above this threshold, but the calculated Hugoniot curve is in disagreement with the experimental one at high pressure. On the contrary, a system consisting of a diamond cluster in hydrogen gas leads to a correct prediction of the pressure on the Hugoniot curves. The central question is then linked to the kinetics of the transition between the polymerlike structure and the diamond cluster.

  14. Analysis of a Recent Biofilter Model for Toluene Biodegradation

    OpenAIRE

    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...

  15. Reactivity and Microstructure in Water / Ethoxy Alcohols / Toluene Ternary Solutions

    OpenAIRE

    PELIZZETTI, Ezio; Minero, Claudio

    1995-01-01

    The phase diagrams of several ethoxylated alcohols in the presence of water and toluene are reported. From their behaviour and from data obtained through conductivity, light scattering, C-13-NMR, index of refraction, static dielectric constant and kinetic measurements, we had the evidence of microscopic structuration in some of the systems. The kinetic data for the electron transfer reaction between tetrabromo-1,2-benzoquinone and 1,4-benzenediol obtained in the ternary system water/C2E1/tolu...

  16. Eco friendly nitration of toluene using modified zirconia

    Directory of Open Access Journals (Sweden)

    K.R. Sunaja Devi

    2013-03-01

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

  17. Two cases of paraoccupational asthma due to toluene diisocyanate (TDI)

    OpenAIRE

    De Zotti, R; Muran, A; Zambon, F

    2000-01-01

    Two cases of paraoccupational asthma caused by toluene diisocyanate (TDI) are reported. The first patient was a metal worker in a machine shop situated near a factory producing polyurethane foam. Symptoms at work were not explainable by any specific exposure to irritants or allergens in the work site. As the patient recalled previous occasional work in the adjacent polyurethane factory with accompanying worsening of respiratory symptoms, a specific inhalation (SIC) test was performed with TDI...

  18. Developmental neurotoxicity after toluene inhalation exposure in rats

    DEFF Research Database (Denmark)

    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 TG for Developmental Neurotoxicity Study, i.e., physical development, reflex ontogeny, motor function, motor activity, sensory function, and learning and memory. The exposure did not cause maternal toxi...

  19. Modeling biodegradation of toluene in rotating drum biofilter.

    Science.gov (United States)

    Yang, C P; Chen, H; Zeng, G M; Qu, W; Zhong, Y Y; Zhu, X; Suidan, M T

    2006-01-01

    Rotating drum biofilters (RDBs) are cost-effective for control of emissions of volatile organic compounds (VOCs) from waste gas streams. In this paper, a dynamic mathematical model is presented which simulates and predicts the variation in performance of a multi-layer RDB with time on the basis of the two-film theory. The model takes into account factors including biofilm growth and biomass loss, and a changing biofilm surface area and thickness assuming quasi-steady-state conditions in the two-phase system and uniform bacterial population. Toluene was assumed to be the only rate-limiting substrate. The model equations for the gas-phase mass balance and biofilm growth were solved using MATLAB based on the fourth-fifth-order Runge-Kutta technique, and the concentration profiles in the biofilms were obtained using the method of orthogonal collocation. Simulation results showed that the toluene removal efficiency decreased with increased toluene loading or increased duration of operation of the biofilter. Calculation results were compared to the experimental results, which demonstrated that the dynamic model provided a good simulation of the performance of the biofilter. PMID:17163052

  20. Benzene degradation coupled with chlorate reduction in soil column study

    OpenAIRE

    Tan, N.C.G.; Doesburg, W.C.J., van; Langenhoff, A. A. M.; Stams, A. J. M.

    2006-01-01

    Perchlorate and chlorate are electron acceptors that during reduction result in the formation of molecular oxygen. The produced oxygen can be used for activation of anaerobic persistent pollutants, like benzene. In this study chlorate was tested as potential electron acceptor to stimulate benzene degradation in anoxic polluted soil column. A chlorate amended benzene polluted soil column was operated over a period of 500 days. Benzene was immediately degraded in the column after start up, and ...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 13C-nuclear magnetic resonance study of benzene derivatives, ketones, and 1-hexene adsorbed on silica-gel, silver-silica-gel, and trimethylsilanized-silica-gel

    International Nuclear Information System (INIS)

    13C-NMR measurements of benzene derivatives (benzene, toluene, o-xylene, m-xylene, p-xylene), ketones (acetone, methylethylketone), and l-hexene adsorbed on silica-gel, Ag-silica-gel, and TMS-silica-gel (trimethylsilanized-silica-gel) were carried out. Upon adsorption, all the methyl carbons of benzene derivatives showed upper field shifts ((0.8 -- 2.4)ppm) irrespective of adsorbents. In the case of benzene derivatives adsorbed on Ag-silica-gel, ring carbons at which a methyl group bonded gave lower field shifts ((0.6 -- 0.9)ppm), whereas other ring carbons showed upper field shifts ((0.8 -- 4.4)ppm). These chemical shifts data suggest a formation of ?-complex between surface silver ions and benzene rings. A C1 carbon of l-hexene on Ag-silica-gel gave an upper field shift (10.4 ppm) and gave the same result as benzene derivatives. All the carbonyl carbons of ketones adsorbed on any of silica-gel and modified ones showed a characteristic lower field chemical shift based on hydrogen bonds between carbonyl groups and surface silanol groups (=Si-OH) of various silica-gels. 13C-NMR spectra of the trimethylsilyl group (TMS-group) of TMS-silica-gel dispersed in various solvents were also measured. The TMS-group showed a broad line width (98Hz) and an upper field chemical shift (4.1 ppm) in the dry state, whereas, upon dispersing in solvents, both the line width and the chemical shifts were reduced to about half of those obtained without solvents. (author)

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

    Directory of Open Access Journals (Sweden)

    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...? 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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 ?-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...? and ?–? interactions.

  7. Recommended sublimation pressure and enthalpy of benzene.

    Czech Academy of Sciences Publication Activity Database

    R?ži?ka, K.; Fulem, Michal; ?ervinka, C.

    2014-01-01

    Ro?. 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

  8. Formation of Benzene in the Interstellar Medium

    Science.gov (United States)

    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.

  9. Modeling of hydrocracking of heavy benzene fraction

    Energy Technology Data Exchange (ETDEWEB)

    Zhorov, Yu.M.; Agafonov, A.V.; Khavkin, V.A.; Kozlov, I.T.; Panchenkov, G.M.; Tatarintseva, G.M.

    1980-01-01

    A chemical scheme and mathematical description of the hydrocracking process was developed, taking into account transformation of individual hydrocarbons. Demonstrates usefulness of data performed at pilot study. Gives hydrocracking results for individual hydrocarbons and heavy benzene fraction; determines effective conditions for deriving isoparaffin hydrocarbons C/sub 4/-C/sub 6/.

  10. Ordered mesoporous carbon film as an effective solid-phase microextraction coating for determination of benzene series from aqueous media.

    Science.gov (United States)

    Jiang, Hui; Li, Jiansheng; Jiang, Mingyue; Lu, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing; Wang, Lianjun

    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(2)/g. Scanning electron microscopy (SEM) studies show the supported OMC film with thickness at 8.5 ?m 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 ?g/L), low detection limits (0.01-0.05 ?g/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. PMID:26320962

  11. (E-Ethyl N?-(4-bromobenzylidenehydrazinecarboxylate

    Directory of Open Access Journals (Sweden)

    Bo Gao

    2008-08-01

    Full Text Available The title compound, C10H11BrN2O2, crystallizes with two independent molecules in the asymmetric unit, in which the dihedral angles between the benzene ring and the hydrazine carboxylic acid mean plane are 3.0?(4 and 45.3?(3°. The molecules are linked into a one-dimensional network by intermolecular N—H...O hydrogen bonds.

  12. PREFRACTIONATION OF HIGH BENZENE PRECURSORS’ FEED FOR HYBRID REFORMER UNIT

    OpenAIRE

    K. Kirilov; M. Chomakov; D. Stratiev; R. Dinkov

    2008-01-01

    Benzene is toxic air pollutant and that’s why is set a constraint to 1% (v/v) in gasoline. Refiners have to lower benzene in its gasoline pool components. High benzene contributors are reformate and FCC gasoline. Worldwide practice is to optimize the reformate benzene content. Some light crude oils, like Samgori from Georgia contain more fraction with boiling temperature interval from 60 to 85oC. This fraction is an indicator for benzene precursors content in gasoline. There is a possibility ...

  13. 3H-benzene metabolism in rabbit bone marrow

    International Nuclear Information System (INIS)

    An assay for benzene metabolism using 3H-benzene and high pressure liquid chromatography was developed. 3H-benzene metabolism (2 pmoles benzene equivalents/mg protein/min) required the presence of a TPNH generating system and was inhibited 80% in the presence of a CO:O2 (9:1) atmosphere. The products of 3H-benzene rabbit bone marrow microsomal metabolism were phenol and an unidentified metabolite. Cytochrome P-450 (26 to 51 pmoles/mg microsomal protein) and cytochrome c reductase activity (7.8 to 21.0 nmole/mg microsomal protein/min) were detected in rabbit bone marrow

  14. Adsorption of gases on benzene-preplated graphite

    Science.gov (United States)

    Asada, H.; Udaka, M.; Jitoue, Y.; Furukawa, J.

    1996-06-01

    We measured volumetrically adsorption isotherms of N 2, Ar, CH 4, and Kr on benzene-preplated graphite at 77 K. N 2 and Ar exhibit a new step on the isotherm at 5.0 and 4.3 Torr, respectively, suggesting some phase transition of the gases adsorbed on a single layer of benzene. On the other hand, CH 4 and Kr show layerwise condensation transitions even when one monolayer of benzene is preadsorbed, implying that benzene is displaced by these gases, but to the smallest extent among those observed previously for other systems. Benzene is also found to be soluble in N 2, Ar, and Kr.

  15. Synthesis of Ethyl Salicylate Using Household Chemicals

    Science.gov (United States)

    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.

  16. Dissolved hydrocarbon metabolism: the concentration-dependent kinetics of toluene oxidation in some North American estuaries

    International Nuclear Information System (INIS)

    The metabolism of toluene by natural populations of marine bacteria, stored to enhance their activity, gave hyperbolic kinetics with saturation at only K/sub t/ = 0.6 to 3.4 ?g liter-1. Similarly K/sub t/ in fresh seawater was 0.26 ?g toluene liter-1. Freshly collected populations could be moderately active toward toluene. These moderate affinities taken together with the small K/sub t/ values give an explanation for the failure of most marine bacteria to grow at the expense of a single hydrocarbon. In two experiments there was a significant first-order region in toluene in the 10-50 ?g liter-1 range. A large widespread population of bacteria with inducible capacity to metabolize hydrocarbons is indicated. Observed turnover times for toluene were 0.2-40 years with growth rates of 10-6h-1 from toluene at 1 ?g liter-1

  17. Composition depth profiling of polystyrene/poly(vinyl ethyl ether) blend thin films by angle resolved XPS

    International Nuclear Information System (INIS)

    Angle resolved XPS (ARXPS) and scanning force microscopy (SFM) are used to study polystyrene/poly(vinyl ethyl ether) 50/50 wt% blend thin films spin cast from toluene solution, as a function of polystyrene molecular weight and film thickness. ARXPS is used to investigate the composition depth profile (CDP) of the blend thin films and SFM to study their surface morphology and miscibility. The CDPs are modelled by an empirical hyperbolic tangent function with three floating parameters. These are determined by non-linear least squares regression, their uncertainties estimated and the curve fit residuals analysed to demonstrate that the hyperbolic tangent CDP is a satisfactory fit to the ARXPS data. Conclusions are drawn regarding the behaviour of the blend thin films as the thickness and polystyrene molecular weight are varied. Flory-Huggins interaction parameters (?) for the mixtures are calculated based upon the segregation data, and suggest a value of ? = 0.05 to be appropriate for this system.

  18. Energy transfer from cyclohexane to benzene in their irradiated mixtures

    International Nuclear Information System (INIS)

    The fluorescence of both cyclohexane and benzene in their irradiated mixtures has been studied as a function of benzene concentration from ? 0.005 to 0.1 M. The quenching of the cyclohexane emission by benzene is found to be significantly greater than obtained under optical excitation conditions suggesting an important role for benzene as a scavenger of the geminate ion-pair precursor of the fluorescing state of cyclohexane. From diffusion models, a lower bound is established for the scavenging rate constant. An examination of the fluorescence from benzene leads to the conclusion that although the majority of benzene fluorescence drives from electronic energy transfer from excited cyclohexane, a large fraction (from 20 to 50% over the concentration range studied) is generated by recombining molecular ions. The intrinsic efficiency with which the recombining ions generate fluorescent states of benzene, however, appears to be peculiarly low. (author)

  19. Indicators of benzene emissions and exposure in Bangkok street

    International Nuclear Information System (INIS)

    Ambient benzene measurements were conducted for the first time at four air monitoring sites in the Bangkok metropolitan region (BMR), from January to December 2001. Analytical results show that the mean benzene concentrations range from 42.4 ?g/m3 at the Din Daeng urban site to 15.1 ?g/m3 at the Chaeng Wattana suburban site. The monitoring results show that at a larger distance from the roadside or a higher level from the street surface, the level of benzene decreases. Analysis of the ambient benzene concentrations was carried out with reference to meteorological influences and traffic density. In traffic analysis, the combined effects of street topography and traffic flows established high impact on the overall benzene concentration in Bangkok. Statistical analysis shows good correlations of blood benzene levels and trans, trans-muconic acid with ambient benzene and demonstrated substantial exposure from traffic

  20. Toluene removal by oxidation reaction in spray wet scrubber: experimental, modeling and optimization

    Directory of Open Access Journals (Sweden)

    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%.

  1. Anaerobic toluene oxidation to benzyl alcohol and benzaldehyde in a denitrifying Pseudomonas strain.

    OpenAIRE

    Altenschmidt, U; Fuchs, G.

    1992-01-01

    The denitrifying Pseudomonas strain K172 was grown with a generation time of 6 h to a cell density of 0.4 g (dry weight) per liter with toluene and nitrate as substrates. We found that anaerobic cell suspensions oxidize [14C]toluene first to [14C]benzyl alcohol and subsequently to [14C]benzaldehyde. This proves that the methyl group of toluene is oxidized without molecular oxygen to a hydroxymethyl group.

  2. Anaerobic activation of toluene and o-xylene by addition to fumarate in denitrifying strain T.

    OpenAIRE

    Beller, H. R.; Spormann, A M

    1997-01-01

    Anaerobic assays conducted with strain T, a denitrifying bacterium capable of mineralizing toluene to carbon dioxide, demonstrated that toluene-grown, permeabilized cells catalyzed the addition of toluene to fumarate to form benzylsuccinate. This reaction was not dependent on the presence of coenzyme A (CoA) or ATP. In the presence of CoA, formation of E-phenylitaconate from benzylsuccinate was also observed. Kinetic studies demonstrated that the specific rate of benzylsuccinate formation fro...

  3. Deuterium Isotope Effects in the Unusual Addition of Toluene to Fumarate Catalyzed by Benzylsuccinate Synthase†

    OpenAIRE

    Li, Lei; Marsh, E. Neil G.

    2006-01-01

    The first step in the anaerobic metabolism of toluene is a highly unusual reaction: the addition of toluene across the double bond of fumarate to produce (R)-benzylsuccinate that is catalyzed by benzylsuccinate synthase. Benzylsuccinate synthase is a member of the glycyl radicalcontaining family of enzymes, and the reaction is initiated by abstraction of a hydrogen atom from the methyl group of toluene. To gain insight into the free energy profile of this reaction, we have measured the kineti...

  4. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    OpenAIRE

    Sarwar, G.; 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...

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

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Arvin, E.

    1999-01-01

    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 l...

  6. Electrochemical Oxidation of Toluene on Glassy Carbon Electrodes in Organic Medium

    OpenAIRE

    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...

  7. Kinetic studies on four-coordinate chelate complexes of copper(II): isotopic ligand exchange of Bis(salicylaldiminato)copper(II) in toluene

    International Nuclear Information System (INIS)

    Isotopic exchange technique has been used to study the rate of ligand exchange of a series of 131I-labeled bis(N-R-salicylaldiminato)copper(II) complxes (R=ethyl,n-propyl,isopropyl,isobutyl,tert-butyl,neopentyl) in toluene as a function of the nature of R and properties of substituents X at the salicylaldehyde ring. The rate of exchange follows a two-term rate law, namely, r/sub ex/ = (k/sub s/ + k/sub ligand/[ligand])[complex]. The occurrence of k/sub s/ is found to be due to residual water in toluene, according to k/sub s = k/sub H2O/[H2O]. The equilibrium constants K(py) for the addition of pyridine to the complexes studied have been measured spectrophotometrically. From the variation of k/sub s/, k/sub ligand/, ?H(k/sub s/), ?H(k/sub ligand/), ?S(k/sub s/), ?S(k/sub ligand/), and K(py) with R and X, it is concluded that both the solvent and the ligand term in the observed rate equation can be explained by an associative mode of activation. 3 figures, 5 tables

  8. Active site dynamics of toluene hydroxylation by cytochrome P-450

    International Nuclear Information System (INIS)

    Rat liver cytochrome P-450 hydroxylates toluene to benzyl alcohol plus o-, m-, and p-cresol. Deuterated toluenes were incubated under saturating conditions with liver microsomes from phenobarbital-pretreated rats, and product yields and ratios were measured. Stepwise deuteration of the methyl leads to stepwise decreases in the alcohol/cresol ratio without changing the cresol isomer ratios. Extensive deuterium retention in the benzyl alcohols from PhCH2D and PhCHD2 suggests there is a large intrinsic isotope effect for benzylic hydroxylation. After replacement of the third benzylic H by D, the drop in the alcohol/cresol ratio was particularly acute, suggsting that metabolic switching from D to H within the methyl group was easier than switching from the methyl to the ring. Comparison of the alcohol/cresol ratio for PhCH3 vs PhCD3 indicated a net isotope effect of 6.9 for benzylic hydroxylation. From product yield data for PhCH3 and PhCD3, DV for benzyl alcohol formation is only 1.92, whereas DV for total product formation is 0.67 (i.e., inverse). From competitive incubations of PhCH3/PhCD3 mixtures D(V/K) isotope effects on benzyl alcohol formation and total product formation (3.6 and 1.23, respectively) are greatly reduced, implying strong commitment to catalysis. In contrast, D(V/K) for the alcohol/cresol ratio is 6.3, indicating that the majority of the intrinsic isotope effect is expressed through metabolic switching. Overall, these data are consistent with reversible formation of a complex between toluene and the active oxygen form of cytochrome P-450, which rearranges internally and reacts to form products faster than it dissociates back to release substrate

  9. Comparison of hair and nail ethyl glucuronide concentrations

    Directory of Open Access Journals (Sweden)

    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.

  10. Glass transition in vapor deposited thin films of toluene

    International Nuclear Information System (INIS)

    We report on nanocalorimetric measurements of 50 nm thick toluene films at heating rates spanning 600 to 8 x 104 K/s. The films are grown from the vapour at 90 K directly onto the nanocalorimetric cell. The kinetic and thermodynamic stability of as-deposited films is higher than the stability of films cooled from the supercooled liquid at 2000 K/s. We also show that at those heating rates, the calorimetric Tg does not correlate with the relaxation time obtained by dielectric spectroscopy.

  11. Vapor–Liquid Equilibrium in Diluted Polymer + Toluene Systems.

    Czech Academy of Sciences Publication Activity Database

    Bogdani?, Grozdana; Wichterle, Ivan

    Praha : ?eská spole?nost 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 ?R 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

  12. Crystal structure of ethyl N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-di­hydro-1H-pyrazol-4-yl)carbamate

    OpenAIRE

    Danish, Muhammad; Tahir, Muhammad Nawaz; Anwar, Uzma; Raza, Muhammad Asam

    2015-01-01

    In the title compound, C14H17N3O3, the dihedral angle between the benzene ring and the five-membered di­hydro­pyrazole ring is 52.26?(9)°. The ethyl ester group is approximately planar (r.m.s. deviation 0.0568?Å) and subtends an angle 67.73?(8)° to the pyrazole ring. In the crystal, molecules are linked by pairs of N—H?O hydrogen bonds, forming inversion dimers with an R 2 2(10) ring motif. Weaker C—H?O contacts link these dimers into a three-dimensional network of mol­ecules stacked al...

  13. Photoelectron spectroscopy of trisubstituted benzenes: Dichloroiodobenzenes

    International Nuclear Information System (INIS)

    The electronic structure of isomeric dichloroiodobenzenes (C6H3ICl2) has been investigated by HeI/HeII photoelectron spectroscopy. The spectra were assigned by Green's functions calculations and comparison with the spectra of related dichlorobenzenes (C6H4Cl2). The careful analysis of ?-orbital and halogen lone pair ionization energies, enabled us to analyze substituent effects in detail, describing them in terms of resonance, inductive and spin-orbit coupling interactions. The use of several descriptors simultaneously, rather than a single one, appears to be necessary to unravel the effects in polysubstituted benzenes. Our method of analysis is capable of describing substituent effect in detail even in polysubstituted benzenes where kinetic or equilibrium methods become impractical

  14. Separation of benzene and 2H-substituted benzene via potassium reduction

    International Nuclear Information System (INIS)

    Perdeuteriated benzene can be partially separated from mixtures of perdeuteriated benzene and benzene simply by (1) reducing a mixture of C6H6 and C6D6 containing a molar deficient amount of 18-crown-6 (18C6) to the mixture with potassium metal and (2) distillation of the neutral benzenes from the metal-crown-anion radical complex, followed by (3) reoxidation of the anion radical back to the neutral benzenes. These isotopic enrichments are explained in terms of the less-than unity equilibrium constant for the electron transfer [K+(18C6)C6H6/sup /center dot/-/ + C6D6 = K+(18C6)C6D6/sup /center dot/-/ + C6H6]. In this way the differences in the physical properties of an anion radical and a neutral molecule are utilized to separate isotopic mixtures. The differences in the chemical properties can also be used to effect similar separations. This was demonstrated by adding water to a partially reduced mixture of naphthalene and perdeuterionaphthalene. Since the solution electron affinity of the isotopically light material is larger than that of the perdeuteriated material, the water addition results in the formation of dihydronaphthalene and dihydroperdeuterionaphthalene with the ratio [C10H10]/[C10D8H2] being greater than the ratio [C10H8]/[C10D8] in the original mixture

  15. Evaluation of occupational exposure to benzene by urinalysis.

    Science.gov (United States)

    Ghittori, S; Maestri, L; Fiorentino, M L; Imbriani, M

    1995-01-01

    Urinary phenol determinations have traditionally been used to monitor high levels of occupational benzene exposure. However, urinary phenol cannot be used to monitor low-level exposures. New biological indexes for exposure to low levels of benzene are thus needed. The aim of this study was to investigate the relations between exposure to benzene (A-benzene, ppm), as measured by personal air sampling, and the excretion of benzene (U-benzene, ng/l), trans,trans-muconic acid (MA, mg/g creatinine), and S-phenylmercapturic acid (PMA, micrograms/g creatinine) in urine. The subjects of the study were 145 workers exposed to benzene in a chemical plant. The geometric mean exposure level was 0.1 ppm (geometric standard deviation = 4.16). After logarithmic transformation of the data the following linear regressions were found: log (U-benzene, ng/l) = 0.681 log (A-benzene ppm) + 4.018; log (MA, mg/g creatinine) = 0.429 log (A-benzen ppm) - 0.304; and log (PMA, micrograms/g creatinine) = 0.712 log (A-benzene ppm) + 1.664. The correlation coefficients were, respectively, 0.66, 0.58, and 0.74. On the basis of the equations it was possible to establish tentative biological limit values corresponding to the respective occupational exposure limit values. In conclusion, the concentrations of benzene, mercapturic acid, and muconic acid in urine proved to be good parameters for monitoring low benzene exposure at the workplace. PMID:7591178

  16. Environmental exposure to benzene: an update.

    Science.gov (United States)

    Wallace, L

    1996-01-01

    During the 1990s, several large-scale studies of benzene concentrations in air, food, and blood have added to our knowledge of its environmental occurrence. In general, the new studies have confirmed the earlier findings of the U.S. Environmental Protection Agency Total Exposure Assessment Methodology (TEAM) studies and other large-scale studies in Germany and the Netherlands concerning the levels of exposure and major sources. For example, the new studies found that personal exposures exceeded indoor concentrations of benzene, which in turn exceeded outdoor concentrations. The new studies of food concentrations have confirmed earlier indications that food is not an important pathway for benzene exposure. The results of the National Health and Nutrition Examination Survey on blood levels in a nationwide sample of 883 persons are in good agreement with the concentrations in exhaled breath measured in about 800 persons a decade earlier in the TEAM studies. Major sources of exposure continue to be active and passive smoking, auto exhaust, and driving or riding in automobiles. New methods in breath and blood sampling and analysis offer opportunities to investigate short-term peak exposures and resulting body burden under almost any conceivable field conditions. PMID:9118882

  17. Accumulation of chlorinated benzenes in earthworms

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, W.N. [Patuxent Wildlife Research Center, Laurel, MD (United States)

    1996-12-31

    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. They probably entered the water as leachates from chemical waste dumps and as effluents from manufacturing. Hexachlorobenzene and pentachlorobenzene are commonly present in Herring gull (Larus argentatus) eggs from the Great Lakes, and some of the isomers of trichlorobenzene and tetrachlorobenzene are occasionally detected at low concentrations. Hexachlorobenzene, which was formerly used as a fungicide, has been the most thoroughly studied chlorinated benzene, and has been detected in many species. Its use as a fungicide in the United States was canceled in 1984. Since about 1975 hexachlorobenzene has been formed mainly in the production of chlorinated solvents. It is highly persistent in the environment and some species are poisoned by hexachlorobenzene at very low chronic dietary exposures. As little as 1 ppm in the diet of mink (Mustela vison) reduced the birth weights of young, and 5 ppm in the diet of Japanese quail (Coturnix coturnix japonica) caused slight liver damage. This paper describes a long-term (26 wk) experiment relating the concentrations of chlorinated benzenes in earthworms to length of exposure and three 8 wk experiments relating concentration to the concentration in soil the soil organic matter content, and the degree of chlorination. 20 refs., 3 figs., 1 tab.

  18. A pilot study on the stability of toluene in blood from workers

    Directory of Open Access Journals (Sweden)

    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 4°C. 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 4°C. Our data size is limited; however, it may be considered basic information for biological monitoring in medical examinations.

  19. Developmental neurotoxicity after toluene inhalation exposure in rats

    DEFF Research Database (Denmark)

    Hass, Ulla; Lund, SØren Peter

    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 TG for Developmental Neurotoxicity Study, i.e., physical development, reflex ontogeny, motor function, motor activity, sensory function, and learning and memory. The exposure did not cause maternal toxicity or decreased viability of the offspring. Lower birth weight, delayed ontogeny of reflexes, and increased motor activity in the open field was registered in the exposed offspring. Impaired cognitive function was revealed in the exposed female offspring at the age of 3.5 months, i.e., they used more time to locate the hidden platform in the Morris water maze after platform relocation. The difference 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.

  20. Benzylation of Toluene over Iron Modified Mesoporous Ceria

    Directory of Open Access Journals (Sweden)

    K.J. Rose Philo

    2012-12-01

    Full Text Available Green chemistry has been looked upon as a sustainable science which accomplishes both economical and environmental goals, simultaneously.With this objective, we developed an alternative process to obtain the industrially important benzyl aromatics by benzylation of aromatics using benzyl chloride, catalysed by mesoporous solid acid catalysts. In this work mesoporous ceria is prepared using neutral surfactant which helped the calcination possible at a lower temperature enabling a higher surface area. Mesoporous ceria modified with Fe can be successfully utilized for the selective benzylation of toluene to more desirable product methyl diphenyl methane with 100% conversion and selectivity in 2 hours using only 50mg of the catalyst under milder condition. The reusability, regenerability, high selectivity, 100% conversion, moderate reaction temperature and absence of solvent, etc. make these catalysts to be used in a truly heterogeneous manner and make the benzylation reaction an environment friendly one. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 30th June 2012; Revised: 7th November 2012; Accepted: 10th November 2012[How to Cite: K.J. Rose Philo, S. Sugunan. (2012. Benzylation of Toluene over Iron Modified Mesoporouxs Ceria. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 158-164. (doi:10.9767/bcrec.7.2.3759.158-164][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3759.158-164 ] | View in 

  1. Free radicals generated in yeast by the Salmonella test-negative carcinogens benzene, urethane, thiourea and auramine O.

    Science.gov (United States)

    Brennan, R J; Schiestl, R H

    1998-07-17

    A large fraction of carcinogens score negative in short-term genotoxicity assays such as the Salmonella reverse mutation (Ames) assay. More information is needed about the mechanism of action of such Salmonella-negative carcinogens. Many Salmonella-negative carcinogens induce deletions due to intrachromosomal recombination in Saccharomyces cerevisiae with an apparent threshold. We have previously shown that the Salmonella-negative carcinogens cadmium, aniline, chloroform and carbon tetrachloride generate free radical species in S. cerevisiae. We have further investigated the possible generation of intracellular free radical species by the diverse Salmonella-negative carcinogens benzene, urethane, thiourea and auramine O. The toxicity and recombinagenicity of thiourea and auramine O was reduced in the presence of the free radical scavenger N-acetyl cysteine. N-acetyl cysteine did not protect against toxicity or recombination induced by the Salmonella-positive carcinogens ethyl methane sulfonate, methyl methane sulfonate or nitroquinoline-N-oxide. A strain deficient in the enzyme superoxide dismutase, which catalyses the dismutation of superoxide anion radical, was hypersensitive to killing by benzene, urethane and thiourea. The sod- strain was only slightly more sensitive to the Salmonella-positive carcinogens. Intracellular oxidation of the free radical-sensitive reporter compound dichlorofluorescin diacetate was increased in yeast cultures exposed to benzene, urethane and auramine O; again, the Salmonella mutagens had no effect on oxidation of the dye. These data show that free radical species are produced in Saccharomyces cerevisiae following exposure to benzene, urethane, thiourea and auramine O, and suggest a possible role for oxidative stress is recombination induced by these carcinogens. PMID:9726007

  2. PREFRACTIONATION OF HIGH BENZENE PRECURSORS’ FEED FOR HYBRID REFORMER UNIT

    Directory of Open Access Journals (Sweden)

    K. Kirilov

    2008-03-01

    Full Text Available Benzene is toxic air pollutant and that’s why is set a constraint to 1% (v/v in gasoline. Refiners have to lower benzene in its gasoline pool components. High benzene contributors are reformate and FCC gasoline. Worldwide practice is to optimize the reformate benzene content. Some light crude oils, like Samgori from Georgia contain more fraction with boiling temperature interval from 60 to 85oC. This fraction is an indicator for benzene precursors content in gasoline. There is a possibility in LNB of prefractionation the reformer feed in columns K 105 from ADU and K1 from hydrotreating of catalytic reforming.A simulation was run with both aims: lowering benzene precursors and not to decrease reformer feed. The best solution is using K1 for its high potential reboiler’s duty.

  3. Use of Selective Inhibitors and Chromogenic Substrates to Differentiate Bacteria Based on Toluene Oxygenase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Keener, William Kelvin; Schaller, Kastli Dianne; Walton, Michelle Rene; Partin, Judy Kaye; Watwood, Mary Elizabeth; Smith, William Aaron; Chingenpeel, S. R.

    2001-09-01

    In whole-cell studies, two alkynes, 1-pentyne and phenylacetylene, were selective, irreversible inhibitors of monooxygenase enzymes in catabolic pathways that permit growth of bacteria on toluene. 1-Pentyne selectively inhibited growth of Burkholderia cepacia G4 (toluene 2-monooxygenase [T2MO] pathway) and B. pickettii PKO1 (toluene 3-monooxygenase [T3MO] pathway) on toluene, but did not inhibit growth of bacteria expressing other pathways. In further studies with strain G4, chromogenic transformation of a,a,a-Trifluoro-m-cresol (TFC) was irreversibly inhibited by 1-pentyne, but the presence of phenol prevented this inhibition. Transformation of catechol by G4 was unaffected by 1-pentyne. With respect to the various pathways and bacteria tested, phenylacetylene selectively inhibited growth of Pseudomonas mendocina KR1 (toluene 4-monooxygenase [T4MO] pathway) on toluene, but not on p-cresol. An Escherichia coli transformant expressing T4MO transformed indole or naphthalene in chromogenic reactions, but not after exposure to phenylacetylene. The naphthalene reaction remained diminished in phenylacetylene-treated cells relative to untreated cells after phenylacetylene was removed, indicating irreversible inhibition. These techniques were used to differentiate toluene-degrading isolates from an aquifer. Based on data generated with these indicators and inhibitors, along with results from Biolog analysis for sole carbon source oxidation, the groundwater isolates were assigned to eight separate groups, some of which apparently differ in their mode of toluene catabolism.

  4. Low-temperature anaerobic biological treatment of toluene-containing wastewater.

    Science.gov (United States)

    Enright, Anne-Marie; Collins, Gavin; O'Flaherty, Vincent

    2007-04-01

    Two expanded granular sludge bed-anaerobic filter (EGSB-AF) bioreactors, R1 and R2, were operated at 15 degrees C for the treatment of toluene-contaminated volatile fatty acid-based wastewater. The seed inoculum and the R1 reactor were unexposed to toluene, prior to and during the trial, respectively. Both reactors were operated at a hydraulic retention time of 24h at applied organic loading rates of 0.71-1.43kg chemical oxygen demand (COD)m(-3)d(-1). Toluene was supplemented to the R2 influent at concentrations of 5-104 mg toluenel(-1) (solubilised in ethanol). Bioreactor performance was evaluated by COD and toluene removal efficiency, and the methane content of biogas (%). Specific methanogenic activity and toxicity assays were employed to investigate the activity and toluene toxicity thresholds of key trophic groups, respectively, within the seed and reactor biomass samples. COD and toluene removal efficiencies of 70-90% and 55-99%, respectively, were achieved during the 630-d trial. Metabolic assays suggested that a psychrotolerant H(2)/CO(2)-utilizing methanogenic community developed in the toluene-degrading biomass. The results indicate the viability of low-temperature anaerobic digestion for the treatment of wastewater containing toluene. PMID:17306857

  5. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Science.gov (United States)

    2010-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... 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...

  6. Detection of Toluene Degradation in Bacteria Isolated from Oil Contaminated Soils

    International Nuclear Information System (INIS)

    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)

  7. Benzene exposure: An overview of monitoring methods and their findings

    OpenAIRE

    Weisel, Clifford P

    2010-01-01

    Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and occupational exposures. Inhalation is the most common exposure route but benzene rapidly penetrates the skin and can contaminant water and food resulting in dermal and ingestion exposures. While less toxic solvents have been substituted for benzene, it still is a component of petroleum products, including gasoline, and is a trac...

  8. The solubilities of benzene polycarboxylic acids in water

    Energy Technology Data Exchange (ETDEWEB)

    Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Manzurola, Emanuel [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Abo Balal, Nazmia [Negev Academic College of Engineering, Beer Sheva (Israel)

    2006-05-15

    The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities.

  9. The solubilities of benzene polycarboxylic acids in water

    International Nuclear Information System (INIS)

    The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities

  10. Highly selective GaN-nanowire/TiO2-nanocluster hybrid sensors for detection of benzene and related environment pollutants

    International Nuclear Information System (INIS)

    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 deg. 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.

  11. Highly selective GaN-nanowire/TiO2-nanocluster hybrid sensors for detection of benzene and related environment pollutants

    Science.gov (United States)

    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.

  12. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    Directory of Open Access Journals (Sweden)

    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.

  13. Impact of a new condensed toluene mechanism on air quality model predictions in the US

    Directory of Open Access Journals (Sweden)

    G. Sarwar

    2011-03-01

    Full Text Available A new condensed toluene mechanism is incorporated into the Community Multiscale Air Quality Modeling system. Model simulations are performed using the CB05 chemical mechanism containing the existing (base and the new toluene mechanism for the western and eastern US for a summer month. With current estimates of tropospheric emission burden, the new toluene mechanism increases monthly mean daily maximum 8-h ozone by 1.0–3.0 ppbv in Los Angeles, Portland, Seattle, Chicago, Cleveland, northeastern US, and Detroit compared to that with the base toluene chemistry. It reduces model mean bias for ozone at elevated observed ozone concentrations. While the new mechanism increases predicted ozone, it does not enhance ozone production efficiency. A sensitivity study suggests that it can further enhance ozone if elevated toluene emissions are present. While it increases in-cloud secondary organic aerosol substantially, its impact on total fine particle mass concentration is small.

  14. Going the distance with ethyl alcohol

    International Nuclear Information System (INIS)

    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

  15. Optical diagnostic method for benzene detection in air

    Science.gov (United States)

    Alnis, J.; Revalde, G.; Vrublevskis, A.; Gavare, Z.

    2014-10-01

    In this paper we show our first results of research for creation a detector for benzene vapor and possibly other volatile organic compounds detection in air based on Zeeman atomic absorption technique. First the detailed study of benzene absorption spectra with high resolution spectrometer Jobin-Yvon 1000M was done. The absorption spectra of benzene were registered in the spectral range from 200-900 nm. More detailed analysis was done for the 240 - 260 nm spectral range to test a possibility to detect benzene by means of emission line of 254 nm of mercury.

  16. Changes in sleep-waking rhythms of rats following a single injection of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Nakagagi, K.; Arito, H.; Tsuruta, H.

    1983-01-01

    The acute effects of toluene on sleep-waking rhythms were investigated in rats. In order to determine the characteristics of sleep-waking rhythms in rats quantitatively, polygraphic recordings of cortical EEG activity and neck EMG were made under a 12:12 light-dark schedule. Toluene was injected intraperitoneally at three dosages, i.e., 200, 400, and 600 mg/kg of body weight. The toluene concentration in the blood was determined in rats implanted with a jugular catheter to collect the blood. The circadian sleep-waking rhythms were still entrained to the environmental light-dark cycle following the administration of toluene. On the day of administration, wakefulness (W) increased immediately after toluene administration at the lower two doses, and an abnormal EEG pattern was observed, transiently at the highest dose. The initial increase in W at 200 and 400 mg/kg, and the appearance of the abnormal EEG pattern at 600 mg/kg were observed for 32, 79 and 83 min. after the administration of toluene, respectively. The toluene concentration in the blood of rats given 600 mg/kg was about 70 ..mu..g/ml when the abnormal EEG disappeared. Slow wave sleep (SWS) and paradoxical sleep (PS) increased during the period when blood toluene levels decreased. On the second day, when almost all of the toluene was eliminated from the blood, the lowest dose produced an increase in PS during the dark period, and the higher two doses produced a decrease in PS during the light period. At the highest dose, the amount of SES during the light period was still higher than control. Toluene-induced changes in the sleep-waking rhythms returned to the control by the third day.

  17. Isolation and characterization of Pseudomonas putida PpF1 mutants defective in the toluene dioxygenase enzyme system.

    OpenAIRE

    Finette, B A; V. Subramanian; Gibson, D. T.

    1984-01-01

    Pseudomonas putida PpF1 degraded toluene via a dihydrodiol pathway to tricarboxylic acid cycle intermediates. The initial reaction was catalyzed by a multicomponent enzyme, toluene dioxygenase, which oxidized toluene to (+)-cis-1(S),2(R)-dihydroxy-3-methylcyclohexa-3,5-diene (cis-toluene dihydrodiol). The enzyme consisted of three protein components: NADH-ferredoxintol oxidoreductase (reductasetol), ferredoxintol, and a terminal oxygenase which is an iron-sulfur protein (ISPtol). Mutants bloc...

  18. Changes in markers of oxidative stress and membrane properties in synaptosomes from rats exposed prenatally to toluene

    DEFF Research Database (Denmark)

    Edelfors, Sven; Hass, Ulla; Hougaard, Karin S.

    2002-01-01

    The present study was undertaken in order to investigate if toluene induced oxidative stress in brains from rats exposed prenatally to 1800 ppm toluene 6 hr/day at days 7-20 during the pregnancy. 35-42 days after birth the rats were killed and synaptosomal fractions were prepared for the experiments, Synaptosomes from rats exposed prenatally to toluene exhibited an increased level of oxidative stress when incubated with toluene in vitro compared to synaptosomes from unexposed offspring. Also the...

  19. Metatranscriptome of an Anaerobic Benzene-Degrading, Nitrate-Reducing Enrichment Culture Reveals Involvement of Carboxylation in Benzene Ring Activation

    OpenAIRE

    LUO, Fei; Gitiafroz, Roya; Devine, Cheryl E.; Gong, Yunchen; Hug, Laura A; Raskin, Lutgarde; Edwards, Elizabeth A.

    2014-01-01

    The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the different...

  20. Mathematical Modeling and Simulation of the Dehydrogenation of Ethyl Benzene to Form Styrene Using Steady-State Fixed Bed Reactor

    Directory of Open Access Journals (Sweden)

    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.

  1. Phase behavior of asphaltenes + polystyrene + toluene mixtures at 293 K

    Energy Technology Data Exchange (ETDEWEB)

    Khammar, Merouane; Shaw, John M. [Department of Chemical and Materials Engineering, University of Alberta, (Canada)], email: jmshaw@ualberta.ca

    2010-07-01

    This study provides an insight on studying the phase behavior of asphaltene and its importance in the petroleum industry. Phase behavior of an asphaltene, polystyrene, and toluene mixture at 293K was investigated in this work using a phased-array acoustic technique. This technique involved recording the speeds of sounds and attenuation spectra at 113 locations along the height of the test cell. The mixture separated into 2 liquid phases and depletion flocculation was believed to be the reason for this behavior. Moreover, attenuation profiles of the mixture were obtained and compared at the moment of mixing and at separation. When the 2 liquid phases were formed it was shown from the attenuation profile that the top liquid, later labeled as poor asphaltene, exhibited a lower attenuation and speed of sound than the bottom liquid, labeled as rich asphaltene. These results were later compared to those of a previous effort based on depletion flocculation theory, showing discrepancies in speeds of sound measurements.

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

    International Nuclear Information System (INIS)

    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)

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

    Directory of Open Access Journals (Sweden)

    Mello Ivana L.

    2006-01-01

    Full Text Available Viscometric measurements, in toluene solution at 30 ºC, were performed with high-cis polybutadiene synthesized by neodymium based catalyst. Six different equations were used to calculate intrinsic viscosities and viscosimetric constant values: Huggins, Kraemer, Martin and Schulz-Blaschke by graphic extrapolation, and Solomon-Ciuta, Deb-Chanterjee and again Schulz-Blaschke, through a single point determination. The molecular weight of the polymers was also determined applying Mark-Houwink-Sakurada equation using the values of intrinsic viscosity obtained by the six equations. The values of intrinsic viscosity and viscosity-average molecular weight obtained by the two methods were compared in order to verify the validity of the single point determination for high-cis polybutadiene.

  4. Gas phase toluene isopropylation over high silica mordenite

    Indian Academy of Sciences (India)

    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.

  5. Computational exploration of the mechanism of copper-catalyzed aromatic C-H bond amination of benzene via a nitrene insertion approach.

    Science.gov (United States)

    Hou, Kaipeng; Hrovat, David A; Bao, Xiaoguang

    2015-10-01

    The mechanism of aromatic C-H amination of benzene via a nitrene insertion approach catalyzed by the Tp(Br3)Cu(NCMe) complex was computationally investigated. The results of computational studies show that addition of the nitrene moiety of the Tp(Br3)Cu-nitrene intermediate to benzene, and therefore, to form an aziridine intermediate, is more favorable than the nitrene moiety induced hydrogen atom abstraction from a sp(2) C-H bond of benzene. Subsequently, the cleavage of a C-N bond of the aziridine intermediate followed by an H-atom transfer step might occur, due to the driving force of the rearomatization, to afford the desired aromatic C-H amination product. For toluene, computational results suggest that the benzylic C-H amination via hydrogen atom abstraction followed by radical rebound path is more favorable than the aromatic C-H amination via a nitrene addition path, which is in accord with experimental results. PMID:26343255

  6. Solid liquid interfacial free energies of benzene

    Science.gov (United States)

    Azreg-A?¨nou, M.

    2007-02-01

    In this work we determine for the range of melting temperatures 284.6?T?306.7 K, corresponding to equilibrium pressures 20.6?P?102.9 MPa, the benzene solid-liquid interfacial free energy by a cognitive approach including theoretical and experimental physics, mathematics, computer algebra (MATLAB), and some results from molecular dynamics computer simulations. From a theoretical and mathematical points of view, we deal with the elaboration of an analytical expression for the internal energy derived from a unified solid-liquid-vapor equation of state and with the elaboration of an existing statistical model for the entropy drop of the melt near the solid-liquid interface. From an experimental point of view, we will use our results obtained in collaboration with colleagues concerning the supercooled liquid benzene. Of particular interest for this work is the existing center-of-mass radial distribution function of benzene at 298 K obtained by computer simulation. Crystal-orientation-independent and minimum interfacial free energies are calculated and shown to increase slightly with the above temperatures. Both crystal-orientation-independent and minimum free energies agree with existing calculations and with rare existing experimental data. Taking into account the fact that the extent of supercooling is generally admitted as a constant, we determine the limits of supercooling by which we explore the behavior of the critical nucleus radius which is shown to decrease in terms of the above temperatures. The radius of the, and the number of molecules per, critical nucleus are shown to assume the average values of 20.2 A? and 175 with standard deviations of 0.16 Å and 4.5, respectively.

  7. Accumulation of chlorinated benzenes in earthworms

    Science.gov (United States)

    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 < 0.05), the decrease was minor. Hexachlorobenzene in 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 < 0.05). Concentrations of both trichlorobenzene and hexachlorobenzene in 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.

  8. 2,6-Bis(9-ethyl-9H-carbazolylmethylenecyclohexanone

    Directory of Open Access Journals (Sweden)

    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.

  9. 40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

    Science.gov (United States)

    2010-07-01

    ...benzene ether, polymer with substituted phenol (generic). 721.1580 Section 721...benzene ether, polymer with substituted phenol (generic). (a) Chemical substance...benzene ether, polymer with substituted phenol (PMN P-98-155) is subject to...

  10. Benzene synthesis using aluminosilicate catalysts for determining 14C activity by liquid scintillation method

    International Nuclear Information System (INIS)

    The basic characteristics are described of various aluminosilicate catalysts used for benzene synthesis. The methods of catalyst preparation and the methodology of benzene synthesis guaranteeing a 98% benzene yield are described. (author)

  11. Experimental Emulsified Diesel and Benzen Investigation

    Directory of Open Access Journals (Sweden)

    Suleiman Abu-Ein

    2010-05-01

    Full Text Available This study presents an experimental investigation of emulsified fuels as an operating material for vehicle engines. Water in fuel blends is still relatively unknown and unaccepted by the majority of people. Introducing water into the combustion chamber has been around for more than one time, through water injection systems and emulsification of water into fuel. Adding water to fules will reduce bad emissions of the vehicles. It is found that brake power, engine power and also the engine torque have been improved with the emulsified fuels for both diesel and benzen till 25% water percentage addition.

  12. The gelation of oil using ethyl cellulose.

    Science.gov (United States)

    Davidovich-Pinhas, M; Barbut, S; Marangoni, A G

    2015-03-01

    The characterization of the thermo-gelation mechanism and properties of ethyl cellulose/canola oil oleogels was performed using rheology and thermal analysis. Thermal analysis detected no evidence for thermal transitions contributed to secondary conformational changes, suggesting a gelation mechanism that does not involve secondary ordered structure formation. Rheological analysis demonstrated a relationship between the polymer molecular weight and the final gel strength, the cross-over behavior as well as the gel point temperature. Increasing polymer molecular weight led to an increase in final gel strength, the modulus at cross-over, and the gel point temperature. Cooling/heating rates affect gel modulus only for the low molecular weight samples. A decrease in gel strength with increasing cooling rate was detected. The cross-over temperature was not affected by the cooling/heating rates. Cooling rate also affected the gelation setting time where slow cooling rates produced a stable gel faster. PMID:25498711

  13. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    International Nuclear Information System (INIS)

    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.

  14. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Ming-Huan [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Institute of Neuroscience, National Changchi University, Taipei, Taiwan (China); Chung, Shiang-Sheng [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Department of Pharmacy, Yuli Veterans Hospital, Hualien, Taiwan (China); Stoker, Astrid K.; Markou, Athina [Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA (United States); Chen, Hwei-Hsien, E-mail: hwei@nhri.org.tw [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Division of Mental Health and Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan (China)

    2012-12-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-D-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperature, and intracranial self-stimulation (ICSS) thresholds in mice. Additionally, the effects of sarcosine on the behavioral and physiological effects induced by toluene were evaluated. Sarcosine may reverse toluene-induced behavioral manifestations by acting as an NMDA receptor co-agonist and by inhibiting the effects of the type I glycine transporter (GlyT1). Mice were treated with toluene alone or combined with sarcosine pretreatment and assessed for rotarod performance, object recognition memory, rectal temperature, and ICSS thresholds. Toluene dose-dependently induced motor incoordination, recognition memory impairment, and hypothermia and lowered ICSS thresholds. Sarcosine pretreatment reversed toluene-induced changes in rotarod performance, novel object recognition, and rectal temperature but not ICSS thresholds. These findings suggest that the sarcosine-induced potentiation of NMDA receptors may reverse motor incoordination, memory impairment, and hypothermia but not the enhancement of brain stimulation reward function associated with toluene exposure. Sarcosine may be a promising compound to prevent acute toluene intoxications by occupational or intentional exposure. -- Highlights: ? Toluene induces impairments in Rotarod test and novel object recognition test. ? Toluene lowers rectal temperature and ICSS thresholds in mice. ? Sarcosine reverses toluene-induced changes in motor, memory and body temperature. ? Sarcosine pretreatment does not affect toluene-induced reward enhancement.

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

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1992-01-01

    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, they are primarily responsible for the biofilm growth. The active biomass decays into biodegradable and ``inert'' dead biomass which is hydrolyzed into soluble products at two different rates. These products are partly degradable by the biomass and constitute the endogenous respiration. The dynamic growth phase with toluene degradation was successfully modelled as well as the decay phase when toluene addition was turnedoff. In addition to this, modelling of toluene removal and oxygen consumption versus toluene concentration in the reactor was performed. This required consideration of inhibition of substrate degradation due to the combination of high oxygen and toluene concentrations.

  16. Optimizing nutrient supply in a rotatory-switching biofilter for toluene vapor treatment.

    Science.gov (United States)

    Morita, Yasutaka; Okunishi, Suguru; Higuchi, Takashi; Nakajima, Jun

    2012-04-01

    The influence of nutrient conditions on the degradation of toluene vapor in a rotatory-switching biofilter (RSB) was investigated. The biofilter consists of four segments connected in series, each with a packing layer made of polyvinyl formal. The influent airstreams including toluene vapors were passed through segments 1-3 as up-flow with a toluene concentration of 0.9-1.2 g m(-3) and with an empty-bed retention time of 26-52 sec. Nutrient solutions were fed to all packed segments once a day by means of immersion. The nutrient solution was used repeatedly and replenished by the addition of (NH4)2SO4. The result at 155 days showed nitrogen depletion was particularly obvious and the lack of nitrogen affected toluene removal. By adding 161 g of nitrogen solution per volumetric cubic meter of reactor, toluene removal efficiency was immediately increased to greater than 99%. With long-term biofilter operation, 21%-32% of ammonium was utilized for nitrification because of the growth of nitrifying bacteria such as Nitrosomonas sp. Based on the carbon-nitrogen balance, the daily nitrogen demand for toluene removal was estimated 2.1 g day(-1) at a toluene load of 70 g m(-3) hr(-1). PMID:22616287

  17. Liver function in patients exposed to a toluene in a hydrocarbon processing plant

    International Nuclear Information System (INIS)

    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

  18. Response of solvent-exposed printers and unexposed controls to six-hour toluene exposure

    DEFF Research Database (Denmark)

    Bælum, Jesper; Andersen, I B

    1985-01-01

    The acute effects of toluene were studied in 43 male printers and 43 control subjects matched according to sex, age, educational level, and smoking habits. The mean age of the subjects was 36 (range 29-50) years. The printers had been exposed to solvents for 9 to 25 years during employment at flexo and rotogravure printing plants, while the controls had no history of solvent exposure. Each subject was exposed once in a climate chamber to either 100 ppm of toluene or clean air for 6.5 h preceded by a 1-h acclimatization period. The effects of toluene were measured from subjective votes with linear analogue rating scales on 16 items, and on the performance of 10 different tests measuring psychomotor skills, perceptual skills, and vigilance. Exposure to 100 ppm of toluene compared with exposure to clean air caused discomfort with complaints of low air quality, strong odor, fatigue, sleepiness, a feeling of intoxication, and irritation of the eyes, nose and throat. Furthermore, the subjects exposed to toluene showed decreased manual dexterity, decreased color discrimination, and decreased accuracy in visual perception. There was no significant difference in the effects of toluene on printers compared to those of toluene on controls, but tendencies toward a greater sensitivity were seen for the printers in two tests.

  19. 2H NMR study of dynamics of benzene-d6 interacting with humic and fulvic acids.

    Science.gov (United States)

    Eastman, Margaret A; Brothers, Lucinda A; Nanny, Mark A

    2011-05-01

    Samples of three humic acids and one fulvic acid with 1% loading of benzene-d(6) in sealed glass tubes have been studied with solid-state deuterium quadrupole-echo nuclear magnetic resonance spectroscopy. Calculated spectra combining three motional models, two isotropic models and a third more restricted small-angle wobble (SAW) motional model, are fit to the experimental spectra. One isotropic motion (ISO(v)) is assigned to vaporous benzene-d(6) due to the small line width, short T(1), and the loss of this component by about -25 °C when the temperature is lowered. The remaining two motional components, ISO(s) and SAW, are sorbed by the humic or fulvic acid. Benzene-d(6) slowly interacts with the humic substances, progressively filling SAW sites as ISO(s) motion diminishes. Both the sorption and increase in percentage of SAW motion are for the most part complete within 200 days but continue to a lesser extent over a period of a few years. For the SAW motion there are at least two and most likely a series of T(1) values, indicating more than one adsorption environment. Enthalpies of sorption, obtained from application of the van't Hoff equation to the percentages of the different motional models derived from a series of variable temperature spectra, are comparable in magnitude to the enthalpy of vaporization of benzene. In Leonardite humic acid, ?H and ?S for the ISO(s) to SAW transition change from positive to negative values with age, implying a transition in the driving force from an entropic effect associated with expansion and deformation in the molecular structure of the humic substance to accommodate benzene-d(6) to an enthalpic effect of strong benzene-d(6)-humic substance interactions. In contrast, at advanced ages, Suwannee River humic and fulvic acids have small positive or near zero ?H and positive ?S for the ISO(s) to SAW transition. PMID:21456559

  20. The excited state antiaromatic benzene ring: a molecular Mr Hyde?

    Science.gov (United States)

    Papadakis, Raffaello; Ottosson, Henrik

    2015-09-21

    The antiaromatic character of benzene in its first ??* excited triplet state (T1) was deduced more than four decades ago by Baird using perturbation molecular orbital (PMO) theory [J. Am. Chem. Soc. 1972, 94, 4941], and since then it has been confirmed through a range of high-level quantum chemical calculations. With focus on benzene we now first review theoretical and computational studies that examine and confirm Baird's rule on reversal in the electron count for aromaticity and antiaromaticity of annulenes in their lowest triplet states as compared to Hückel's rule for the ground state (S0). We also note that the rule according to quantum chemical calculations can be extended to the lowest singlet excited state (S1) of benzene. Importantly, Baird, as well as Aihara [Bull. Chem. Soc. Jpn. 1978, 51, 1788], early put forth that the destabilization and excited state antiaromaticity of the benzene ring should be reflected in its photochemical reactivity, yet, today these conclusions are often overlooked. Thus, in the second part of the article we review photochemical reactions of a series of benzene derivatives that to various extents should stem from the excited state antiaromatic character of the benzene ring. We argue that benzene can be viewed as a molecular "Dr Jekyll and Mr Hyde" with its largely unknown excited state antiaromaticity representing its "Mr Hyde" character. The recognition of the "Jekyll and Hyde" split personality feature of the benzene ring can likely be useful in a range of different areas. PMID:25960203

  1. Excess volumes in the solutions benzene-H6/benzene-D6, cyclohexane-H12/benzene-H6, cyclohexane-H12/benzene-D6, and benzene-H6/benzene-D6/H2O

    International Nuclear Information System (INIS)

    Excess volumes are reported for the title solutions across the entire concentration range at 25 and 400C. For the solution of isotopic isomers, C6H6/C6D6, the excess volume shows a complicated concentration dependence with a minimum of about -6 X 10-9 m3/mol near X/sub C6H6/ = 0.33 and a maximum of about 2 X 10-9 m3/mol near X/sub C6H6/ = 0.8 (250C). The effect is sensitive to trace water content. For benzene/cyclohexane solutions the volumetric isotope effects display simpler concentration dependences. Thus, the difference, V/sup E//sub C6H6///sub C6H12/ - V/sup E//sub C6D6///sub C6H12/, within experimental error shows simple minima at X/sub benzene/ = 0.5 of about -7 X 10-9 (250C) and -12 X 10-9 (450C) m3/mol. After comparing the present results for C6H6/C6H12 solutions with those of previous workers, we discuss isotope effects in terms of the theory of isotope effects on the properties of condensed phases

  2. Identification of a Toluene-Degrading Bacterium from a Soil Sample through H218O DNA Stable Isotope Probing ?†

    OpenAIRE

    Woods, Angela; Watwood, Maribeth; Schwartz, Egbert

    2011-01-01

    DNA stable isotope probing (DNA-SIP) with H218O was used to identify a toluene-degrading bacterium in soil amended with 48 ppm toluene. After quantification of toluene degradation rates in soil, DNA was extracted from soil incubated with H218O, H216O, H216O and 48 ppm toluene, or H218O and 48 ppm toluene. A single DNA band formed along a cesium chloride gradient after isopycnic centrifugation of extracts from soils incubated with H216O. With extracts from soils to which only H218O was added, ...

  3. A determinação colorimétrica de vapôres de benzeno no ar The colorimetric determination of benzene vapors in air

    Directory of Open Access Journals (Sweden)

    Herbert M. A. Stettiner

    1970-06-01

    Full Text Available Estudou-se um método simples para a determinação de pequenas quantidades de vapôres de benzeno no ar, aplicável em presença de seus homólogos. A interferência dos homólogos é eliminada destruindo seus nitrocompostos segundo BAERNSTEIN¹ (1943 pela oxidação com ácido crômico. Êste procedimento é combinado com o de DOLIN2,3 (1943, 1947 que isola o m-dinitrobenzeno pela extração com éter etílico, usando o extrato etéreo para a revelação da côr 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 BAERNSTEIN¹ (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.

  4. Inhaled toluene produces pentobarbital-like discriminative stimulus effects in mice

    Energy Technology Data Exchange (ETDEWEB)

    Rees, D.C.; Coggeshall, E.; Balster, R.L.

    1985-10-07

    The abuse of volatile solvents may be due to their ability to produce an intoxication similar to that produced by classical central nervous system depressants such as the barbiturates and ethanol. To evaluate this hypothesis, mice were trained to discriminate pentobarbital from saline injections in a two-lever operant task. Stimulus generalization was examined following 20-min inhalation exposures to toluene (300-5400 ppm). In 8 of 10 subjects, pentobarbital-lever responding occurred following toluene exposure indicating an overlap in the discriminative stimulus properties of toluene and pentobarbital.

  5. Toluene in alveolar air during controlled exposure to constant and to varying concentrations

    DEFF Research Database (Denmark)

    Bælum, Jesper

    1990-01-01

    The concentration of toluene in the alveolar air was measured in 20 males and 17 females exposed for 7 h either to a constant exposure to 100 ppm toluene or to a varying exposure with the same time-weighted average, but with peaks of 300 ppm every 30 min. Both exposure schedules included 50 to 100 W exercise in three 15-min periods. Repetitive measurements of the toluene concentrations in the alveolar air were made in two 30-min periods, one at rest and one including work. At rest the alveolar c...

  6. Biodegradation of trichloroethylene and toluene by indigenous microbial populations in soil.

    OpenAIRE

    Fan, S; Scow, K.M.

    1993-01-01

    The biodegradation of trichloroethylene (TCE) and toluene, incubated separately and in combination, by indigenous microbial populations was measured in three unsaturated soils incubated under aerobic conditions. Sorption and desorption of TCE (0.1 to 10 micrograms ml-1) and toluene (1.0 to 20 micrograms ml-1) were measured in two soils and followed a reversible linear isotherm. At a concentration of 1 micrograms ml-1, TCE was not degraded in the absence of toluene in any of the soils. In comb...

  7. Comparative study of free and immobilized lipase from Bacillus aerius and its application in synthesis of ethyl ferulate.

    Science.gov (United States)

    Saun, Nitin Kumar; Narwal, Sunil Kumar; Dogra, Priyanka; Chauhan, Ghanshyam Singh; Gupta, Reena

    2014-01-01

    In the present study, a purified lipase from Bacillus aerius immobilized on celite matrix was used for synthesis of ethyl ferulate. The celite-bound lipase exposed to glutaraldehyde showed 90.02% binding efficiency. It took two hours to bind maximally onto the support. The pH and temperature optima of the immobilized lipase were same as those of free enzyme i.e 9.5 and 55°C. Among different substrates both free and immobilized lipase showed maximum affinity towards p-nitrophenyl palmitate (p-NPP). The lipase activity was found to be stimulated in the presence of Mg(2+) in case of free enzyme while Zn(2+) and Fe(3+) showed stimulatory effect on immobilized lipase whereas salt ions as well as chelating agents inhibited activity of both free and immobilized lipase. Maximum enzyme activity was observed in n-hexane as organic solvent followed by n-heptane for both free and immobilized lipase, however CCl4, acetone and benzene inhibited the enzyme activity. Moreover, all the selected detergents (SDS, Triton X-100, Tween 80 and Tween 20) had an inhibitory effect on both free and immobilized enzyme activity. The celite bound lipase (1.5%) efficiently performed maximum esterification (2.51 moles/l) of ethanol and ferulic acid (100 mM each, at a molar ratio of 1:3) when incubated at 55°C for 48 h resulting in the formation of ester ethyl ferulate. PMID:25099909

  8. Biodegradation of pyrazosulfuron-ethyl by Acinetobacter sp. CW17.

    Science.gov (United States)

    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

  9. Interfacial properties of asphaltenes at toluene-water interfaces.

    Science.gov (United States)

    Zarkar, Sharli; Pauchard, Vincent; Farooq, Umer; Couzis, Alexander; Banerjee, Sanjoy

    2015-05-01

    Asphaltenes are "n-alkane insoluble" species in crude oil that stabilize water-in-oil emulsions. To understand asphaltene adsorption mechanisms at oil-water interfaces and coalescence blockage, we first studied the behavior in aliphatic oil-water systems in which asphaltenes are almost insoluble. They adsorbed as monomers, giving a unique master curve relating interfacial tension (IFT) to interfacial coverage through a Langmuir equation of state (EoS). The long-time surface coverage was independent of asphaltene bulk concentration and asymptotically approached the 2-D packing limit for polydisperse disks. On coalescence, the surface coverage exceeded the 2-D limit and the asphaltene film appeared to become solidlike, apparently undergoing a transition to a soft glassy material and blocking further coalescence. However, real systems consist of mixtures of aliphatic and aromatic components in which asphaltenes may be quite soluble. To understand solubility effects, we focus here on how the increased bulk solubility of asphaltenes affects their interfacial properties in comparison to aliphatic oil-water systems. Unlike the "almost irreversible" adsorption of asphaltenes where the asymptotic interfacial coverage was independent of the bulk concentration, an equilibrium surface pressure, dependent on bulk concentration, was obtained for toluene-water systems because of adsorption being balanced by desorption. The equilibrium surface coverage could be obtained from the short- and long-term Ward-Tordai approximations. The behavior of the equilibrium surface pressure with the equilibrium surface coverage was then derived. These data for various asphaltene concentrations were used to determine the EoS, which for toluene-water could also be fitted by the Langmuir EoS with ?? = 3.3 molecule/nm(2), the same value as that found for these asphaltenes in aliphatic media. Asphaltene solubility in the bulk phase only appears to affect the adsorption isotherm but not the EoS. Further support for these observations is provided by dilatational rheology experiments for the EoS and contraction experiments in which desorption to the equilibrium surface pressure was observed. PMID:25865629

  10. (1R*,21S*,22R*,24S*)-Methyl ethyl 2-[23-hy­droxy-22,24-diphenyl-8,11,14-trioxa-25-aza­tetra­cyclo­[19.3.1.02,7.015,20]penta­cosa-2,4,6,15(20),16,18-hexaen-25-yl]but-2-enedioate

    OpenAIRE

    Truong Hong Hieu; Le Tuan Anh; Soldatenkov, Anatoly T.; Gorchakova, Olga S.; Khrustalev, Victor N.

    2013-01-01

    The title compound, C40H41NO8, is a product of the reduction of the cyclic carbonyl group of the ?-piperidone subunit of the aza-14-crown-4 ether with subsequent re-esterification of its dimethyl butenoate substituent into a monoethyl monomethyl group. The azacrown macrocycle exhibits a bowl conformation with a dihedral angle of 70.82?(5)° between the benzene rings fused to it. The piperidine ring adopts a chair conformation and the methyl ethyl ethylenedicarboxylate fragment ...

  11. Breakthrough of toluene vapours in granular activated carbon filled packed bed reactor

    International Nuclear Information System (INIS)

    The objective of this research was to determine the toluene removal efficiency and breakthrough time using commercially available coconut shell-based granular activated carbon in packed bed reactor. To study the effect of toluene removal and break point time of the granular activated carbon (GAC), the parameters studied were bed lengths (2, 3, and 4 cm), concentrations (5, 10, and 15 mg l-1) and flow rates (20, 40, and 60 ml/min). The maximum percentage removal of 90% was achieved and the maximum carbon capacity for 5 mg l-1 of toluene, 60 ml/min flow rate and 3 cm bed length shows 607.14 mg/g. The results of dynamic adsorption in a packed bed were consistent with those of equilibrium adsorption by gravimetric method. The breakthrough time and quantity shows that GAC with appropriate surface area can be utilized for air cleaning filters. The result shows that the physisorption plays main role in toluene removal.

  12. Transient pressure induced by laser ablation of toluene, a highly laser-absorbing liquid

    Science.gov (United States)

    Kawaguchi, Y.; Ding, X.; Narazaki, A.; Sato, T.; Niino, H.

    2005-02-01

    Transient processes of laser ablation of a highly laser-absorbing liquid, toluene, were investigated by directly measuring (by using a fast-response pressure gauge) the transient pressure caused by toluene ablation under KrF laser irradiation . The results were compared with time-resolved images . The peak pressure P due to a shock wave decreased slowly with increasing distance d for d=100 1000 ?m:P?d-0.33. By extrapolating P to d=8.9 ?m, the optical penetration depth of toluene at ?=248 nm, the estimated initial pressure due to toluene ablation was 65 MPa at 1.0 J cm-2 pulse-1. The estimated initial pressure increased linearly with the fluence. These results help clarify the mechanism of laser-induced backside wet etching.

  13. Radical production in the radiolysis of benzene

    International Nuclear Information System (INIS)

    Complete text of publication follows. Benzene is the prototypical aromatic compound and yet the radiation chemistry of the radicals formed in its radiolysis is not well understood. Temporal information on the yield of phenyl radical, the major radical produced in the radiolysis, is important for understanding the radiation chemistry of many other types of aromatic compounds including some polymers. The effects of track structure on the production of phenyl radicals have been examined using iodine-scavenging techniques. The variation of the yields of iodobenzene and the other major molecular products such as biphenyl as a function of iodine concentration gives a good indication of the competition kinetics occurring in particle tracks. Experimental results of the scavenger experiments will be shown and their implications in the radiolysis of condensed hydrocarbons will be discussed

  14. Mass-spectral isotope effects in the metastable transition of benzene and perdeuterio benzene

    International Nuclear Information System (INIS)

    The abundances of C6H5+, C6H4sup(+.), C4X4sup(+.), and C3X3+ (X=H, D) fragments occurring in the metastable transition of benzene and perdeuterio benzene have been measured by means of electron-impact ionization. The isotope effects on the relative intensities were reproduced by the simple model calculation on the basis of the RRKM theory. The vibrational frequencies of the transition states for the deuteriated and the nondeuteriated were obtained by a vibrational analysis for the assumed geometries and force fields. The transition states for the C6H5+ and C6H4sup(+.) channels preferred a benzene structure while those for the C4H4sup(+.) and C3H3+ has a propargyl-cyclopropene structure. The calculated decay rates for the C6H5+, C4H4sup(+.), and C3H3+ fragmentation were compared with those of the photoion photoelectron coincidence (PIPECO) results. (author)

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

    Scientific Electronic Library Online (English)

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

    2006-02-01

    Full Text Available Medidas viscosimétricas, em solução de tolueno a 30 °C, foram realizadas com polibutadieno alto-cis sintetizado com catalisadores à base de neodímio. Seis diferentes equações foram usadas para calcular as viscosidades intrínsecas e as constantes viscosimétricas: Huggins, Kraemer, Martin e Schulz-Bla [...] schke por extrapolação gráfica e Solomon-Ciuta, Deb-Chanterjee e novamente Schulz-Blaschke, por medida de único ponto. O peso molecular dos polímeros foi determinado aplicando-se a equação de Mark-Houwink-Sakurada, utilizando-se para isso, os valores de viscosidade intrínseca obtidos pelas seis equações. Os valores de viscosidade intrínseca e de peso molecular viscosimétrico médio foram comparados a fim de verificar a validade da determinação por um único ponto. Abstract in english Viscometric measurements, in toluene solution at 30 ºC, were performed with high-cis polybutadiene synthesized by neodymium based catalyst. Six different equations were used to calculate intrinsic viscosities and viscosimetric constant values: Huggins, Kraemer, Martin and Schulz-Blaschke by graphic [...] extrapolation, and Solomon-Ciuta, Deb-Chanterjee and again Schulz-Blaschke, through a single point determination. The molecular weight of the polymers was also determined applying Mark-Houwink-Sakurada equation using the values of intrinsic viscosity obtained by the six equations. The values of intrinsic viscosity and viscosity-average molecular weight obtained by the two methods were compared in order to verify the validity of the single point determination for high-cis polybutadiene.

  16. Sedimentation of asphaltenes dissolved in toluene using ultracentrifugation technique

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, R.; Chong, P. [Alberta Research Council, Edmonton, AB (Canada); Mostowfi, F. [Schlumberger DBR Technology Center, Edmonton, AB (Canada); Mullins, O. [Schlumberger Doll Research Center, Cambridge, MA (United States)

    2008-07-01

    Asphaltenes are known to precipitate from an oil formation under normal gravity. In this study, sedimentation experiments were carried out on dilute solutions of asphaltenes in toluene using an ultracentrifuge. The concentration of asphaltenes in solution was kept low enough so that the size of asphaltene aggregates would remain small. Near infrared spectrometry was used to monitor the concentration gradient of asphaltenes in the centrifuge tube at 3 different centrifugation periods, notably 7, 17 and 30 days. The total liquid sample recovered in every case contained about 75 per cent of the initially added asphaltenes. The dissolved hydrocarbons that settled to the bottom of the tube were ellipsoid. The remaining asphaltenes were molecularly dispersed and less than 1.2 nm in diameter and there is no settling after 30 days. The study showed that the role of ultra-fine organic solids in sedimentation of the asphaltenes must be taken into account. Asphaltenes adsorb on minerals such as kaolinite. The association of nano-sized asphaltenes with micron-sized solids could lead to rapid settling. An alternative explanation of the role of fine solids in sedimentation is that of increasing aggregation and settling due to the concentration gradient created in the settling field. As settling proceeds, aggregates of certain size begin to settle and increase in concentration towards the bottom of the tube from low gravity field to high gravity field.

  17. Transport and biodegradation of benzene in the saturated groundwater layer

    Directory of Open Access Journals (Sweden)

    Khongnakorn, W.

    2004-11-01

    Full Text Available The objective of this study was to investigate the biotic and abiotic processes that affected benzene transportation in the saturated groundwater layer. The study was performed in the laboratory using synthetic groundwater and soil sample from Maptaput Industrial Estate, Rayong. This study was divided into 3 parts; batch test, column test and computer modeling. The biotic, biodegradation, and the abiotic processes were studied in the batch system. The column experiment was performed to investigate the transport behavior of benzene. The computer program, CXTFIT, with parameters acquired from batch and column experiments was used to simulate the benzene transport behavior. It was found that benzene adsorption followed the linear adsorption isotherm with its coefficient (Kd of 0.544 cm3/g and the retardation factor of 5.43. The biodegradation rate could be estimated using the firstorder biodegradation rate equation with the degradation rate of 0.0009- 0.0092 per day. The dispersion coefficient estimated from column experiments was 0.0102 cm2/s. The results from computer simulation did not fit the experimental data well. It can be concluded that the transport of benzene was a non-equilibrium transport. It was also found that biodegradation of benzene had significant effect on benzene transportation in saturated groundwater. The simulated transport with biodegradation process fitted the data fairly.

  18. Combined effects of radiation and benzene in mice

    International Nuclear Information System (INIS)

    This study describes the combined effects of benzene and x-radiation on lethality and erythropoiesis. Since both benzene and irradiation are associated with similar toxic and lethal effects evidenced in the bone marrow of the recipient, this is a study of their interaction. It can be postulated that the combination of the two would be more toxic than either acting alone. However, because of benzene's metabolic degradation products and its unique tissue distribution, one could also expect that benzene might protect against radiation damage. This later hypothesis comes from the fact the phenols are produced as a consequence of the metabolism of benzene. These phenols can act as radical scavengers or as mitotic poisons; both mechanisms are known to be effective as radiation protectors. These experiments were designed to determine whether low dosages of benzene protect or are additive to the harmful effects of radiation.ults show that certain levels of benzene have protective effects on the host, depending on the amount and the time given prior to radiation

  19. Anaerobic Mineralization of Toluene by Enriched Sediments with Quinones and Humus as Terminal Electron Acceptors

    OpenAIRE

    Cervantes, F. J.; Dijksma, W.; Duong-Dac, T.; IVANOVA, A.; Lettinga, G.; J.A. Field

    2001-01-01

    The anaerobic microbial oxidation of toluene to CO2 coupled to humus respiration was demonstrated by use of enriched anaerobic sediments from the Amsterdam petroleum harbor (APH) and the Rhine River. Both highly purified soil humic acids (HPSHA) and the humic quinone moiety model compound anthraquinone-2,6-disulfonate (AQDS) were utilized as terminal electron acceptors. After 2 weeks of incubation, 50 and 85 percent added uniformly labeled [13C]toluene were recovered as 13CO2 in HPSHA- and AQ...

  20. Psychological Autopsy and Necropsy of an Unusual Case of Suicide by Intravenous Toluene

    OpenAIRE

    Kulkarni, Ranganath R.; Hemanth Kumar, RG; Kulkarni, Pratibha R.; Kotabagi, Raghavendra B.

    2015-01-01

    Toluene (methylbenzene; volatile hydrocarbon) is an industrial solvent that causes major injury to the lungs; the organ being the first capillary bed encountered. We report an unusual case of suicide by a 24-year-old male, paramedical professional, with fatal outcome within 16 h of intentional, intravenous self-administration of toluene, with clinical presentation of acute respiratory distress syndrome. Psychological autopsy revealed severe depressive disorder and solvent (inhalant) abuse, wi...

  1. Skin prick test results and prevalence of allergic symptoms in workers exposed to toluene

    OpenAIRE

    KARABULUT, ?smail; PINAR, Tevfik; KARABULUT, Hayriye; DEM?R, Melike; KARADEN?Z, Gülistan; KARA?EN, R?za Murat

    2012-01-01

    To determine the distribution of allergens and allergic symptoms according to occupation groups in those who were exposed to toluene and presented with allergic rhinitis symptoms. Materials and methods: Of the 2005 patients who were administered an allergy test with the prediagnosis of allergic rhinitis, the files of 138 patients who were exposed to toluene were analyzed retrospectively. Results: The mean age of the patients was 35 ± 10 years. Distributions of symptoms and allergens of 5...

  2. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    OpenAIRE

    Rajagopal K.; Silva S. M. C.

    2004-01-01

    The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10...

  3. Friedel-Crafts Alkylation of Toluene as a Parallel Reaction in Propylene Dimerization Catalyzed by Nickel ?-Diimine Complex/EASC in Homogeneous Phase

    Scientific Electronic Library Online (English)

    Isabel, Vicente; Katia, Bernardo-Gusmão; Michèle O. de, Souza; Roberto F. de, Souza.

    2014-12-01

    Full Text Available A oligomerização do propeno foi realizada utilizando o complexo dibromo-bis(N,N'- difenilpentano-2,4-diimina)niquel(II) como precursor catalítico combinado ao sesquicloreto de etilalumínio (Al2Et3Cl3, EASC) como co-catalisador. A 10 ºC, [...] usando o tolueno como solvente, altas frequências de rotação foram obtidas (até 57000 h–1) com alta seletividade em produtos C6 (até > 99%) e seletividade moderada em C6 linear (até 29%). Observou-se que nas condições experimentais empregadas o propeno reagiu com tolueno por reação de Friedel-Crafts. O aumento da concentração de precursor catalítico, mantendo constante a relação precursor/co-catalisador, teve por efeito de aumentar a selectividade para os produtos de oligomerização em relação aos produtos de alquilação por reação de Friedel-Crafts. Abstract in english Propylene oligomerization was performed using dibromo-bis(N,N'-diphenylpentane-2,4- diimine)nickel(II) complex as catalytic precursor combined with ethyl aluminum sesquichloride (Al2Et3Cl3, EASC) as co-catalyst. At 10 ºC, using toluene a [...] s solvent, high turnover frequencies (up to 57,000 h–1) with high selectivities to C6 products (up to > 99%) and moderate linear C6 selectivity (up to 29%) were obtained. Under our reaction conditions propylene reacted with toluene through Friedel-Crafts reaction. Increasing the concentration of catalyst precursor keeping the nickel complex/co-catalyst ratio constant increased the selectivity of the oligomerization products vs. Friedel-Craft products.

  4. Uptake of toluene and ethylbenzene by plants: removal of volatile indoor air contaminants.

    Science.gov (United States)

    Sriprapat, Wararat; Suksabye, Parinda; Areephak, Sirintip; Klantup, Polawat; Waraha, Atcharaphan; Sawattan, Anuchit; Thiravetyan, Paitip

    2014-04-01

    Air borne uptake of toluene and ethylbenzene by twelve plant species was examined. Of the twelve plant species examined, the highest toluene removal was found in Sansevieria trifasciata, while the ethylbenzene removal from air was with Chlorophytum comosum. Toluene and ethylbenzene can penetrate the plant?s cuticle. However, the removal rates do not appear to be correlated with numbers of stomata per plant. It was found that wax of S. trifasciata and Sansevieria hyacinthoides had greater absorption of toluene and ethylbenzene, and it contained high hexadecanoic acid. Hexadecanoic acid might be involved in toluene and ethylbenzene adsorption by cuticles wax of plants. Chlorophyll fluorescence analysis or the potential quantum yield of PSII (Fv/Fm) in toluene exposed plants showed no significant differences between the control and the treated plants, whereas plants exposed to ethylbenzene showed significant differences or those parameters, specifically in Dracaena deremensis (Lemon lime), Dracaena sanderiana, Kalanchoe blossfeldiana, and Cordyline fruticosa. The Fv/Fm ratio can give insight into the ability of plants to tolerate (indoor) air pollution by volatile organic chemicals (VOC). This index can be used for identification of suitable plants for treating/sequestering VOCs in contaminated air. PMID:24530730

  5. Nobel Method for Toluene Removal from Air Based on Ionic Liquid Modified Nano-Graphen

    Directory of Open Access Journals (Sweden)

    HAMID SHIRKHANLOO

    2015-10-01

    Full Text Available  The aim of this study was to investigate the removal of toluene from air through Nano-graphene modified by ionic liquid (NG-IL. The batch adsorption experiments in glass bottle of gas chromatography equipped with flame ionization detector (GC-FID were used. Graphene ultrahigh-quality synthesized by substrate-free gas-phase method in a single step and graphene sheets were deposited with ionic- liquid by thermal adsorption in acetone blank solution. Various conditions including contact time, amount of adsorbent, adsorbate concentration, humidity, and temperature were studied and optimized. NG-IL adsorbent was used for the adsorption of toluene vapor from gaseous media and the effect of different conditions such as; toluene concentration, humidity, and temperature on the adsorption were investigated. The Langmuir adsorption isotherms were employed for toluene by NG-IL adsorbent. The adsorption capacity was decreased by raising the sorbent humidity above 50 percent. The toluene capture capacity for NG-IL was 126 mg/g. The results of SEM, XRD, and TEM showed that, the NG-IL have beneficial surfaces for toluene removal. NG-IL as a novel adsorbent has not previously been used for the adsorption of pollutants.

  6. Induction of Micronuclei in Mice Lymphocytes Exposed to Microwave and Toluene

    Directory of Open Access Journals (Sweden)

    S. B. Mortazavi

    2005-01-01

    Full Text Available Increasing applications of microwave radiation are of great concern with regard to public health. Several studies have been conducted detect effects of microwave exposure genetic material leading to negative or questionable results. The Micronucleus (MN assay which is proved to be a useful method for detection of radiation exposure-induced cytogenetic damage was used in the present study to investigate the genotoxic effect of microwave and toluene alone and in combination in Balb/c lymphocytes. The electromagnetic field with two frequencies (980, 950 MHz, 200 KHz Mod, 5 w and 500 ppm Toluene applied for two weeks. Microwave irradiation had no significant effect on the frequency of micronucleus induced, but exposure of animals to toluene alone and in combination with microwave have significantly increased the induced micronucleus (p<0.05. Indeed combination exposure of microwave and toluene showed higher rates of micronucleus in comparison with toluene alone. This study indicated that microwave radiation cannot induce any significant cytogenetic effects but, in combination with toluene could show synergistic effect.

  7. Microbial Toluene Removal in Hypoxic Model Constructed Wetlands Occurs Predominantly via the Ring Monooxygenation Pathway.

    Science.gov (United States)

    Martínez-Lavanchy, P M; Chen, Z; Lünsmann, V; Marin-Cevada, V; Vilchez-Vargas, R; Pieper, D H; Reiche, N; Kappelmeyer, U; Imparato, V; Junca, H; Nijenhuis, I; Müller, J A; Kuschk, P; Heipieper, H J

    2015-09-15

    In the present study, microbial toluene degradation in controlled constructed wetland model systems, planted fixed-bed reactors (PFRs), was queried with DNA-based methods in combination with stable isotope fractionation analysis and characterization of toluene-degrading microbial isolates. Two PFR replicates were operated with toluene as the sole external carbon and electron source for 2 years. The bulk redox conditions in these systems were hypoxic to anoxic. The autochthonous bacterial communities, as analyzed by Illumina sequencing of 16S rRNA gene amplicons, were mainly comprised of the families Xanthomonadaceae, Comamonadaceae, and Burkholderiaceae, plus Rhodospirillaceae in one of the PFR replicates. DNA microarray analyses of the catabolic potentials for aromatic compound degradation suggested the presence of the ring monooxygenation pathway in both systems, as well as the anaerobic toluene pathway in the PFR replicate with a high abundance of Rhodospirillaceae. The presence of catabolic genes encoding the ring monooxygenation pathway was verified by quantitative PCR analysis, utilizing the obtained toluene-degrading isolates as references. Stable isotope fractionation analysis showed low-level of carbon fractionation and only minimal hydrogen fractionation in both PFRs, which matches the fractionation signatures of monooxygenation and dioxygenation. In combination with the results of the DNA-based analyses, this suggests that toluene degradation occurs predominantly via ring monooxygenation in the PFRs. PMID:26150458

  8. Ethyl ester production from (RBD palm oil

    Directory of Open Access Journals (Sweden)

    Oscar Mauricio Martínez Ávila

    2010-07-01

    Full Text Available This work develops a methodology for obtaining ethyl esters from RBD (refined, bleached and deodorised palm oil by evaluating the oil’s transesterification and separation. Two catalysts were first tested (KOH and NaOH by studying the effect of water presence on the reaction. The separation process was then evaluated by using water and water-salt and water-acid mixtures, establishing the agent offering the best results and carrying out the purification stage. Raw materials and products were characterised for comparing the latter with those obtained by traditional means and verifying the quality of the esters so produced; minimum differences were found bet-ween both. The proposed methodology thus allows esters to be used as raw material in petrochemical industry applications. A more profitable process can be obtained compared to those used today, given the amounts of separation agent so established (1% H3PO4 solution, in water. The overall process achieved 74.4% yield, based on the oil being used.

  9. Thermodynamic and chemical behavior of benzene under shock conditions

    Science.gov (United States)

    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.

  10. Radiolysis of isoctane in the presence of pyridine and benzene

    International Nuclear Information System (INIS)

    Gamma radiolysis of isoctane in the presence of benzene and pyridine at dose rate 4.50 Gy/s Was investigated. It was revealed that pyridine is a good acceptor of positive charge and excitement. Benzene is less effective acceptor of positive charge; it doesn't reduce the yield of excited isooctane molecules, formed according to non-ionic mechanism at room temperature, which equals 0.9+-0.1 for 100 eV absorbed energy for pyridine solutions and 0.85+-0.1 for 100 eV of absorbed energy for benzene solutions

  11. Neutron inelastic spectroscopy of benzene chemisorbed on raney platinum

    International Nuclear Information System (INIS)

    The neutron inelastic scattering spectrum of benzene adsorbed at 300 K on Raney platinum has been measured between 350 and 2250 cm-1. No deshydrogenation of the molecules is observed so that the benzene ring must be adsorbed parallel to the surface. Slight modifications of the force field of the model molecule (C6H6)Cr(CO)3 were introduced to account for the vibrational frequency shifts. The benzene molecule is found less perturbed on platinum than on nickel. The calculated frequencies of adsorbed C6H6 and C6D6 are used to reassign some modes previously observed by electron loss spectroscopy. (orig.)

  12. Ethyl coumarin-3-carboxylate: synthesis and chemical properties

    Directory of Open Access Journals (Sweden)

    Bakr F. Abdel-Wahab

    2014-03-01

    Full Text Available Ethyl coumarin-3-carboxylate occupies an important position in the organic synthesis and is used in production of biologically active compounds. Thus, the data published over the last few years on the methods of synthesis and chemical properties of ethyl coumarin-3-carboxylate are reviewed here for the first time. The reactions were classified as coumarin ring reactions and ester group reactions, and some of these reactions have been applied successfully to the synthesis of biologically and industrially important compounds.

  13. Parameters Affecting Ethyl Ester Production by Saccharomyces cerevisiae during Fermentation?

    OpenAIRE

    Saerens, S. M. G.; Delvaux, F.; Verstrepen, K. J.; van Dijck, P; Thevelein, J. M.; Delvaux, F. R.

    2007-01-01

    Volatile esters are responsible for the fruity character of fermented beverages and thus constitute a vital group of aromatic compounds in beer and wine. Many fermentation parameters are known to affect volatile ester production. In order to obtain insight into the production of ethyl esters during fermentation, we investigated the influence of several fermentation variables. A higher level of unsaturated fatty acids in the fermentation medium resulted in a general decrease in ethyl ester pro...

  14. Efficacy of Urinary Hippuric Acid as a Biomarker of Low Level Exposure to Toluene in Petroleum Depot Workers

    Directory of Open Access Journals (Sweden)

    ZAHRA NAGHAVI-KONJIN

    2015-10-01

    Full Text Available Exposure to toluene can be associate with genotoxicity, neurological dysfunction, reproductive toxicity, and etc. Biomonitoring of hippuric acid (HA is used for a long time as an occupational exposure index to toluene. The aim of this study was to explore efficiency of HA as a biomarker of exposure to low level of toluene for Iranian Petroleum Depot workers in 2011. Personal monitoring to toluene exposure for 45 workers (exposed group and 32 staff (control group were done according to the NIOSH Method No.1501, and simultaneous biological monitoring were conducted as urinary HA for all subjects. Pre and post shift urine samples were collected for analysis of HA by the NIOSH method No.8300 and urinary HA concentrations were corrected with creatinine content. Personal exposure of petroleum loading operators to toluene was 0.78±0.37ppm (Mean±SE. There was no statistical significant difference between urinary HA of exposed and control groups (staff. There was no statistical correlation between occupational exposure to toluene and internal exposure in term of HA. Occupational exposures to toluene were less than TLV in petroleum products loading operators. Due to exposure with low levels of toluene concentrations, however the content of urinary HA in gasoline operators were higher than BEI (Biological Exposure Index, but of no significant relationship between airborne concentrations of toluene and levels of HA in urine in all exposed groups. In conclusion, urinary HA is not appropriate biomarker of low level exposure to toluene.

  15. Peroxidase-dependent metabolism of benzene's phenolic metabolites and its potential role in benzene toxicity and carcinogenicity

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.T.; Yager, J.W.; Steinmetz, K.L. (Univ. of California, Berkeley (USA)); Eastmond, D.A. (Lawrence Livermore National Laboratory, CA (USA))

    1989-07-01

    The metabolism of two of benzene's phenolic metabolites, phenol and hydroquinone, by peroxidase enzymes has been studied in detail. Studies employing horseradish peroxidase and human myeloperoxidase have shown that in the presence of hydrogen peroxide phenol is converted to 4,4{prime}-diphenoquinone and other covalent binding metabolites, whereas hydroquinone is converted solely to 1,4-benzoquinone. Surprisingly, phenol stimulates the latter conversion rather than inhibiting it, an effect that may play a role in the in vivo myelotoxicity of benzene. Indeed, repeated coadministration of phenol and hydroquinone to B6C3F{sub 1} mice results in a dramatic and significant decrease in bone marrow cellularity similar to that observed following benzene exposure. A mechanism of benzene-induced myelotoxicity is therefore proposed in which the accumulation and interaction of phenol and hydroquinone in the bone marrow and the peroxidase-dependent formation of 1,4-benzoquinone are important components. This mechanism may also be responsible, at least in part, for benzene's genotxic effects as 1,4-benzoquinone has been shown to damage DNA and is shown here to induce multiple micronuclei in human lymphocytes. Secondary activation of benzene's phenol metabolites in the bone marrow may therefore play an important role in benzene's myelotoxic and carcinogenic effects.

  16. Isotope effect in diffusion of perdeuteriobenzene and 14C-substituted benzenes in unlabeled benzene at 250

    International Nuclear Information System (INIS)

    Mutual diffusion coefficients, obtained with a Gouy diffusiometer, are reported for the system perdeuteriobenzene--benzene (C6D6--C6H6) at 250. These results are consistent with tracer diffusion coefficients which have previously been obtained in this laboratory for 14C-substituted benzenes of varying molecular weight in benzene. Because of the small difference in refractive index between C6D6 and C6H6 only a limited range of concentrations was studied, and thus it was not meaningful to extrapolate the mutual data to give tracer diffusion coefficients. (U.S.)

  17. Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate using gas-liquid chromatography at T = (313.15, 323.15, and 333.15) K

    International Nuclear Information System (INIS)

    Activity coefficients at infinite dilution were determined for 24 solutes (n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, and alcohols) in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental results over the same temperature range. Selectivities and capacities at infinite dilution for the hexane/benzene and methanol/benzene separation problems were calculated from experimental infinite dilution activity coefficient values. The activity coefficients, enthalpies, selectivities, and capacities are discussed and compared to literature values for other ionic liquids, as well as industrial molecular solvents.

  18. Kinetics and Mechanism of Anilinolyses of Ethyl Methyl, Ethyl Propyl and Diisopropyl Chlorothiophosphates in Acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Barai, Hasi Rani; Lee, Hai Whang [Inha Univ., Incheon (Korea, Republic of); Ehtesham Ul Hoque, Md. [Govt. Brojomohun College, Barisal (Bangladesh)

    2013-12-15

    Nucleophilic substitution reactions of ethyl methyl (2), ethyl propyl (4) and diisopropyl (7) chlorothiopho-sphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at 55.0 .deg. C. A concerted mechanism is proposed based on the selectivity parameters. The deuterium kinetic isotope effects (DKIEs; k{sub H}/k{sub D}) are secondary inverse (k{sub H}/k{sub D} = 0.66-0.99) with 2, primary normal and secondary inverse (k{sub H}/k{sub D} = 0.78-1.19) with 4, and primary normal (k{sub H}/k{sub D} = 1.06-1.21) with 7. The primary normal and secondary inverse DKIEs are rationalized by frontside attack involving hydrogen bonded, four-center-type transition state, and backside attack involving in-line-type transition state, respectively. The anilinolyses of ten chloro-thiophosphates are examined based on the reactivity, steric effect of the two ligands, thio effect, reaction mechanism, DKIE and activation parameter.

  19. Ethyl glucuronide and ethyl sulfate in autopsy samples 27 years after death.

    Science.gov (United States)

    Politi, Lucia; Morini, Luca; Mari, Francesco; Groppi, Angelo; Bertol, Elisabetta

    2008-11-01

    The unique case of a 50-year-old known alcoholic whose corpse was exhumed 27 years after death is reported. The man apparently committed suicide by hanging, but many years later the case was questioned and homicide-linked to a long-lasting serial killer case-was suspected. Thus, the corpse was exhumed, and at the autopsy it was found to be naturally mummified. This fact permitted the analysis of body tissues with the aim to investigate the persistence of ethanol conjugates in the biological material 27 years after death. Fragments of liver and kidney, a blood clot, and a hair strand were collected and submitted to liquid chromatography tandem mass spectrometry analysis. Ethyl glucuronide (EtG) and ethyl sulfate (EtS) were identified and quantified in the liver, the kidney, and the blood clot. Hair analysis was found to be severely affected by ion suppression even after solid phase extraction. Consequently, EtG was identified in all hair segments (0-3 cm, 3-6 cm, and 6-10 cm), but no reliable quantification could be carried out. In summary, our findings demonstrate that, notwithstanding the expected conjugate degradation, EtG and EtS can be indicative of ante-mortem use of alcohol even many years after death. PMID:18661140

  20. Relationships between metabolic and non-metabolic susceptibility factors in benzene toxicity

    OpenAIRE

    Ross, David; Zhou, Hongfei

    2009-01-01

    Reactive metabolites formed from benzene include benzene oxide, trans, trans muconaldehyde, quinones, thiol adducts, phenolic metabolites and oxygen radicals. Susceptibility to the toxic effects of benzene has been suggested to occur partly because of polymorphisms in enzymes involved in benzene metabolism which include cytochrome P450 2E1, epoxide hydrolases, myeloperoxidase, glutathione-S-transferases and quinone reductases. However, susceptibility factors not directly linked to benzene met...

  1. Pervaporation Characteristics in Removal of Benzene from Water through Polystyrene-Poly (Dimethylsiloxane) IPN Membranes

    OpenAIRE

    Tatsuo Yajima; Hiroshi Tamura; Tadashi Shiraiwa; Takashi Miyata; Iusaku Sumida; Tadashi Uragami

    2011-01-01

    This paper focuses on the effects of the PSt content of polystyrene (PSt)-poly (dimethylsiloxane) (PDMS) interpenetrateing network (IPN) polymer membranes, on the pervaporation (PV) characteristics during the removal of benzene from an aqueous solution of dilute benzene. When an aqueous solution of 0.05wt% benzene was permeated through the PSt-PDMS IPN membranes, they showed high benzene/water selectivity. Both the permeability and the benzene/water selectivity of the membranes were enhanced ...

  2. Physiological and phylogenetic characterization of a stable chlorate-reducing benzene-degrading microbial community

    OpenAIRE

    Weelink, S.A.B.; Tan, N.C.G.; Broeke, H., ten; Doesburg, W.C.J., van; Langenhoff, A. A. M.; Gerritse, J.; Stams, A. J. M.

    2007-01-01

    stable anoxic enrichment culture was obtained that degraded benzene with chlorate as an electron acceptor. The benzene degradation rate was 1.65 mM benzene per day, which is similar to reported aerobic benzene degradation rates but 20¿1650 times higher than reported for anaerobic benzene degradation. Denaturing gradient gel electrophoresis of part of the 16S rRNA gene, cloning and sequencing showed that the culture had a stable composition after the seventh transfer. Five bacterial clones wer...

  3. H-D exchange between benzene and the OH groups of alumina

    International Nuclear Information System (INIS)

    H-D exchange of benzene with the OH groups of aluminas was investigated using FTIR spectroscopy. The reactions benzene-d6-alumina and benzene-alumina-d are of first order with respect to OH and benzene concentrations (E/sub A/ = 112 kJ/mol). They mainly take place on centers - probably Lewis acid-base pairs - which are poisoned by CO2 adsorbed as carbonate. 8 figures, 3 tables

  4. Biological monitoring of workers exposed to benzene in the coke oven industry.

    OpenAIRE

    Drummond, L; Luck, R; Afacan, A S; Wilson, H K

    1988-01-01

    Workers in the coke oven industry are potentially exposed to low concentrations of benzene. There is a need to establish a well validated biological monitoring procedure for low level benzene exposure. The use of breath and blood benzene and urinary phenol has been explored in conjunction with personal monitoring data. At exposures of about 1 ppm benzene, urinary phenol is of no value as an indicator of uptake/exposure. Benzene in blood was measured by head space gas chromatography but the co...

  5. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Reactions of energetic carbon-11 with benzene leading to acetylene

    International Nuclear Information System (INIS)

    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

  7. Positronium quenching in liquid and solid octanol and benzene

    DEFF Research Database (Denmark)

    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.

  8. Which ornamental plant species effectively remove benzene from indoor air?

    Science.gov (United States)

    Liu, Yan-Ju; Mu, Yu-Jing; Zhu, Yong-Guan; Ding, Hui; Crystal Arens, Nan

    Phytoremediation—using plants to remove toxins—is an attractive and cost effective way to improve indoor air quality. This study screened ornamental plants for their ability to remove volatile organic compounds from air by fumigating 73 plant species with 150 ppb benzene, an important indoor air pollutant that poses a risk to human health. The 10 species found to be most effective at removing benzene from air were fumigated for two more days (8 h per day) to quantify their benzene removal capacity. Crassula portulacea, Hydrangea macrophylla, Cymbidium Golden Elf., Ficus microcarpa var. fuyuensis, Dendranthema morifolium, Citrus medica var. sarcodactylis, Dieffenbachia amoena cv. Tropic Snow; Spathiphyllum Supreme; Nephrolepis exaltata cv. Bostoniensis; Dracaena deremensis cv. Variegata emerged as the species with the greatest capacity to remove benzene from indoor air.

  9. Variability of benzene exposure among filling station attendants

    International Nuclear Information System (INIS)

    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

  10. Benzene and diethyl sulphide in a gas jet transport system

    International Nuclear Information System (INIS)

    The effect of beam intensity and beam pulse repetition rate on the transport efficiency of 104Ag recoils [from the 103Rh(?,3n) reaction] in a He jet recoil transport system has been measured. Transport was effected by using the gas doped with benzene or diethyl sulphide. The effect of concentration for these two substances has been established and the maximum transport efficiencies were about 100% for benzene (22 ppm) and about 80% for diethyl sulphide (12 ppm). (Auth.)

  11. Exposure to benzene, occupational stress, and reduced birth weight

    OpenAIRE

    Chen, D.; Cho, S.; Chen, C; WANG X.; Damokosh, A.; Ryan, L.; SMITH, T.; Christiani, D.; X Xu

    2000-01-01

    OBJECTIVES—The association between birth weight and exposure to benzene, work stress, and other occupational and environmental hazards was investigated.?METHODS—In a large petrochemical industry, 792 pregnant workers were enrolled and followed up through delivery between May 1996 and December 1998. Exposure to benzene and other solvents was assessed by an industrial hygienist based on each woman's job title and workplace information. Other occupational and environmental exposures and personal...

  12. Co-metabolic conversion of toluene in anaerobic n-alkane-degrading bacteria.

    Science.gov (United States)

    Rabus, Ralf; Jarling, René; Lahme, Sven; Kühner, Simon; Heider, Johann; Widdel, Friedrich; Wilkes, Heinz

    2011-09-01

    Diverse microorganisms have been described to degrade petroleum hydrocarbons anaerobically. Strains able to utilize n-alkanes do not grow with aromatic hydrocarbons, whereas strains able to utilize aromatic hydrocarbons do not grow with n-alkanes. To investigate this specificity in more detail, three anaerobic n-alkane degraders (two denitrifying, one sulfate-reducing) and eight anaerobic alkylbenzene degraders (five denitrifying, three sulfate-reducing) were incubated with mixtures of n-alkanes and toluene. Whereas the toluene degradationers formed only the characteristic toluene-derived benzylsuccinate and benzoate, but no n-alkane-derived metabolites, the n-alkane degraders formed toluene-derived benzylsuccinate, 4-phenylbutanoate, phenylacetate and benzoate besides the regular n-alkane-derived (1-methylalkyl)succinates and methyl-branched alkanoates. The co-metabolic conversion of toluene by anaerobic n-alkane degraders to the level of benzoate obviously follows the anaerobic n-alkane degradation pathway with C-skeleton rearrangement and decarboxylation rather than the ?-oxidation pathway of anaerobic toluene metabolism. Hence, petroleum-derived aromatic metabolites detectable in anoxic environments may not be exclusively formed by genuine alkylbenzene degraders. In addition, the hitherto largely unexplored fate of fumarate hydrogen during the activation reactions was examined with (2,3-(2) H(2) )fumarate as co-substrate. Deuterium was completely exchanged with hydrogen at the substituted carbon atom (C-2) of the succinate adducts of n-alkanes, whereas it is retained in toluene-derived benzylsuccinate, regardless of the type of enzyme catalysing the fumarate addition reaction. PMID:21880102

  13. Shock-driven chemistry and reactive wave dynamics in benzene

    Science.gov (United States)

    Sheffield, Stephen; Dattelbaum, Dana; Coe, Joshua; Los Alamos National Laboratory Team

    2015-06-01

    Benzene is a stable organic chemistry molecule because of its electronic structure - aromatic stability is derived from its delocalized, ?-bonded, 6-membered planar ring structure. Benzene principal shock Hugoniot states have been reported previously by several groups, at both high and low pressures. Cusps (or discontinuities) in the shock Hugoniot provide evidence that chemical reactions take place under shockwave compression of benzene at input pressure conditions above 12 GPa. In other shock-driven experiments, spectral changes have been observed near this cusp condition, indicating that the cusp is associated with shock-driven chemical reaction(s). In this work, a series of gas-gun-driven plate impact experiments were performed to measure and quantify the details associated with shock-driven reactive flow in benzene. Using embedded electromagnetic gauges (with up to 10 Lagrangian gauge positions in-material in a single experiment) multiple, evolving wave structures have been measured in benzene when the inputs were above 12 GPa, with the details changing as the input pressure was increased. Detailed insights into the volume changes associated with the chemical reaction(s), reaction rates, and estimates of the bulk moduli of reaction intermediates and products were obtained. Using this new experimental data (along with the older experimental data from others), the benzene reactant and product Hugoniot loci have been modeled by thermodynamically complete equations of state.

  14. Occupational Risk Assessment of Benzene in Rubber Tire Manufacturing Workers

    Directory of Open Access Journals (Sweden)

    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.

  15. Analysis of the Novel Benzylsuccinate Synthase Reaction for Anaerobic Toluene Activation Based on Structural Studies of the Product

    OpenAIRE

    Beller, Harry R.; Spormann, Alfred M

    1998-01-01

    Recent studies of anaerobic toluene catabolism have demonstrated a novel reaction for anaerobic hydrocarbon activation: the addition of the methyl carbon of toluene to fumarate to form benzylsuccinate. In vitro studies of the anaerobic benzylsuccinate synthase reaction indicate that the H atom abstracted from the toluene methyl group during addition to fumarate is retained in the succinyl moiety of benzylsuccinate. Based on structural studies of benzylsuccinate formed during anaerobic, in vit...

  16. A Comparative Study on Removal of Toluene by Batch Reactor using Different Fungal Culture Isolated from Municipal Sewage Water

    OpenAIRE

    S.Bhuvaneswari

    2012-01-01

    The increasing rate of polluted gases in the atmosphere raises some of the major environmental and human health related problems that was recently suspected; hence the comparative study on removal of toluene by batch reactor using different fungal culture helps to minimize the toluene gas in the atmosphere. The comparative study on toluene removal was investigated by various parameters such as effect of different fungal culture with its characterization and effect of concentration. After star...

  17. (?6-Benzenedichlorido(dicyclohexylphenylphosphaneruthenium(II benzene sesquisolvate

    Directory of Open Access Journals (Sweden)

    Alfred Muller

    2012-12-01

    Full Text Available The asymmetric unit of the title compound, [RuCl2(C6H6(C18H27P]·1.5C6H6, contains one molecule of the RuII complex and one and a half solvent molecules as one of these is located about a centre of inversion. The RuII atom has a classical three-legged piano-stool environment being coordinated by an ?6-benzene ligand [Ru—centroid = 1.6964?(6?Å], two chloride ligands with an average Ru—Cl bond length of 2.4138?(3?Å and a dicyclohexylphenylphosphane ligand [Ru—P = 2.3786?(3?Å]. The effective cone angle for the phosphane was calculated to be 158°. In the crystal, weak C—H...Cl hydrogen bonds link the RuII complexes into centrosymmetric dimers. The crystal packing exhibits intra- and intermolecular C—H...? interactions resulting in a zigzag pattern in the [101] direction.

  18. Effect of Mixing on the Biological Degradation of Toluene under Aerobic Conditions

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2007-01-01

    Full Text Available The effectiveness of in-vessel bioremediation in reducing the concentration of toluene in contaminated soil under continuous and intermittent mixing conditions using invessel composting system. The results showed that there was a startup period (60 h during which the average temperature rose from 21 to 32 and 40°C (and then remained constant for the bioreactors with continuous and intermittent mixing, respectively. The increase in the temperature demonstrated the conversion of the complex organic carbon into H2O, CO2 and energy during mineralization (cell respiration process of carbon. The lower temperature of the bioreactor with continuous mixing (8-9°C mixing during the steady state period indicating that more heat was lost with exhaust gas from this bioreactor. Little changes were observed in the moisture contents of the mixture. Most of the moisture losses were through the exhaust gas. The analysis of the exhaust gas samples did not show identifiable toluene peaks but some unidentifiable peaks were present. By day 15, about 96.35 and 89.07 % of the initial toluene were removed by the bioreactors with intermittent and continuous mixing, respectively. These results indicate that in addition to reducing the energy requirement by 50 %, the bioreactor with intermittent mixing also reduces the time required for complete degradation. This method of bioremediation is very effective in removing toluene but the production of toluene derivatives during the biodegradation process should be investigated.

  19. High formation of secondary organic aerosol from the photo-oxidation of toluene

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt

    2009-01-01

    Full Text Available Toluene and other aromatics have long been viewed as the dominant anthropogenic secondary organic aerosol (SOA precursors, but the SOA mass yields from toluene reported in previous studies vary widely. Experiments conducted in the Carnegie Mellon University environmental chamber to study SOA formation from the photo-oxidation of toluene show significantly larger SOA production than parameterizations employed in current air-quality models. Aerosol mass yields depend on experimental conditions: yields are higher under higher UV intensity, under low-NOx conditions and at lower temperatures. The extent of oxidation of the aerosol also varies with experimental conditions, consistent with ongoing, progressive photochemical aging of the toluene SOA. Measurements using a thermodenuder system suggest that the aerosol formed under high- and low-NOx conditions is semi-volatile. These results suggest that SOA formation from toluene depends strongly on ambient conditions. An approximate parameterization is proposed for use in air-quality models until a more thorough treatment accounting for the dynamic nature of this system becomes available.

  20. Biological treatment of contaminated air with toluene in an airlift reactor

    Scientific Electronic Library Online (English)

    Alberto O, Vergara-Fernández; Erich F, Quiroz; Germán E, Aroca; Nelson A, Alarcón Pulido.

    2008-10-15

    Full Text Available In this work the variation in the toluene elimination capacity of an airlift bioreactor as a function of the toluene inlet load, using compost as the support material for the microorganisms was studied. In order to evaluate the flexibility of the reactor under changing toluene load, the toluene biod [...] egradation was measured for flows from 2.4 x 10-2 to 0.132 m³ h-1, and a concentration range from 1.4 to 0.8 g m-3. Results show a 100% removal efficiency (RE) for minor flows, however, for a flow increase of 450% the RE decreased 40%, reflecting the equipments weak flexibility in varying flows. Meanwhile the maximum elimination capacity obtained was 230 g m-3 h-1, for toluene loads of 550 g m-3 h-1, corresponding to a flow of 0.132 m³ h-1. It was found that a average biomass concentration in suspension of 3700 g m-3, reflected EC's of 203 g m-3 h-1.

  1. Psychological Autopsy and Necropsy of an Unusual Case of Suicide by Intravenous Toluene

    Science.gov (United States)

    Kulkarni, Ranganath R.; Hemanth Kumar, RG; Kulkarni, Pratibha R.; Kotabagi, Raghavendra B.

    2015-01-01

    Toluene (methylbenzene; volatile hydrocarbon) is an industrial solvent that causes major injury to the lungs; the organ being the first capillary bed encountered. We report an unusual case of suicide by a 24-year-old male, paramedical professional, with fatal outcome within 16 h of intentional, intravenous self-administration of toluene, with clinical presentation of acute respiratory distress syndrome. Psychological autopsy revealed severe depressive disorder and solvent (inhalant) abuse, with marital disharmony as the precipitating stressor for suicide. Necropsy revealed diffuse congestion of internal organs like lungs and liver, epicardial petechial hemorrhages, and gastric hemorrhages. Treatment of toluene poisoning includes supportive care as no specific antidote is available. Early and aggressive management may be conducive to a favorable outcome with minimal residual pulmonary sequelae. Relevant literature of toluene poisoning was identified via PubMed, PubChem, ToxNet, Hazardous Substances Data Bank (HSDB), Embase, and PsycINFO. To our knowledge, this is the first case of suicide by intravenous administration of toluene in the literature. PMID:25969615

  2. The effect of explicit solvent on photodegradation of decabromodiphenyl ether in toluene: insights from theoretical study.

    Science.gov (United States)

    Pan, Lu; Bian, Wensheng; Zhang, Jiaxu

    2013-06-27

    Polybrominated diphenyl ethers (PBDEs) have received special environmental concern because of their potential toxicity to humans and wildlife worldwide. However, their photochemical degradation mechanisms remain largely unknown. Herein, a PCM/TD-DFT scheme (time-dependent density functional theory combined with the polarizable continuum model) augmented with explicit solute-solvent interactions is used to explore the promotive effects of the toluene solvent on the photochemical degradation debromination of deca-BDE (BDE209). The face-to-face ?-? interactions between penta-bromine-substituted phenyl and toluene are investigated. The calculations indicate that the face-to-face ?-? interaction plays an important role in the low-lying ???* transitions of BDE209-toluene ?-stacking complex at around 300 nm in the sunlight region, which leads to notable changes for the ??* excited states and which promotes the breaking of the C-Br bonds. The photodegradation reaction via an intermolecular charge-transfer excited state formed by the electronic transition from a ? orbital of toluene to a ?* orbital of BDE209 is found to be a dominant mechanism. Our calculation results reveal the mechanism of how the participation of an explicit toluene solvent molecule catalyzes the photodegradation of BDE209 and explain the experimental results successfully. The present study may provide helpful information for the removal of PBDE contamination. PMID:23725399

  3. PANI and Graphene/PANI Nanocomposite Films — Comparative Toluene Gas Sensing Behavior

    Directory of Open Access Journals (Sweden)

    Mitesh Parmar

    2013-12-01

    Full Text Available The present work discusses and compares the toluene sensing behavior of polyaniline (PANI and graphene/polyaniline nanocomposite (C-PANI films. The graphene–PANI ratio in the nanocomposite polymer film is optimized at 1:2. For this, N-methyl-2-pyrrolidone (NMP solvent is used to prepare PANI-NMP solution as well as graphene-PANI-NMP solution. The films are later annealed at 230 °C, characterized using scanning electron microscopy (SEM as well Fourier transform infrared spectroscopy (FTIR and tested for their sensing behavior towards toluene. The sensing behaviors of the films are analyzed at different temperatures (30, 50 and 100 °C for 100 ppm toluene in air. The nanocomposite C-PANI films have exhibited better overall toluene sensing behavior in terms of sensor response, response and recovery time as well as repeatability. Although the sensor response of PANI (12.6 at 30 °C, 38.4 at 100 °C is comparatively higher than that of C-PANI (8.4 at 30 °C, 35.5 at 100 °C, response and recovery time of PANI and C-PANI varies with operating temperature. C-PANI at 50 °C seems to have better toluene sensing behavior in terms of response time and recovery time.

  4. Development of continuous deglycerolisation reactor for ethyl ester production

    Directory of Open Access Journals (Sweden)

    Ruamporn Nikhom

    2014-12-01

    Full Text Available In this work, the development of continuous deglycerolisation (CD reactor for ethyl ester production was investigated to improve the ethyl ester conversion. The device to assist separation of glycerol, in the CD unit, integrates transesterification (mixing zone and separation (settling zone into one unit. For reversible transesterification, removing glycerol during reaction can drive the equilibrium to the product side in order to achieve high conversion. Two models of device to assist separation of glycerol have been carried out to investigate the suitable conditions for ethyl ester production. Results showed that the fin-type model could separate higher amount of glycerol from the reaction system in order to achieve high transesterification conversion. The suitable conditions found in this study were: molar ratio of oil to ethanol of 1:5, KOCH3 concentration of 1.6 %wt. retention time of 15 min and reaction temperature of 70°C. At these conditions, ethyl ester’s purity and yield were 97.3%wt. and 92.0%wt., respectively. In addition, the fuel properties of the final ethyl ester product met the biodiesel standard for methyl ester which specified by Department of Energy Business.

  5. SENSITIVITY AND SPECIFICITY OF URINARY ETHYL GLUCURONIDE AND ETHYL SULFATE IN LIVER DISEASE PATIENTS

    Science.gov (United States)

    Stewart, Scott H.; Koch, David G.; Burgess, Douglas M.; Willner, Ira R.; Reuben, Adrian

    2012-01-01

    Background It is important to monitor alcohol use in the care of liver disease patients, but patient self-report can be unreliable. We therefore evaluated the performance of urine ethyl glucuronide (EtG) and ethyl sulfate (EtS) in detecting alcohol use in the days preceding a clinical encounter. Methods Subjects (n=120) were recruited at a university-based Hepatology clinic or during hospitalization. Alcohol consumption was ascertained by validated self-report measures. Urine EtG (cutoff 100 ng/mL) and EtS (cutoff 25 ng/mL) concentrations were assayed by a contracted laboratory using tandem mass spectrometry. The sensitivity and specificity of each biomarker in the detection of drinking during the 3 and 7 days preceding the clinic visit were determined, as well as the influence of liver disease severity on these results. Results Urine EtG (sensitivity 76%, specificity 93%) and urine EtS (sensitivity 82%, specificity 86%) performed well in identifying recent drinking, and liver disease severity does not affect biomarker performance. After elimination of one false negative self-report, urine EtG > 100 ng/mL was 100% specific for drinking within the past week, whereas 9% of the subjects without evidence of alcohol drinking for at least one week had EtS > 25 ng/mL. Conclusions Urine EtG and EtS can objectively supplement the detection of recent alcohol use in patients with liver disease. Additional research may determine optimal methods for integrating these tests into clinical care. PMID:22725265

  6. Ethyl glucuronide, ethyl sulfate, and ethanol in urine after intensive exposure to high ethanol content mouthwash.

    Science.gov (United States)

    Reisfield, Gary M; Goldberger, Bruce A; Pesce, Amadeo J; Crews, Bridgit O; Wilson, George R; Teitelbaum, Scott A; Bertholf, Roger L

    2011-06-01

    To determine the degree of ethanol absorption and the resultant formation and urinary excretion of its conjugated metabolites following intensive use of high ethanol content mouthwash, 10 subjects gargled with Listerine(®) antiseptic 4 times daily for 3¼ days. First morning void urine specimens were collected on each of the four study days and post-gargle specimens were collected at 2, 4, and 6 h after the final gargle of the study. Urine ethanol, ethyl glucuronide (EtG), ethyl sulfate (EtS), and creatinine were measured. Ethanol was below the positive threshold of 20 mg/dL in all of the urine specimens. EtG was undetectable in all pre-study urine specimens, but two pre-study specimens had detectable EtS (6 and 82 ng/mL; 16 and 83 ?g/g creatinine). Only one specimen contained detectable EtG (173 ng/mL; 117 ?g/g creatinine). EtS was detected in the urine of seven study subjects, but was not detected in the single specimen that had detectable EtG. The maximum EtS concentrations were 104 ng/mL and 112 ?g/g creatinine (in different subjects). Three subjects produced a total of eight (non-baseline) urinary EtS concentrations above 50 ng/mL or 50 ?g/g creatinine and three EtS concentrations exceeding 100 ng/mL or 100 ?g/g creatinine. In patients being monitored for ethanol use by urinary EtG and EtS concentrations, currently accepted EtG and EtS cutoffs of 500 ng/mL are adequate to distinguish between ethanol consumption and four times daily use of high ethanol content mouthwash. PMID:21619720

  7. Biosynthesis of ethyl (S)-4-chloro-3-hydroxybutanoate with an NADH-dependent reductase (ClCR) discovered by genome data mining using a modified colorimetric screening strategy.

    Science.gov (United States)

    He, Yu-Cai; Zhang, Dan-Ping; Lu, Yun; Tao, Zhi-Cheng; Ding, Yun; Wang, Li-Qun; Liu, Feng

    2015-01-01

    An NADH-dependent reductase (ClCR) was discovered by genome data mining. After ClCR was overexpressed in E. coli BL21, recombinant E. coli CCZU-T15 with high reductase activity and excellent stereoselectivity for the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (S)-4-chloro-3-hydroxybutanoate [(S)-CHBE] was screened using a modified high-throughput colorimetric screening strategy. After the reaction optimization, a highly stereoselective bioreduction of COBE into (S)-CHBE (>99% ee) with the resting cells of E. coli CCZU-T15 was successfully demonstrated in toluene-water (50:50, v/v) biphasic system. Biotransformation of 1000 mM COBE for 24 h in the biphasic system, (S)-CHBE (>99% ee) could be obtained in the high yield of 96.4%. Significantly, E. coli CCZU-T15 shows high potential in the industrial production of (S)-CHBE (>99% ee). PMID:25723767

  8. Transesterification catalyzed by polystyrene-supported chymotrypsin in toluene: the effect of neutralization of basic or acidic groups attaching to polystyrene resins.

    Science.gov (United States)

    Ohtani, N; Inoue, Y; Kobayashi, A; Sugawara, T

    1995-10-01

    Crosslinked polystyrene resins containing a low level of either basic or acidic groups were used for supports of alpha-chymotrypsin (CT), which catalyzed the transesterification of N-acetyl-L-phenylalanine ethyl ester (AcPheOEt) with propanol in toluene. With a minimal amount of water, CT was sorbed to the resins, basic or acidic groups of which were partly or fully neutralized by several soluble acids or bases. With an increasing degree of neutralization of basic resins by free acids, the rate of disappearance of AcPheOEt was decreased, whereas the by-product formation of AcPheOH, due to hydrolysis, was considerably suppressed, compared with the ester-exchange product, AcPheOPr. The pK(a) value of the neutralizing acid was also important for both CT activity and reaction selectivity. AcPheOPr was selectively produced at a certain range of pK(a) values. On the other hand, the neutralization of acidic resins with free amines enhanced the CT activity but a strong base promoted the formation of hydrolysis product. PMID:18623459

  9. Transformation of Chlorinated Benzenes and Toluenes by Ralstonia sp. Strain PS12 tecA (Tetrachlorobenzene Dioxygenase) and tecB (Chlorobenzene Dihydrodiol Dehydrogenase) Gene Products

    OpenAIRE

    Pollmann, Katrin; Beil, Stefan; Dietmar H. Pieper

    2001-01-01

    The tecB gene, located downstream of tecA and encoding tetrachlorobenzene dioxygenase, in Ralstonia sp. strain PS12 was cloned into Escherichia coli DH5? together with the tecA gene. The identity of the tecB gene product as a chlorobenzene dihydrodiol dehydrogenase was verified by transformation into the respective catechols of chlorobenzene, the three isomeric dichlorobenzenes, as well as 1,2,3- and 1,2,4-trichlorobenzenes, all of which are transformed by TecA into the respective dihydrodihy...

  10. An experimental study on regulated and unregulated pollutants from a spark ignition car fuelled on liquefied petroleum gas and Gasoline

    International Nuclear Information System (INIS)

    In the experimental study conducted on a spark ignition (SI) car running on a chassis dynamometer, fuelled on liquefied petroleum gas (LPG) and gasoline, carbon monoxide (CO) and total hydrocarbons (HC) decreased by 37.3% and 46.8%, respectively, while oxides of nitrogen (NOx) increased by 59.7% due to higher compression ratio with LPG, compared with gasoline. In case of LPG fuel, formaldehyde, acetaldehyde, propionaldehyde, 2-butanone, butyraldehyde, benzaldehyde and valeraldehyde decreased, leading to an over all decrease of about 35% and 26% in carbonyls and their ozone forming potential (OFP), respectively, compared with gasoline. Furthermore, benzene, toluene, ethyl benzene, xylene and styrene decreased, resulting in an overall decrease of 38.8% in volatile organic compounds (VOCs) and 39.2% in BTEX (benzene, toluene, ethyl benzene and xylene) species due to more complete combustion with LPG, compared with gasoline. Further, the OFP of VOCs with LPG was 6% lower than that with gasoline fuel. (author)

  11. Highly selective GaN-nanowire/TiO{sub 2}-nanocluster hybrid sensors for detection of benzene and related environment pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Aluri, Geetha S; Motayed, Abhishek; Davydov, Albert V; Oleshko, Vladimir P [Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Bertness, Kris A; Sanford, Norman A [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO 80305 (United States); Rao, Mulpuri V, E-mail: amotayed@nist.gov [Department of Electrical and Computer Engineering, George Mason University, Fairfax, VA 22030 (United States)

    2011-07-22

    Nanowire-nanocluster hybrid chemical sensors were realized by functionalizing gallium nitride (GaN) nanowires (NWs) with titanium dioxide (TiO{sub 2}) 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 TiO{sub 2} 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 TiO{sub 2} clusters after post-deposition anneal at 700 deg. 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 TiO{sub 2} 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.

  12. Chemical Dynamics Simulations of Benzene Dimer Dissociation.

    Science.gov (United States)

    Ma, Xinyou; Paul, Amit K; Hase, William L

    2015-06-25

    Classical chemical dynamics simulations were performed to study the intramolecular and unimolecular dissociation dynamics of the benzene dimer, Bz2 ? 2 Bz. The dissociation of microcanonical ensembles of Bz2 vibrational states, at energies E corresponding to temperatures T of 700-1500 K, were simulated. For the large Bz2 energies and large number of Bz2 vibrational degrees of freedom, s, the classical microcanonical (RRKM) and canonical (TST) rate constant expressions become identical. The dissociation rate constant for each T is determined from the initial rate dN(t)/dt of Bz2 dissociation, and the k(T) are well-represented by the Arrhenius eq k(T) = A exp(-E(a)/RT). The E(a) of 2.02 kcal/mol agrees well with the Bz2 dissociation energy of 2.32 kcal/mol, and the A-factor of 2.43 × 10(12) s(-1) is of the expected order-of-magnitude. The form of N(t) is nonexponential, resulting from weak coupling between the Bz2 intramolecular and intermolecular modes. With this weak coupling, large Bz2 vibrational excitation, and low Bz2 dissociation energy, most of the trajectories dissociate directly. Simulations, with only the Bz2 intramolecular modes excited at 1000 K, were also performed to study intramolecular vibrational energy redistribution (IVR) between the intramolecular and intermolecular modes. Because of restricted IVR, the initial dissociation is quite slow, but N(t) ultimately becomes exponential, suggesting an IVR time of 20.7 ps. PMID:26024045

  13. A novel toluene sensor based on ZnO-SnO2 nanofiber web

    International Nuclear Information System (INIS)

    We proposed in the present work that large-scale synthesis of sensitive ZnO-SnO2 nanofibres which can be obtained via a simple electrospinning method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction patterns (XRD) showed the average diameter of ZnO-SnO2 nanofibres ranging between 100 and 200 nm, the mixture of wurtzite (ZnO) and rutile (SnO2) structure in the composite fibers. The sensitivity of the obtained ZnO-SnO2 nanofibres to toluene was also investigated. The results showed that under optimal conditions, the calibration curve of response versus toluene concentration was linear in the range of 10-300 ppm, the response and recovery time were only several seconds, and sensitivity for toluene was desirable.

  14. Toluene Oxidation by Non-Thermal Plasma Combined with Palladium Catalysts

    Directory of Open Access Journals (Sweden)

    VasileIParvulescu

    2013-06-01

    Full Text Available The oxidation of toluene in air was investigated using a dielectric barrier discharge (DBD combined with a Pd/Al2O3 catalyst. When using only plasma, rather low selectivity towards CO2 was obtained: 32-35%. By filling the DBD reactor with Pd/Al2O3 catalyst the CO2 selectivity was significantly enhanced (80-90%, however, a large amount of toluene was desorbed from the catalyst when the discharge was operated. By filling a quarter of the discharge gap with catalyst and placing the rest of the catalyst downstream of the plasma reactor, an important increase of CO2 selectivity (~75% and a 15% increase in toluene conversion were achieved as compared to the results with plasma alone. The catalyst exhibited a very good stability in this reaction.

  15. Electrochemical Oxidation of Toluene on Glassy Carbon Electrodes in Organic Medium

    Scientific Electronic Library Online (English)

    Luis F., D´Elia; R., Ortíz.

    Full Text Available 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 involve adsorption processes, pure charge transfer reaction and couple chemical reactions. Additions of small quantities of water to the electrolyte cause a cathodic displacement of the oxidation peak potential; in other words, the electro-oxidation reaction is favoured.

  16. Molecular Modeling Studies on Aromatic Sulfonation. 1. Intermediates Formed in the Sulfonation of Toluene.

    Science.gov (United States)

    Morley, John O.; Roberts, D. W.

    1997-10-17

    Molecular modeling studies suggest that the mechanism of the sulfonation of toluene with sulfur trioxide proceeds via the formation of a pi-complex (4b) which rearranges to form a Wheland intermediate (5). This structure is unable to form toluenesulfonic acid (8) directly and prefers to react with a further molecule of sulfur trioxide to form a pyrosulfonate intermediate (6a) which undergoes a facile prototropic rearrangement involving the transfer of the ring hydrogen at the sp(3) carbon of 6a to the sulfonate oxygen atom to form the corresponding acid (7). The formation of toluenesulfonic acid (8) appears to arise from an exothermic reaction of between the pyrosulfonic acid (7) and toluene. The overall calculated thermodynamic change in moving from the reaction of one molecule of sulfur trioxide with toluene to the sulfonic acid (8b) is fully consistent with an estimated experimental value of -33.5 kcal mol(-1) for the same reaction using simple alkylbenzenes. PMID:11671852

  17. NMDA receptor binding is reduced within mesocorticolimbic regions following chronic inhalation of toluene in adolescent rats.

    Science.gov (United States)

    Dick, Alec Lindsay Ward; Pooters, Tine; Gibbs, Sarah; Giles, Emma; Qama, Ashleigh; Lawrence, Andrew John; Duncan, Jhodie Rubina

    2015-10-22

    The purposeful inhalation of volatile solvents, such as toluene, to induce self-intoxication is prevalent, particularly within adolescent populations. Chronic misuse results in cognitive and neurobiological impairments, as well as an increased risk for addictive behaviours in adulthood. Toluene-induced neuroadaptations within mesocorticolimbic circuitry are thought, in part, to mediate some of the adverse outcomes of toluene misuse, however our understanding of the neuroadaptive processes remains equivocal. An understanding of these processes is particularly important relative to exposure that occurs during adolescence and at concentrations that reflect various patterns of use. Therefore, we exposed male adolescent Wistar rats (postnatal day [PN] 27) to either air or low or high concentrations of inhaled toluene in a chronic and intermittent fashion (CIT, 3,000 or 10,000ppm) for 1 h/day, 3-5 times per week for 4 weeks to model different patterns of human inhalant abuse. Brains were subsequently analysed using autoradiography, qPCR and immunohistochemistry 3 days following the exposure period to investigate toluene-induced neuroadaptations within mesocorticolimbic circuitry. In CIT-exposed rats binding to N-methyl-D-aspartate (NMDA) receptors containing the GluN2B subunit, as determined using [(3)H]-ifenprodil, was decreased in a concentration-related manner in the caudal cingulate cortex, dorsal striatum and accumbens; however, this was not associated with changes in GluN2B protein expression. There were no differences in [(3)H]-epibatidine binding to heteromeric neuronal nicotinic acetylcholine (nACh) receptors. Relative expression of mRNA transcripts encoding NMDA, nACh, ?-aminobutyric acid type-A (GABAA) and dopamine receptor subunits was unchanged in all regions assessed following CIT. Our data suggest that adolescent CIT exposure impacts NMDA receptors within regions of corticostriatal circuitry, possibly via post-translational mechanisms. Dysfunctional glutamatergic signalling within corticostriatal regions may contribute to the adverse outcomes observed following adolescent toluene abuse. PMID:26236025

  18. High toluene exposure risk increases risk of olfactory dysfunction in furniture workers

    Directory of Open Access Journals (Sweden)

    Magdalena Wartono

    2015-04-01

    Full Text Available Background Few studies have investigated the impact on olfactory functioning of occupational exposure to toluene, an industrial solvent used in paints and cleaning fluids. The estimated olfactory dysfunction prevalence is 0.5–5%. Patients frequently do not complain about olfactory dysfunction. However, occupational exposure to chemicals may affect workers’ health and safety, because of their continuous inhalation. This study aimed to examine the relationship between toluene exposure and olfactory dysfunction in furniture workers. Methods This was a cross-sectional study involving 65 workers. Data collection was by observation and interview on demographic characteristics, history of habits, and symptoms of chronic rhinitis. Risk of exposure scores were evaluated from potential hazard, exposure level, duration of employment, type of work, use of masks, ventilation of work space, and education and training. Olfactory function was tested using Sniffin’ Sticks, and determination of environmental toluene level was by personal sampling. The odds ratio was used to test correlations between variables. Results Only 44 subjects could be analyzed, 37 (84.1% of whom had olfactory dysfunction. Workers with high toluene exposure had a significantly 12.5-fold risk of olfactory dysfunction in comparison with those with low exposure (OR=12.5; CI 95% 1.35 – 115.79. Conclusions Toluene exposure increases risk of olfactory dysfunction in furniture workers. Olfactory function testing should be considered for initial screening or periodic testing of furniture workers. Low toluene levels with a high proportion of olfactory dysfunction indicate that olfactory dysfunction is an early negative impact of chemical inhalation.

  19. Composition depth profiling of polystyrene/poly(vinyl ethyl ether) blend thin films by angle resolved XPS

    Energy Technology Data Exchange (ETDEWEB)

    Beamson, G. [National Centre for Electron Spectroscopy and Surface Analysis (NCESS), STFC Daresbury Laboratory, Warrington, Cheshire WA4 4AD (United Kingdom)], E-mail: graham.beamson@stfc.ac.uk; Mokarian-Tabari, P.; Geoghegan, M. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2009-04-15

    Angle resolved XPS (ARXPS) and scanning force microscopy (SFM) are used to study polystyrene/poly(vinyl ethyl ether) 50/50 wt% blend thin films spin cast from toluene solution, as a function of polystyrene molecular weight and film thickness. ARXPS is used to investigate the composition depth profile (CDP) of the blend thin films and SFM to study their surface morphology and miscibility. The CDPs are modelled by an empirical hyperbolic tangent function with three floating parameters. These are determined by non-linear least squares regression, their uncertainties estimated and the curve fit residuals analysed to demonstrate that the hyperbolic tangent CDP is a satisfactory fit to the ARXPS data. Conclusions are drawn regarding the behaviour of the blend thin films as the thickness and polystyrene molecular weight are varied. Flory-Huggins interaction parameters ({chi}) for the mixtures are calculated based upon the segregation data, and suggest a value of {chi} = 0.05 to be appropriate for this system.

  20. Canada-wide standard for benzene phase 2

    International Nuclear Information System (INIS)

    On the basis of available data, benzene is classified as carcinogenic to humans, and it led to the establishment, pursuant to the 1998 Canada-wide Accord on Environmental Harmonization of the Canadian Council of Ministers of the Environment (CCME) and its Canada-wide Environmental Standards Sub-Agreement, of the Canada-Wide Standard (CWS) for benzene. It is generally considered that any level of exposure carries some probability of harmful effects. A balancing act between achieving the best health and environmental protection possible and feasibility and costs associated with the reduction of emissions contributing to elevated levels of benzene in the air was performed for the development of this CWS. In June 2000, the Ministers of the Environment agreed to a phased approach to benzene reduction. To this effect, the Canada-Wide Standard for Benzene Phase 1 was ratified. By the end of 2000, a 30 per cent reduction in total benzene emissions form 1995 emission inventory levels was expected, according to Phase 1. The measures initiated during Phase 1 will continue beyond the time frame, and Phase 2 calls for a follow-through on those measures. Best management practices and jurisdictional regulations that will minimize emissions are recognized as part of Phase 2. Joint action in conjunction with other air issue programs should lead to additional reductions. Specifically, Phase 2 calls for an additional reduction of 6 kilotonnes in benzene emissions for existing facilities by the end of 2010. The minimization of benzene emissions through the application of best available pollution prevention and control techniques is contained for new and expanding facilities. The implementation of the CWS comprises the follow-up of existing initiatives resulting from the application of Phase 1 and the promotion and application of best management practices for new and expanding facilities, the determination and tracking of ancillary emission reductions of benzene realized as a result of other CWS initiatives, and the monitoring and reporting of progress. A comprehensive report, due in 2011, will be followed by a review of the CWS

  1. Lymphocyte chromosome breakage in low benzene exposure among Indonesian workers

    Directory of Open Access Journals (Sweden)

    Dewi S. Soemarko

    2015-01-01

    Full Text Available Background: Benzene has been used in industry since long time and its level in environment should be controled. Although environmental benzene level has been controlled to less than 1 ppm, negative effect of benzene exposure is still observed, such as chromosome breakage. This study aimed to know the prevalence of lymphocyte chromosome breakage and the influencing factors among workers in low level benzene exposure.Methods: This was a cross sectional study in oil & gas industry T, conducted between September 2007 and April 2010. The study subjects consisted of 115 workers from production section and head office. Data on type of work, duration of benzene exposure, and antioxidant consumption were collected by interview as well as observation of working process. Lymphocyte chromosome breakage was examined by banding method. Analysis of relationship between chromosome breakage and risk factors was performed by chi-square and odd ratio, whereas the role of determinant risk factors was analyzed by multivariate forward stepwise.Results: Overall lymphocyte chromosome breakage was experieced by 72 out of 115 subjects (62.61%. The prevalence among workers at production section was 68.9%, while among administration workers was 40% (p > 0.05. Low antioxidant intake increases the risk of chromosome breakage (p = 0.035; ORadjusted = 2.90; 95%CI 1.08-7.78. Other influencing factors are: type of work (p = 0,10; ORcrude = 3.32; 95% CI 1.33-8.3 and chronic benzene exposure at workplace (p = 0.014; ORcrude = 2.61; 95% CI 1.2-5.67, while the work practice-behavior decreases the lymphocyte chromosome breakage (p = 0.007; ORadjusted = 0.30; 95% CI 0.15-0.76.Conclusion: The prevalence of lymphocyte chromosome breakage in the environment with low benzene exposure is quite high especially in production workers. Chronic benzene exposure in the workplace, type of work, and low antioxidant consumption is related to lymphocyte chromosome breakage. Thus, benzene in the workplace should be controlled to less than 1 ppm, and the habit of high antioxidant consumption is recommended.

  2. Absorption of CO, H sub 2 and CH sub 4 in toluene and copper(I) tetrachloroaluminate-toluene solutions at elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Koschel, J.; Pfennig, A.; Henschke, M.; Hartmann, H. (RWTH Aachen, Aachen (Germany). Lehrstuhl II fuer Verfahrenstechnik)

    Solubilities of the coal-gasification products CO, H{sub 2}, and CH{sub 4} in pure toluene have been measured at temperatures between 249 and 343 K and pressures up to 7 MPa. Phase equilibria of CO and copper(I) tetrachloroaluminate-toluene solutions are presented between 254 and 333 K and pressures up to 9.5 MPa. In this absorbent, reversible chemical reactions occur resulting in a formation of several bimetallic salt complexes having a high bonding capacity for CO. Solubility measurements with H{sub 2} and CH{sub 4} in this agent show that these gases do not undergo any chemical reaction. 11 refs., 7 figs., 3 tabs.

  3. Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

    CERN Document Server

    Kolesniková, L; Cernicharo, J; Alonso, J L; Daly, A M; Gordon, B P; Shipman, S T

    2014-01-01

    New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH$_{3}$SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is $\\simeq$ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.

  4. Toluene oxidation by non-thermal plasma combined with palladium catalysts

    OpenAIRE

    VasileIParvulescu; MonicaMagureanu

    2013-01-01

    The oxidation of toluene in air was investigated using a dielectric barrier discharge (DBD) combined with a Pd/Al2O3 catalyst. When using only plasma, rather low selectivity towards CO2 was obtained: 32-35%. By filling the DBD reactor with Pd/Al2O3 catalyst the CO2 selectivity was significantly enhanced (80-90%), however, a large amount of toluene was desorbed from the catalyst when the discharge was operated. By filling a quarter of the discharge gap with catalyst and placing the rest of the...

  5. Surface microfabrication of silica glass by excimer laser irradiation of toluene solution

    Science.gov (United States)

    Niino, Hiroyuki; Yasui, Yoshimi; Ding, Ximing; Narazaki, Aiko; Sato, Tadatake; Kawaguchi, Yoshizo; Yabe, Akira

    2003-07-01

    Laser-induced backside wet etching of silica glass plates was performed by the excitation of a pure toluene solution with a ns-pulsed KrF excimer laser at 248 nm. Well-defined grid micropattern was fabricated without debris and microcrack around the etched area. To understand the etching mechanism, the formation and propagation of shockwave and bubble were monitored by time-resolved optical microscopy at the interface between the silica glass and the toluene solution after laser irradiation. Transient high-pressure as well as high-temperature generated by UV laser irradiation plays a key role in the etching process.

  6. Part 1: Vadose-zone column studies of toluene (enhanced bioremediation) in a shallow unconfined aquifer

    Science.gov (United States)

    Tindall, J.A.; Friedel, M.J.; Szmajter, R.J.; Cuffin, S.M.

    2005-01-01

    The objectives of the laboratory study described in this paper were (1) to determine the effectiveness of four nutrient solutions and a control in stimulating the microbial degradation of toluene in the unsaturated zone as an alternative to bioremediation methodologies such as air sparging, in situ vitrification, or others (Part I), and (2) to compare the effectiveness of the addition of the most effective nutrient solution from Part I (modified Hoagland type, nitrate-rich) and hydrogen peroxide (H2O2) on microbial degradation of toluene for repeated, simulated spills in the unsaturated zone (Part II). For Part 1, fifteen columns (30-cm diameter by 150-cm height), packed with air-dried, 0.25-mm, medium-fine sand, were prepared to simulate shallow unconfined aquifer conditions. Toluene (10 mL) was added to the surface of each column, and soil solution and soil gas samples were collected from the columns every third day for 21 days. On day 21, a second application of toluene (10 mL) was made, and the experiment was run for another 21 days. Solution 4 was the most effective for microbial degradation in Part I. For Part II, three columns were designated nutrient-rich 3-day toluene columns and received toluene injections every 3 days; three columns were designated as nutrient-rich 7-day columns and received toluene injections every 7 days; and two columns were used as controls to which no nutrient was added. As measured by CO2 respiration, the initial benefits for aerobic organisms from the O2 enhancement were sustained by the bacteria for only a short period of time (about 8 days). Degradation benefits from the nutrient solution were sustained throughout the experiment. The O2 and nutrient-enhanced columns degraded significantly more toluene than the control columns when simulating repeated spills onto the unsaturated zone, and demonstrated a potentially effective in situ bioremediation technology when used immediately or within days after a spill. The combined usage of H 2O2 and nitrate-rich nutrients served to effectively maximize natural aerobic and anaerobic metabolic processes that biodegrade hydrocarbons in petroleum-contaminated media. Applications of this technology in the field may offer economical advantages to other, more intrusive abatement technologies. ?? Springer 2005.

  7. The N4-hydroxycytidine reduction system in toluenized cells of Salmonella typhimurium

    International Nuclear Information System (INIS)

    Enzymatic reduction of N4-hydroxycytidine to cytidine in Salmonella typhimurium is highly specific. The reaction occurs only at the nucleoside level. Free base or its 1-methyl analogue is not reduced. The pH optimum shows a broad plateau with a maximum at pH 7.0. The apparent Ksub(m) value, estimated in the toluene-treated cells, is 4.8mM and Vsub(max) 1.4nmoles/min/mg of wet bacterial weight. The reaction is NADH-dependent, although in toluenized bacterial cells it can occur without addition of any exogenous factor. (author)

  8. Response of solvent-exposed printers and unexposed controls to six-hour toluene exposure

    DEFF Research Database (Denmark)

    Bælum, Jesper; Andersen, I B; Lundqvist, G R; Mølhave, Lars; Pedersen, O F; Vaeth, M; Wyon, David

    1985-01-01

    The acute effects of toluene were studied in 43 male printers and 43 control subjects matched according to sex, age, educational level, and smoking habits. The mean age of the subjects was 36 (range 29-50) years. The printers had been exposed to solvents for 9 to 25 years during employment at flexo and rotogravure printing plants, while the controls had no history of solvent exposure. Each subject was exposed once in a climate chamber to either 100 ppm of toluene or clean air for 6.5 h preceded ...

  9. Characterization of activated sludge bacteria capable of growth on toluene and other aromatic compounds

    OpenAIRE

    Nahar, Nazmun

    1994-01-01

    A total of fifteen bacteria from activated sludge were isolated for th eir ability to grow on aromatic substrates as the sole source of carbon and energy. They were identified as members of the genera Pseudomonas and Aeromonas. Four P . putida spp. To-1, To-3, To-5, Na-13 and one A. caviae sp.To-4 capable of good growth on toluene were selected for fu rther study. All five bacteria were capable of growth on toluene, benzoic acid, m-toluic acid, ethylbenzene, pseudocumene, m - and p-xylene...

  10. Influence of Gold on Hydrotalcite-like Compound Catalysts for Toluene and CO Total Oxidation

    Directory of Open Access Journals (Sweden)

    Eric Genty

    2013-12-01

    Full Text Available X6Al2HT500 hydrotalcites, where X represents Mg, Fe, Cu or Zn were synthetized and investigated before and after gold deposition for toluene and CO total oxidation reactions. The samples have been characterized by specific areas, XRD measurements and Temperature Programmed Reduction. Concerning the toluene total oxidation, the best activity was obtained with Au/Cu6Al2HT500 catalyst with T50 at 260 °C. However, catalytic behavior of Au/X6Al2HT500 sample in both reactions depends mainly on the nature of the support.

  11. Binge Toluene Exposure in Pregnancy and Pre-weaning Developmental Consequences in Rats

    OpenAIRE

    Bowen, Scott E; Hannigan, John H.

    2013-01-01

    The persistent rate of abuse of inhaled organic solvents, especially among women of child-bearing age, raises the risk for teratogenic effects of maternal toluene abuse. In this study, timed-pregnant Sprague Dawley rats were exposed from Gestation Day (GD) 8 to GD20 to 12,000 or 8,000 parts per million (ppm) toluene, or 0 ppm (controls) for 30 min twice daily, 60 min total daily exposure. Pups were assessed from postnatal day (PN) 4 to PN21 using a developmental battery measuri...

  12. Products of the Benzene + O(3P) Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Meloni, Giovanni; Trevitt, Adam J.; Epifanovsky, Evgeny; Krylov, Anna I.; Sirjean, Baptiste; Dames, Enoch; Wang, Hai

    2009-12-21

    The gas-phase reaction of benzene with O(3P) is of considerable interest for modeling of aromatic oxidation, and also because there exist fundamental questions concerning the prominence of intersystem crossing in the reaction. While its overall rate constant has been studied extensively, there are still significant uncertainties in the product distribution. The reaction proceeds mainly through the addition of the O atom to benzene, forming an initial triplet diradical adduct, which can either dissociate to form the phenoxy radical and H atom, or undergo intersystem crossing onto a singlet surface, followed by a multiplicity of internal isomerizations, leading to several possible reaction products. In this work, we examined the product branching ratios of the reaction between benzene and O(3P) over the temperature range of 300 to 1000 K and pressure range of 1 to 10 Torr. The reactions were initiated by pulsed-laser photolysis of NO2 in the presence of benzene and helium buffer in a slow-flow reactor, and reaction products were identified by using the multiplexed chemical kinetics photoionization mass spectrometer operating at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory. Phenol and phenoxy radical were detected and quantified. Cyclopentadiene and cyclopentadienyl radical were directly identified for the first time. Finally, ab initio calculations and master equation/RRKM modeling were used to reproduce the experimental branching ratios, yielding pressure-dependent rate expressions for the reaction channels, including phenoxy + H, phenol, cyclopentadiene + CO, which are proposed for kinetic modeling of benzene oxidation.

  13. Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2003-01-01

    Full Text Available Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene with hydroxyl radicals in the presence of NOx have been investigated using comprehensive gas chromatography (GCxGC. A GCxGC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE, a large volume outdoor reaction chamber in Valencia, Spain. Experiments were carried as part of the EXACT project (Effects of the oXidation of Aromatic Compounds in the Troposphere. Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 minutes, allowing the evolution of species to be followed over oxidation periods of 3-6 hours. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards. For toluene reactions, observed oxygenated intermediates found included the co-eluting pair a-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GCxGC for the measurement of the parent aromatics generally showed good agreement. Comparison of the concentrations observed by GCxGC to concentration-time profiles simulated using the Master Chemical Mechanism, MCMv3, demonstrates that this mechanism significantly over-predicts the concentrations of many product compounds and highlights the uncertainties which exist in our understanding of the atmospheric oxidation of aromatics.

  14. Wet deposition of hydrocarbons in the city of Tehran-Iran

    OpenAIRE

    Zahed, Mohammad Ali; Pardakhti, Alireza; Mohajeri, Leila; Bateni, Farshid

    2009-01-01

    Air pollution in the city of Tehran has been a major problem for the past three decades. The direct effects of hydrocarbon contaminants in the air are particularly important such as their carcinogenic, mutagenic, and teratogenic effects which can be transported to other environments via dry and wet deposition. In the present study, rainwater samples were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethyl benzene, and xylene (BTEX) as well as fuel fi...

  15. The impact of hydrocarbon emissions on regional air quality in a South African metropolitan area / Hermanus Johannes van der Walt.

    OpenAIRE

    Van der Walt, Hermanus Johannes

    2008-01-01

    The understanding of the source, transport, fate and impact of anthropogenic emissions is critical if the management of air pollution is to be effective in improving and sustaining acceptable air quality in a given area. In an attempt to improve the current lack of information pertaining to volatile organic compounds (VOC) and specifically benzene, toluene, xylene and ethyl benzene (BTEX), a study was conducted in the metropolitan area of Sasolburg, an industrial town approximately 70 kilomet...

  16. Health assessment for Nutmeg Valley, Wolcott, Connecticut, Region 1. CERCLIS No. CTSI88045. Preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    1988-05-02

    The Nutmeg Valley Industrial Park is listed on the National Priorities List. The site is an industrial park containing 40 companies (light industry metal working and finishing) and 20 private residences. The contaminants present in groundwater at the site are trichloroethylene, benzene, ethyl benzene, toluene, xylene, methylene chloride, trans 1,2-dichloroethane, 1,1,1-trichloroethane, tetrachloroethylene, pentane, carbon tetrachloride, and chloroform. Investigation into the extent of contamination in other pathways is ongoing.

  17. Extraction equilibrium of organic acids by toluene solution of tri-n-octylamine; Tri-n-octylamine no toluene yoeki ni yoru yukisan no chushutsu heiko

    Energy Technology Data Exchange (ETDEWEB)

    Sana, T.; Nagayoshi, K. [Yoshitama Surface Finishing Co. Ltd., Miyazaki (Japan); Shiomori, K.; Baba, Y.; Kawano, Y. [Miyazaki University, Miyazaki (Japan). Faculty of Engineering

    1997-03-10

    To separate fatty acids from fermentation liquid and organic acid waste liquid, the extraction equilibria of various organic acids, such as acetic acid, malic acid, citric acid and lactic acid, with tri-n-octylamine (TOA) as extractant in toluene were measured. Under this experimental condition, all fatty acids were not distributed in toluene. Organic acid [A], reacted with TOA [B], to form ion complexes in toluene. The formed complex species and equilibrium constants were estimated by graphical analysis. The complexes were AnB (n=1,2,3,4,5,6) for acetic acid, (AB)n (n=1,5) for malic acid, (AB)n (n=1,6) for citric acid, and AnBm ((n{ge}m) n=1,2,3,4,5/ m=1,2) for lactic acid, respectively. The experimental results could be explained by the proposed reaction models. Using individual equilibrium constants determined, separation process of organic acids by TOA can be designed. 16 refs., 14 figs., 2 tabs.

  18. The interaction of benzene and ethylene under Titan surface conditions

    Science.gov (United States)

    Beauchamp, Patricia; Vu, Tuan H.; Cable, Morgan L.; Hodyss, Robert P.; Choukroun, Mathieu

    2014-11-01

    Previously, we have reported the discovery and characterization of a new co-crystal formed from benzene and ethane (Vu et al. 2014 J. Phys Chem. A 118, 4087; Cable et al. 2014 GRL 41, doi:10.1002/2014GL060531). This co-crystal would be thermodynamically stable on Titan’s surface, and forms easily from the interaction of liquid ethane and solid benzene, as well as from the evaporation of benzene saturated solutions of ethane. These results imply that the benzene-ethane co-crystal may be an important component of Titan’s evaporate deposits. The formation of these kinds of organic co-crystals may influence evaporite characteristics, such as particle size and infrared spectral properties.Here, we report our most recent experiments exploring the interaction between benzene and ethylene. Ethylene has been detected in Titan’s atmosphere, and some photochemical models predict a significant flux to the surface. We performed experiments examining the interaction of liquid ethylene with solid benzene under Titan-like conditions (90-150 K and 1 bar N2), using micro-Raman spectroscopy and optical microscopy. We will present Raman spectra and vibrational analyses of the interaction, and implications for Titan’s surface chemistry and evolution.This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Copyright 2014, California Institute of Technology. Support by the NASA Astrobiology Institute (Titan as a Prebiotic Chemical System), the NASA Outer Planets Research Program and government sponsorship are gratefully acknowledged.

  19. Assessment of occupational exposure to BTEX compounds at a bus diesel-refueling bay: A case study in Johannesburg, South Africa.

    Science.gov (United States)

    Moolla, Raeesa; Curtis, Christopher J; Knight, Jasper

    2015-12-15

    Of increasing concern is pollution by volatile organic compounds, with particular reference to five aromatic hydrocarbons (benzene, toluene, ethyl benzene and two isomeric xylenes; BTEX). These pollutants are classified as hazardous air pollutants. Due to the potential health risks associated with these pollutants, BTEX concentrations were monitored at a bus diesel-refueling bay, in Johannesburg, South Africa, using gas chromatography, coupled with a photo-ionization detector. Results indicate that o-xylene (29-50%) and benzene (13-33%) were found to be the most abundant species of total BTEX at the site. Benzene was within South African occupational limits, but above international occupational exposure limits. On the other hand, occupational concentrations of toluene, ethyl-benzene and xylenes were within national and international occupational limits throughout the monitoring period, based on 8-hour workday weighted averages. Ethyl-benzene and p-xylene concentrations, during winter, correspond to activity at the site, and thus idling of buses during refueling may elevate results. Overall, occupational air quality at the refueling bay is a matter of health concern, especially with regards to benzene exposure, and future reduction strategies are crucial. Discrepancies between national and international limit values merit further investigation to determine whether South African guidelines for benzene are sufficiently precautionary. PMID:26282739

  20. In vitro metabolism of [14C]-toluene by human and rat liver microsomes and liver slices

    International Nuclear Information System (INIS)

    Toluene metabolites produced by liver microsomes from six human donors included benzylalcohol (Balc), benzaldehyde (Bald) and benzoic acid (Bacid). Microsomes from only one human donor metabolized toluene to p-cresol and o-cresol. Human liver microsomes also metabolized Balc to Bald. Balc metabolism required NADPH, was inhibited by carbon monoxide, and was decreased at a buffer pH of 10. Balc metabolism was not inhibited by ADP-ribose or sodium azide. These results suggest that cytochrome P450 is responsible for the in vitro metabolism of Balc by human liver microsomes. Toluene metabolites formed by human liver slices and released into the incubation media included hippuric acid, and Bacid. Cresols or cresol-conjugates were not detected in liver slice incubation media from any human donor. Toluene metabolism by human liver was compared to metabolism by comparable liver preparations from male Fischer F344 rats. Rates of toluene metabolism by human liver microsomes and liver slices were 9-fold and 1.3-fold greater than for rat liver, respectively. Covalent binding of toluene to human liver microsomes and liver slices was 21-fold and 4-fold greater than for comparable rat liver preparations. Covalent binding of toluene to human microsomes required NADPH, was significantly decreased by coincubation with 4 mM cysteine or 4 mM glutathione, and radioactivity associated with microsomes was decreased by subsequent digestion of microsomes with protease. These results suggest that toluene metabolism and covalent binding of toluene are underestimated if the male Fischer 344 rat is used as a model for human toluene metabolism

  1. Reactions of osmabenzene with silver/copper acetylides: from metallabenzene to benzene.

    Science.gov (United States)

    Han, Feifei; Li, Jinhua; Zhang, Hong; Wang, Tongdao; Lin, Zhenyang; Xia, Haiping

    2015-01-01

    The transformations of metallabenzene to substituted benzenes have been achieved by reactions of osmabenzenes with silver/copper acetylides. In this investigation, novel tetraphenylphosphonium salts containing two phosphonium substituents on the same benzene ring are generated. PMID:25412982

  2. Benzene solubility in ionic liquids: working toward an understanding of liquid clathrate formation.

    Science.gov (United States)

    Pereira, Jorge F B; Flores, Luis A; Wang, Hui; Rogers, Robin D

    2014-11-17

    The solubility of benzene in 15 imidazolium, pyrrolidinium, pyridinium, and piperidinium ionic liquids has been determined; the resulting, benzene-saturated ionic liquid solutions, also known as liquid clathrates, were examined with (1) H and (19) F nuclear magnetic resonance spectroscopy to try and understand the molecular interactions that control liquid clathrate formation. The results suggest that benzene interacts primarily with the cation of the ionic liquid, and that liquid clathrate formation (and benzene solubility) is controlled by the strength of the cation-anion interactions, that is, the stronger the cation-anion interaction, the lower the benzene solubility. Other factors that were determined to be important in the final amount of benzene in any given liquid clathrate phase included attractive interactions between the anion and benzene (when significant), and larger steric or free volume demands of the ions, both of which lead to greater benzene solubility. PMID:25297708

  3. 46 CFR Appendix A to Subpart C to... - Sample Substance Safety Data Sheet, Benzene

    Science.gov (United States)

    2010-10-01

    ...Sample Substance Safety Data Sheet, Benzene A Appendix...Sample Substance Safety Data Sheet, Benzene I. Substance... II. Health Hazard Data (a) Ways in which...those operations in which engineering controls or...

  4. Ethyl­enedi­ammonium chloride thio­cyanate

    OpenAIRE

    Karoui, Sahel; Kamoun, Slaheddine; Michaud, François

    2013-01-01

    In the ethyl­enedi­ammonium dication of the title salt, C2H10N2 2+·Cl?·SCN?, the N—C—C—N torsion angle is 72.09?(12)°. In the crystal, an extensive three-dimensional hydrogen-bonding network, formed by N—H?Cl and N—H?N hydrogen bonds, holds all the ions together.

  5. Asymmetric hydrogenation of ethyl pyruvate: Diffusion effects on enantioselectivity

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yongkui; Wang, Jian; LeBlond, C. [Merck & Co., Inc., Rahway, NJ (United States)] [and others

    1996-07-01

    Enantioselectivity in the hydrogenation of ethyl pyruvate over cinchona-alkaloid-modified Pt has been studied. Kinetic studies indicated different mechanisms in different reaction regimes. Solution hydrogen concentration strongly corrrelated with reaction rates and enantioselectivity. 28 refs., 5 figs., 2 tabs.

  6. Health-based recommended occupational exposure limits for ethyl acrylate.

    OpenAIRE

    Maclaine Pont, M.A.

    1990-01-01

    The experimental no effect level was 20 mg ethyl acrylate/m3. The exposure with slight effects was at 100 mg/m3. The real no effect level is between 20 and 100 mg/m3. Therefore an occupational exposure limit of 20 mg eth-acr/m3 TWA 8 hr is advised with "H" (skin absorption possible).

  7. Ethyl 2-hydroxy-2-phenyl-2-(thiazol-2-ylacetate

    Directory of Open Access Journals (Sweden)

    Carl J. Mallia

    2015-05-01

    Full Text Available This short note describes the synthesis of the title compound through spontaneous aerobic oxidation of ethyl 2-phenyl-2-(thiazol-2-ylacetate. Due to the prevalence of such functional motifs in biologically active substances, we believe the oxidation encountered highlights an important degradation pathway worthy of note.

  8. Synthesis of Ethyl Nalidixate: A Medicinal Chemistry Experiment

    Science.gov (United States)

    Leslie, Ray; Leeb, Elaine; Smith, Robert B.

    2012-01-01

    A series of laboratory experiments that complement a medicinal chemistry lecture course in drug design and development have been developed. The synthesis of ethyl nalidixate covers three separate experimental procedures, all of which can be completed in three, standard three-hour lab classes and incorporate aspects of green chemistry such as…

  9. Adsorption of benzene, phenol and naphthalene on platinum

    International Nuclear Information System (INIS)

    A combination of radiotracer and electrochemical methods was used to study the adsorption of benzene, phenol and naphthalene on smooth and platinized platinum. The adsorption kinetics of these substances was measured at different pH values of the solution, and the dependence of adsorption on electrode potential and concentration of adsorbate in the solution was determined. The irreversible nature of the adsorption of benzene, phenol and naphthalene on platinum was established. In the case of phenol and naphthalene, it was shown that at phi?=0.05V, hydrogenation products of these substances accumulate at the electrode. (author)

  10. Unleaded gasoline with reduction in benzene and aromatics

    International Nuclear Information System (INIS)

    The trend today is towards making gasoline more environment and human friendly or in other words making gasoline a really clean fuel. This paper covers the ill effects of benzene and aromatics and the driving force behind their reduction in gasoline worldwide. It addresses health concerns specifically, and the theme is unleaded gasoline without simultaneously addressing reduction in benzene and aromatics is more harmful. The paper cites worldwide case studies, and also the World Bank (WB), Government of Pakistan (GoP), and United Nations (UN) efforts in this area in Pakistan. (author)

  11. Degree of branching in hyperbranched poly(glycerol-co-diacid)s synthesized in toluene

    Science.gov (United States)

    Hyperbranched polymers were synthesized by using a Lewis acid (dibutyltin(IV)oxide) to catalyze the polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutaric acid (n=3) or azelaic acid (n=7) in toluene. These are the first examples of diacid-glycerol hyperbranc...

  12. NQR Zeeman effect in 2, 4, 6 tribromophenyl-p-toluene sulfonate

    International Nuclear Information System (INIS)

    NQR Zeeman effect studies in 2, 4, 6 Tribromophenyl-p-toluene Sulfonate for 79Br isotope were carried out using single crystals. The value of the asymmetry parameter and the directions of the principal field gradient X, Y, Z axes were determined. The values of the various contributions to the bond character are calculated. (auth.)

  13. Preparation of transgenic plants for phytoremediation of toluene and other pollutants.

    Czech Academy of Sciences Publication Activity Database

    Nováková, M.; Macková, M.; Chrastilová, Z.; Sylvestre, M.; Macek, Tomáš

    Olomouc : Univerzita Palackého, 2006. s. 73. [Young Scientists Symposium Future Trends in Phytochemistry . 28.06.2006-01.07.2006, Olomouc] R&D Projects: GA MŠk 1M06030 Institutional research plan: CEZ:AV0Z40550506 Keywords : phytoremediation * bacterial toluene dioxygenase * transgenic plants Subject RIV: EI - Biotechnology ; Bionics

  14. Breakthrough of toluene vapours in granular activated carbon filled packed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, N., E-mail: mohan29@yahoo.com [Defence Bio-Engineering and Electro Medical Laboratory (DEBEL), Defence R and D Organisation (DRDO), C.V.Raman Nagar, Bangalore (India); Kannan, G.K.; Upendra, S. [Defence Bio-Engineering and Electro Medical Laboratory (DEBEL), Defence R and D Organisation (DRDO), C.V.Raman Nagar, Bangalore (India); Subha, R. [Siddaganga Institute of Technology (SIT), Dept of Chem. Engg, Tumkur, Karnataka (India); Kumar, N.S. [Defence Bio-Engineering and Electro Medical Laboratory (DEBEL), Defence R and D Organisation (DRDO), C.V.Raman Nagar, Bangalore (India)

    2009-09-15

    The objective of this research was to determine the toluene removal efficiency and breakthrough time using commercially available coconut shell-based granular activated carbon in packed bed reactor. To study the effect of toluene removal and break point time of the granular activated carbon (GAC), the parameters studied were bed lengths (2, 3, and 4 cm), concentrations (5, 10, and 15 mg l{sup -1}) and flow rates (20, 40, and 60 ml/min). The maximum percentage removal of 90% was achieved and the maximum carbon capacity for 5 mg l{sup -1} of toluene, 60 ml/min flow rate and 3 cm bed length shows 607.14 mg/g. The results of dynamic adsorption in a packed bed were consistent with those of equilibrium adsorption by gravimetric method. The breakthrough time and quantity shows that GAC with appropriate surface area can be utilized for air cleaning filters. The result shows that the physisorption plays main role in toluene removal.

  15. Draft Genome Sequence of the Toluene-Degrading Pseudomonas stutzeri Strain ST-9

    OpenAIRE

    Gomila, Margarita; Busquets, Antonio; García-Valdés, Elena; Michael, Esti; Cahan, Rivka; Nitzan, Yeshayahu; Lalucat, Jorge

    2015-01-01

    Strain ST-9 was isolated from toluene-contaminated soil (Samaria, Israel). The draft genome has an estimated size of 4.8 Mb, exhibits an average G+C content of 60.37%, and is predicted to encode 4,183 proteins, including a gene cluster for aromatic hydrocarbon degradation. It is assigned to genomovar 3 of Pseudomonas stutzeri.

  16. Influence of activated carbon characteristics on toluene and hexane adsorption: Application of surface response methodology

    Science.gov (United States)

    Izquierdo, Mª Teresa; de Yuso, Alicia Martínez; Valenciano, Raquel; Rubio, Begoña; Pino, Mª Rosa

    2013-01-01

    The objective of this study was to evaluate the adsorption capacity of toluene and hexane over activated carbons prepared according an experimental design, considering as variables the activation temperature, the impregnation ratio and the activation time. The response surface methodology was applied to optimize the adsorption capacity of the carbons regarding the preparation conditions that determine the physicochemical characteristics of the activated carbons. The methodology of preparation produced activated carbons with surface areas and micropore volumes as high as 1128 m2/g and 0.52 cm3/g, respectively. Moreover, the activated carbons exhibit mesoporosity, ranging from 64.6% to 89.1% the percentage of microporosity. The surface chemistry was characterized by TPD, FTIR and acid-base titration obtaining different values of surface groups from the different techniques because the limitation of each technique, but obtaining similar trends for the activated carbons studied. The exhaustive characterization of the activated carbons allows to state that the measured surface area does not explain the adsorption capacity for either toluene or n-hexane. On the other hand, the surface chemistry does not explain the adsorption results either. A compromise between physical and chemical characteristics can be obtained from the appropriate activation conditions, and the response surface methodology gives the optimal activated carbon to maximize adsorption capacity. Low activation temperature, intermediate impregnation ratio lead to high toluene and n-hexane adsorption capacities depending on the activation time, which a determining factor to maximize toluene adsorption.

  17. The effect of MFI zeolite lamellar and related mesostructures on toluene disproportionation and alkylation.

    Czech Academy of Sciences Publication Activity Database

    Jo, Ch.; Ryoo, R.; Žilková, Nad?žda; Vitvarová, Dana; ?ejka, Ji?í

    2013-01-01

    Ro?. 3, ?. 8 (2013), s. 2119-2129. ISSN 2044-4753 R&D Projects: GA ?R(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : Adsorption measurement * Alkylation of toluene * Isopropyl alcohol s Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.760, year: 2013

  18. Preparation of transgenic plants for preferable phytoremediation of toluene and other organic pollutants.

    Czech Academy of Sciences Publication Activity Database

    Nováková, M.; Macková, M.; Sylvestre, M.; Chrastilová, Z.; Macek, Tomáš

    ?eské Bud?jovice : Scientific Pedagogical Publishing, 2006 - (?ehout, V.), s. 1035 ISBN 8085645-53-X. [Biotechnology 2006. ?eské Bud?jovice (CZ), 15.02.2006-16.02.2006] Institutional research plan: CEZ:AV0Z40550506 Keywords : toluene dioxygenase * Nicotiana benthamiana * transgenic plant Subject RIV: EI - Biotechnology ; Bionics

  19. Fluorescence spectroscopy of C 60 in toluene solutions at 5 K

    Science.gov (United States)

    Rice, James H.; Aures, Robert; Galaup, Jean-Pierre; Leach, Sydney

    2001-01-01

    We have recorded the dispersed fluorescence and the fluorescence excitation spectra of C 60 in toluene matrices at 5 K. Upon excitation with the green Ar + laser line ( ?=514 nm) we obtained for the first time in this matrix well resolved visible fluorescence spectra which we have compared with those observed in other low temperature matrices. Our spectra were interpreted and assigned using theoretical assessments of vibronic activities of transitions between the three lowest excited electronic states 1T 1g, 1T 2g, 1G g and the totally symmetric ground state, and on the basis of a single 0 0 level which has pseudo-Jahn-Teller (JT) components of the three near-degenerate excited states. The fluorescence spectra exhibit prominent JT induced h g(1) progressions, Herzberg-Teller-induced h u and other ungerade mode vibrations, including a very active t 1u(4) mode. Excitation wavelength independent bands are assigned to the fluorescence of C 60 molecules in toluene microcrystals embedded in the toluene glass whereas excitation wavelength dependent features are interpreted as originating from C 60 molecules isolated in the toluene glass itself. These interpretations are supported by the results of spectrally selective detected fluorescence excitation spectra.

  20. Pt and Au Nanostructured Materials for Catalytic Oxidation of Ethanol and Toluene.

    Czech Academy of Sciences Publication Activity Database

    Gaálová, Jana; Kaluža, Lud?k; Topka, Pavel

    2010, s. 409. ISBN N. [NANOSMAT-5. Remis (FR), 19.10.2010-21.10.2010] R&D Projects: GA ?R GPP106/10/P019 Institutional research plan: CEZ:AV0Z40720504 Keywords : catalytic oxidation * ethanol * toluene Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.nanosmat-conference.com/

  1. TOWARD COST-BENEFIT ANALYSIS OF ACUTE BEHAVIORAL EFFECTS OF TOLUENE IN HUMANS

    Science.gov (United States)

    There is increasing interest in being able to express the consequences of exposure to potentially toxic compounds in monetary terms in order to evaluate potential cost-benefit relationships of controlling exposure. Behavioral effects of acute toluene exposure could be subjected ...

  2. Compensation effect and volcano curve in toluene hydrogenation catalyzed by transition metal sulfides.

    Science.gov (United States)

    Guernalec, N; Geantet, C; Cseri, T; Vrinat, M; Toulhoat, H; Raybaud, P

    2010-09-28

    Within the framework of volcano curves, a kinetic study of toluene hydrogenation catalyzed by transition metal sulfides highlights the variation of the apparent kinetic parameters as a function of the ab initio sulfur-metal bond energy descriptor and sulfo-reductive reaction conditions. PMID:20424734

  3. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    Science.gov (United States)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-01

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  4. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  5. Start-up and Performance Characteristics of a Trickle Bed Reaktor Degrading Toluene.

    Czech Academy of Sciences Publication Activity Database

    Misiaczek, O.; Paca, J.; Halecký, M.; Gerrard, A. M.; Sobotka, Miroslav; Soccol, C. R.

    2007-01-01

    Ro?. 50, ?. 5 (2007), s. 871-877. ISSN 1516-8913 Grant ostatní: GA ?R(CZ) GA104/05/0194 Institutional research plan: CEZ:AV0Z50200510 Source of funding: V - iné verejné zdroje Keywords : biotrickling filter * constructed mixed population * toluene Subject RIV: EE - Microbiology, Virology Impact factor: 0.349, year: 2007

  6. Turbidimetric behavior of Butadiene Rubber (BR) solutions in toluene and dichloromethane after heating at open air

    International Nuclear Information System (INIS)

    This paper deals with the turbidimetric behavior of Butadiene Rubber BR solutions, a synthetic rubber, in two solvents (toluene and dichloromethane), after heating at open air till 180 Deg Celsius for optimal polymer cracking conditions. Concentration, solvent and temperature effects have been studied using methanol as precipitant. Butadiene rubber exhibits a high sensitivity to autoxidation with high tendency to reticulation.

  7. Toluene biodegradation and biofilm growth in an aerobic fixed-film reactor

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1992-01-01

    Aerobic biodegradation of toluene in a biofilm system was investigated. Toluene is easily biodegradable, like several other aromatic compounds. The degradation was first order at bulk concentrations lower than 0.14 mg/l and zero order above 6–8 mg/l. An average yield coefficient of 1 mg biomass/mg toluene degraded was found. A chemical oxygen demand balance relative to three biofilm growth scenarios showed that only a minor fraction of the carbon in the influent accumulated as biomass in the reactor. Of this accumulated biomass only a small fraction was active biomass, about 5% protein. A characterization of the carbon fractions leaving the reactor showed a significant production of soluble polymers and formation of suspended biomass. The latter was probably due to the detachment of filamentous bacteria. A decrease in toluene degradation was observed when the oxygen concentration was increased from 5 to about 20 mg/l. Future studies must show if this effect was due to inhibition.

  8. Total Oxidation of Toluene over Calcined Layered Double Hydroxides Containing Various Transition Metals.

    Czech Academy of Sciences Publication Activity Database

    Jirátová, Kv?ta; Kovanda, F.

    -, 2011, s. 345. ISBN N. [European Clay Conference EUROCLAY 2011. Antalya (TR), 26.06.2011-01.07.2011] R&D Projects: GA ?R GAP106/10/1762 Institutional research plan: CEZ:AV0Z40720504 Keywords : idh * toluene * total oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  9. Photocatalytic Oxidation Processes for Toluene Oxidation over TiO2 Catalysts

    Directory of Open Access Journals (Sweden)

    Yasutake Teraoka

    2013-03-01

    Full Text Available 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. In situ Fourier transform infrared (FTIR studies revealed that water vapor promoted the cleavage of the aromatic ring and facilitated CO2 formation. At the reaction temperature of 300 K, the deposition of Pt on TiO2 suppressed CO formation, whereas catalytic activity was decreased due to the increase in the amount of intermediate compounds. On the other hand, Pt/TiO2 showed higher activity than TiO2 at 353 K, in spite of the increase of the intermediate compounds.

  10. 40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexanoic acid, 2-ethyl-, mixed... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed... to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, mixed triesters...

  11. 40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexanoic acid, 2-ethyl-, ethenyl ester... Substances § 721.4250 Hexanoic acid, 2-ethyl-, ethenyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, ethenyl ester...

  12. Interim report: Study of benzene release from Savannah River in-tank precipitation process slurry simulant

    International Nuclear Information System (INIS)

    At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form a 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses both flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry stimulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every 3 minutes. The following 75-mL samples were measured for release rates: KTPB slurry with 15,000 ppm freshly added benzene that was gently mixed with the slurry, KTPB slurry homogenized (energetically mixed) with 15,000 ppm and 5,000 ppm benzene, clear and filtered KTPB salt solution saturated with benzene (with and without a pure benzene layer on top of the solution), and a slurry sample from a large demonstration experiment (DEMO slurry) containing-benzene generated in situ

  13. Time Dependent Gene Expression Changes in the Liver of Mice Treated with Benzene

    OpenAIRE

    Rana, S.V.S.; Seokjoo Yoon; Jung Hwa Oh; Han-Jin Park

    2008-01-01

    Benzene is used as a general purpose solvent. Benzene metabolism starts from phenol and ends with p-benzoquinone and o-benzoquinone. Liver injury inducted by benzene still remains a toxicologic problem. Tumor related genes and immune responsive genes have been studied in patients suffering from benzene exposure. However, gene expression profiles and pathways related to its hepatotoxicity are not known. This study reports the results obtained in the liver of BALB/C mice (SLC, Inc., Japan) admi...

  14. The Role of Exopolysaccharide, Biosurfactant and Peroxidase Enzymes on Toluene Degradation by Bacteria Isolated From Marine and Wastewater Environments

    Directory of Open Access Journals (Sweden)

    Afrouzossadat Hosseini Abari

    2012-08-01

    Full Text Available Background: Toluene which widely exists in petroleum and its related products has gathered much attention due to its adverse effects on health and carcinogenic potential. Since microorganisms are able to utilize petroleum hydrocarbon as carbon and energy sources, they can be used for bioremediation applications.Objectives: The aim of this study was to isolate toluene degrading bacteria from wastewater and seawater. The production of exopolysaccharide, biosurfactant and peroxidase enzymes such as laccase and catalase were investigated to determine the effect of them on toluene degradation.Materials and Methods: To screen and isolate toluene degrading bacteria, contaminated seawater and wastewater samples were added to toluene containing mineral media (MM. The biochemical and molecular characteristics of the isolates were then studied.Results: From seawater, two toluene degrading Bacillus and one Sporosacina species and from wastewater a novel high capable toluene degrading strain, Bacterium Ex-DG74 were isolated and introduced. Bacterium Ex-DG74 showed tolerance to 15 % (v/v toluene but the marine isolated species could tolerate only 1 % (v/v toluene. This bacterium also showed the highest catalase and membrane-bound laccase activity. The spore-forming marine bacterium, S. halophila produced large amounts of exopolysaccharide, biosurfactant and extracellular laccase.Conclusions: The results of the present research indicated that EPS, biosurfactant and peroxidase enzymes can have essential roles on toluene tolerance and biodegradation. These native microbial isolates could be considered as a powerful approach for the in situ bioremediation of hydrocarbon-contaminated sea and wastewater..--------------------------------------------------------------------------------Implication for health policy/practice/research/medical education:This research introduced toluene degrading bacteria as suitable strains for bioremediation of toluene contaminated water environments by the production of high amounts of exopolysaccharides, biosurfactants and peroxidase enzymes..Please cite this paper as:Hosseini Abari A, Emtiazi G, Ghasemi SM. The Role of Exopolysaccharide, Biosurfactant and Peroxidase Enzymes on Toluene Degradation by Bacteria Isolated From Marine and Wastewater Environments. Jundishapur J Mirobiol. 2012; 5(3:479-485. DOI: 10.5812/jjm.3554.

  15. 40 CFR 721.1193 - Benzene, 2-bromo-1,4-dimethoxy-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 2-bromo-1,4-dimethoxy-. 721... Substances § 721.1193 Benzene, 2-bromo-1,4-dimethoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, 2-bromo-1,4-dimethoxy- (PMN...

  16. Rapid Benzene Degradation in Methanogenic Sediments from a Petroleum-Contaminated Aquifer

    OpenAIRE

    Weiner, Jonathan M.; Derek R. Lovley

    1998-01-01

    In methanogenic sediments from a petroleum-contaminated aquifer, [14C]benzene was converted to 14CH4 and 14CO2 without an apparent lag. Phenol, acetate, and propionate were intermediates in benzene mineralization. These results suggest that alternative electron acceptors need not be available for there to be significant natural attenuation of benzene in some petroleum-contaminated aquifers.

  17. Effect of vehicle on brain uptake of [11C]toluene

    International Nuclear Information System (INIS)

    With the goal of investigating the pharmacokinetics of the abused solvent, toluene we have adapted the rapid coupling of methyl iodide with tributylphenylstannane mediated by palladium(0) complex to the synthesis of no-carrier-added [11C]toluene starting with 11CH3I. Two methods for purification and formulation of the tracer were developed. The first one yielded [11C]toluene dissolved in dimethylacetamide/saline solution, for the second one we adapted supercritical fluid technology where the tracer was purified using and conventional C18 HPLC column and pure supercritical CO2 fluid as a mobile phase operating at 2000 psi. Formulation of the tracer in cyclodextrin resulted in a significantly higher integrated uptake and distribution volume values. Additionally, we observed higher uptake and slower clearance of 11C-toluene in white matter, consistent with higher lipid content and neurotoxicological evidence indicating restricted and diffuse white matter changes in toluene abusers. This trend was observed when either DMA or cyclodextrin was used as a vehicle. It appears then, that the choice of a vehicle affected only the degree of bioavailability, but not the regional brain pharmacokinetics. Finally, we demonstrated the effect of a decreased percent difference between DV values for the studies performed on the same day, that is, test/retest variability was lower for all brain regions in ?-cyclodextrin experiments. Present results clearly demonstrate that the choice of a vehicle has a significant effect on tracer uptake and should be considered as a potential factor contributing to the pharmacokinetic measurements

  18. Picosecond spectral relaxation of curcumin excited state in toluene–alcohol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Saini, R.K.; Das, K., E-mail: kaustuv@rrcat.gov.in

    2013-12-15

    Excited state photophysics of Curcumin in a binary solvent mixture of toluene and five different alcohols (Methanol, Ethanol, 1-Propanol, 1-Butanol and 1-Octanol) are compared with an instrument time resolution of ?40 ps. As the alcohol mole-fraction is varied from zero to unity, the observed trends in the fluorescence quantum yield and lifetime of the pigment in toluene–alcohol mixtures changes significantly in going from Methanol to 1-Octanol. This is attributed to the different degree of modulation of the non-radiative rates associated with the excited state intermolecular H bonding between the pigment and the alcohol. Fluorescence decays taken at the red edge of the emission spectrum started to show measurable rise times (200–30 ps) the magnitude of which decreased gradually with increasing alcohol mole-fraction. As a consequence the solvation times in the binary mixture were observed to slow down considerably at certain solvent compositions compared to that in neat alcohol. However, in toluene-1-Octanol mixture, the rise times and corresponding solvation times did not show a dependence on the 1-Octanol mole-fraction. The observed results suggest that viscosity, polarity and hydrogen bonding property of the alcohol solvent plays an important role in the excited state processes of the pigment in toluene–alcohol mixture. -- Highlights: • Excited state photophysics of Curcumin in a binary solvent mixture of toluene and five different alcohols were studied. • The observed trends in the fluorescence properties are attributed to intermolecular H bonding between the pigment and the alcohol. • Except 1-Octanol, the average solvation times of the pigment were observed to depend upon alcohol mole-fraction. • Viscosity, polarity and hydrogen bonding play an important role in the excited state processes of the pigment.

  19. Study of the solubility of kerogen from oil shales (Puertollano, Spain) in supercritical toluene and methanol

    Energy Technology Data Exchange (ETDEWEB)

    M. Luisa G.-Hourcade; Carmen Torrente; Miguel Angel Galan [University of Salamanca, Salamanca (Spain). Department of Chemical Engineering

    2007-03-15

    In mixtures of bitumen-toluene and bitumen-methanol, supercritical equilibrium compositions were measured at 603.15, 613.15, 623.15 and 633.15 K (reduced temperatures 1.02, 1.04, 1.05 and 1.07) in a range of pressures of 4.5-14.5 MPa for toluene as solvent, and at 553.15; 583.15; 613.15 and 623.15 K (reduced temperatures 1.08, 1.14, 1.18 and 1.21) and pressures from 6.5 to 22.5 MPa for methanol as solvent. The solubility data were correlated by using Chrastil equation. At each temperature the number of molecules of solvent per molecule of solute was calculated for both toluene and methanol. Association numbers between 1.67 {+-} 0.02 and 2.47 {+-} 0.08 were obtained for toluene and 2.36 {+-} 0.10 and 2.60 {+-} 0.08 for methanol. In conclusion, association number was not independent of temperature. Also density data calculated with some equations of state (Peng-Robinson, Soave-Redlich-Kwong and Lee-Kesler) were compared to empirical density data in order to determine the effect of using any of them. Compounds obtained with each of solvents were analyzed using gas chromatography with a mass detector. Results obtained indicate that toluene extracts mainly aromatic compounds and little of paraffin and depletes the organic material in the oil shale. On the other hand with methanol lineal hydrocarbons insaturated and saturated with very little of aromatic compounds were obtained. This indicates that some reaction products are probably produced during the extraction process. 20 refs., 8 figs., 10 tabs.

  20. Trinexapac-ethyl e adubação nitrogenada na cultura do trigo / Trinexapac-ethyl and nitrogen fertilization rates in wheat crop

    Scientific Electronic Library Online (English)

    E.E., Pagliosa; G., Benin; E., Biezus; E., Beche; C.L., Silva; J.A., Marchese; T.N., Martin.

    2013-09-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de doses do regulador de crescimento trinexapac-ethyl e níveis de adubação nitrogenada sobre o desempenho agronômico e rendimento de grãos de três cultivares de trigo. O delineamento experimental foi de blocos ao acaso, em esquema fatorial, com três rep [...] etições, sendo: duas doses de adubação nitrogenada (60 e 120 kg ha-1), três cultivares de trigo (BRS 208, BRS 220 e BRS Guamirim), quatro doses de trinexapac-ethyl (0, 70, 140 e 210 g i.a. ha-1) e duas safras agrícolas (2008 e 2009). Na microrregião de Pato Branco, a dose de 60 kg ha-1 é suficiente para maximizar o potencial de rendimento de grãos dos cultivares avaliados. Independentemente da estatura dos cultivares, o regulador de crescimento não apresentou efeito positivo sobre o rendimento de grãos, com efeito negativo na presença de menor disponibilidade hídrica. Abstract in english The objective of this work was to evaluate the effect of trinexapac-ethyl and nitrogen doses on the agronomic performance and grain yield of three wheat cultivars. The experiment was arranged in a randomized block design in a factorial scheme, with three replications. The treatments were two nitroge [...] n fertilization doses (60 and 20 kg ha-1), three wheat cultivars (BRS 208, BRS 220, and BRS Guamirim), four trinexapac-ethyl doses (0, 70, 140, and 210 g a.i. ha-1) and two harvest years (2008 and 2009). In the Pato Branco microregion, the nitrogen rate of 60 kg ha-1 was sufficient to maximize the yield potential of the evaluated cultivars. Regardless of the height of the cultivar plants, trinexapac-ethyl showed no positive effect on grain yield, with negative effect under water-deficit stress.

  1. Infrared spectra of scandium triiodide in benzene solution

    International Nuclear Information System (INIS)

    Infrared spectrum of scandium triiodide in benzene solution was studied within the range of wavelengths 180-450 cm-1. It is found that bands with maxima at 301, 280 and 225 cm-1 are assigned to dimer and the band at 265 cm-1 to monomer of scandium triiodide. Refs. 7, figs. 1, tabs. 1

  2. [A case of occupational benzene poisoning combined with tricholeukocytic leukemia].

    Science.gov (United States)

    Bescol-Liversac, J; Chabaux, C; Bolinard, S; Guillam, C

    1982-11-01

    Case report of occupational intoxication, with moderate anemia and hypogranulocytosis, in the course of which occurs a hairy cell leukemia. Cytological data are significative in photonic and electronic microscopy: microvilli and granulo-lamellar complexes. Discussion of benzen, as toxic factor in etiology of this leukemia. PMID:7170726

  3. Deuterium isotope effects on toluene metabolism. Product release as a rate-limiting step in cytochrome P-450 catalysis

    International Nuclear Information System (INIS)

    Liver microsomes from phenobarbital-induced rats oxidize toluene to a mixture of benzyl alcohol plus o-, m- and p-cresol (ca. 69:31). Stepwise deuteration of the methyl group causes stepwise decreases in the yield of benzyl alcohol relative to cresols (ca. 24:76 for toluene-d3). For benzyl alcohol formation from toluene-d3 DV = 1.92 and D(V/K) = 3.53. Surprisingly, however, stepwise deuteration induces stepwise increases in total oxidation, giving rise to an inverse isotope effect overall (DV = 0.67 for toluene-d3). Throughout the series (i.e. d0, d1, d2, d3) the ratios of cresol isomers remain constant. These results are interpreted in terms of product release for benzyl alcohol being slower than release of cresols (or their epoxide precursors), and slow enough to be partially rate-limiting in turnover. Thus metabolic switching to cresol formation causes a net acceleration of turnover

  4. Influence of toluene contamination at the hydrogen Pt/C anode in a proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    For fuel cells run on hydrogen reformate, traces of hydrocarbon contaminants in the hydrogen gas may be a concern for the performance and lifetime of the fuel cell. This study focuses on the influence of low concentrations of toluene on the adsorption and deactivation chemistry in a proton exchange membrane (PEM) fuel cell. For this purpose cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques were employed. Results from adsorption and desorption (by oxidation or reduction) experiments performed in a humidified nitrogen or hydrogen flow in a fuel cell test cell with a mass spectrometer system connected to the outlet are presented. The influence of adsorption potential, temperature, and humidity are discussed. The results show that toluene adsorbs on the catalyst surface in a broad potential window, up to at least 0.85 V versus RHE at 80 oC. Adsorbed toluene oxidizes to CO2 with peak potentials above 1.0 V for temperatures below 95 oC. Some desorption of toluene (or reduced products) may take place at potentials below 0 V. In a hydrogen flow, toluene contamination in per mille concentrations leads to a continuous growth of the charge transfer resistance, while a 10-fold dilution of the toluene concentration resulted in a low and constant charge transfer resistance even for longer exposures. This indicates that a competition between toluene and hydrogen may take place on the active platinum surface at the anode.

  5. Theoretical and kinetic study of the hydrogen atom abstraction reactions of ethyl esters with hydrogen radicals

    Science.gov (United States)

    Wang, Quan-De; Wang, Xing-Jian; Liu, Zi-Wu; Kang, Guo-Jun

    2014-11-01

    Ab initio and chemical kinetic study of the hydrogen abstraction reactions by the hydrogen radical on ethyl formate, ethyl acetate, ethyl propanoate, and ethyl butanoate have been performed at the CCSD(T)/CBS//B3LYP/6-311G(d, p) level of theory. High-pressure limit rate constants at temperatures from 300 to 2500 K have been calculated for all of the reaction channels using transition state theory with Eckart tunneling corrections, and the data are fitted to the modified three parameters Arrhenius expression using least-squares regression. A branching ratio analysis for each reaction site has also been investigated for all of the ethyl esters.

  6. Optical on-line method of ethyl mercaptan detection in liquid phase in motor fuels

    Science.gov (United States)

    Kireev, S. V.; Shnyrev, S. L.

    2015-11-01

    The letter reports on the experimental research of the absorption spectra of ethyl mercaptan in liquid phase in various motor fuels (petrol, kerosene, and diesel fuel). The values of ethyl mercaptan absorption sections were obtained in the above-mentioned fuels in the spectral range of 280–475?nm, and the dependences of ethyl mercaptan absorption coefficients on its part in the analyzed mixture with motor fuels were researched. On the basis of the obtained results we propose an optical on-line method of ethyl mercaptan detection in motor fuels. The optimal spectral ranges for the highest sensitivity of ethyl mercaptan detection in various motor fuels were determined.

  7. Preparative-scale separation of ethyl esters of diethylenetriaminepentaacetic acid by flash chromatography

    International Nuclear Information System (INIS)

    The penta ethyl ester of diethylenetriamine pentaacetic acid (DTPA) can be used as a prodrug for decorporation of radionuclides in the event of an internal radiation incidents with transuranic elements. A C18 chromatography purification method was successfully developed using a step elution profile to isolate 0.5-3 g of the four ethyl esters of DTPA. Less than 11 % of the isolated di-ethyl and tri-ethyl esters of DTPA, and less than 20 % of the tetra-ethyl ester of DTPA, had degraded in phosphate buffered saline over a 168 h period. (author)

  8. Biodegradation of ortho-Cresol by a Mixed Culture of Nitrate-Reducing Bacteria Growing On Toluene

    DEFF Research Database (Denmark)

    Flyvbjerg, John; JØrgensen, Claus

    1993-01-01

    A mixed culture of nitrate-reducing bacteria degraded o-cresol in the presence of toluene as a primary growth substrate. No degradation of o-cresol was observed in the absence of toluene or when the culture grew on p-cresol and 2,4-dimethylphenol. In batch cultures, the degradation of o-cresol started after toluene was degraded to below 0.5 to 1.0 mg/liter but continued only for about 3 to 5 days after the depletion of toluene since the culture had a limited capacity for o-cresol degradation once toluene was depleted. The total amount of o-cresol degraded was proportional to the amount of toluene metabolized, with an average yield of 0.47 mg of o-cresol degraded per mg of toluene metabolized. Experiments with (ring-U-14C)o-cresol indicated that about 73% of the carbon from degraded o-cresol was mineralized to CO-2 and about 23% was assimilated into biomass after the transient accumulation of unidentified water-soluble intermediates. A mathematical model based on a simplified Monod equation is used to describethe kinetics of o-cresol degradation. In this model, the biomass activity toward o-cresol is assumed to decay according to first-order kinetics once toluene is depleted. On the basis of nonlinear regression of the data, the maximum specific rate of o-cresol degradation was estimated to be 0.4 mg of o-cresol per mg of biomass protein per h, and the first-order decay constants for o-cresol-degrading biomass activity was estimated to be 0.15 h-1. We hypothesize that the mixed culture degrades o-cresol by a cometabolic mechanism in which the enzymes necessary for the degradation of o-cresol are induced by toluene and not by o-cresol.

  9. Stratospheric benzene and hydrocarbon aerosols detected in Saturn's auroral regions

    Science.gov (United States)

    Guerlet, S.; Fouchet, T.; Vinatier, S.; Simon, A. A.; Dartois, E.; Spiga, A.

    2015-08-01

    Context. Saturn's polar upper atmosphere exhibits significant auroral activity; however, its impact on stratospheric chemistry (i.e. the production of benzene and heavier hydrocarbons) and thermal structure remains poorly documented. Aims: We aim to bring new constraints on the benzene distribution in Saturn's stratosphere, to characterize polar aerosols (their vertical distribution, composition, thermal infrared optical properties), and to quantify the aerosols' radiative impact on the thermal structure. Methods: Infrared spectra acquired by the Composite Infrared Spectrometer (CIRS) on board Cassini in limb viewing geometry are analysed to derive benzene column abundances and aerosol opacity profiles over the 3 to 0.1 mbar pressure range. The spectral dependency of the haze opacity is assessed in the ranges 680-900 and 1360-1440 cm-1. Then, a radiative climate model is used to compute equilibrium temperature profiles, with and without haze, given the haze properties derived from CIRS measurements. Results: On Saturn's auroral region (80°S), benzene is found to be slightly enhanced compared to its equatorial and mid-latitude values. This contrasts with the Moses & Greathouse (2005, J. Geophys. Res., 110, 9007) photochemical model, which predicts a benzene abundance 50 times lower at 80°S than at the equator. This advocates for the inclusion of ion-related reactions in Saturn's chemical models. The polar stratosphere is also enriched in aerosols, with spectral signatures consistent with vibration modes assigned to aromatic and aliphatic hydrocarbons, and presenting similarities with the signatures observed in Titan's stratosphere. The aerosol mass loading at 80°S is estimated to be 1-4 × 10-5 g cm-2, an order of magnitude less than on Jupiter, which is consistent with the order of magnitude weaker auroral power at Saturn. We estimate that this polar haze warms the middle stratosphere by 6 K in summer and cools the upper stratosphere by 5 K in winter. Hence, aerosols linked with auroral activity can partly account for the warm polar hood observed in Saturn's summer stratosphere.

  10. Mass spectrometric study of the high temperature chemistry of benzene

    International Nuclear Information System (INIS)

    The high temperature pyrolysis of benzene was studied by monitoring the gas phase species flowing from a Knudsen reaction cell using modulated molecular beam mass spectrometry. The pyrolysis was studied at temperatures up to 19000C and pressures to 5 Torr. At low pressures hydrogen and carbonaceous deposits (soot) on the reaction cell wall were the dominant products. The disappearance of benzene at the low pressure limit was found to have an apparent activation energy of 82 +- 5 kcal/mole. The rate of carbon formation was determined indirectly from the difference between carbon from benzene flow into the reactor and products leaving the reactor, and good agreement was noted for carbon recovered from the reactor for extended experiments at 16000C. Carbon deposition is most efficient at low pressures; carbon deposition increases with pressure but the fraction of deposited carbon decreases as gas phase reactions become important. At higher pressures, where gas phase reactions dominate, C2H2, C4H2, C6H2, C8H6, C12H10, C12H8, H2, and carbon were the major products. The results suggest that the pyrolysis of benzene primarily involves the reaction of an excited benzene molecule to form a C12H12 intermediate which decomposes to yield C12H10 and other products. Isotopic exchange in C6H6-D2 and C6H6-C6D6 mixtures occurs at the same temperature as biomolecular reaction. At temperatures greater than 11000C more direct processes involving C6H4 appear to contribute. The pyrolysis occurs primarily by molecular processes, possibly due to the effects of wall-related reactions. 41 references, 16 figures, 1 table

  11. Physiologically based pharmacokinetic modeling of ethyl acetate and ethanol in rodents and humans.

    Science.gov (United States)

    Crowell, S R; Smith, J N; Creim, J A; Faber, W; Teeguarden, J G

    2015-10-01

    A physiologically based pharmacokinetic (PBPK) model was developed and applied to a metabolic series approach for the ethyl series (i.e., ethyl acetate, ethanol, acetaldehyde, and acetate). This approach bases toxicity information on dosimetry analyses for metabolically linked compounds using pharmacokinetic data for each compound and toxicity data for parent or individual compounds. In vivo pharmacokinetic studies of ethyl acetate and ethanol were conducted in rats following IV and inhalation exposure. Regardless of route, ethyl acetate was rapidly converted to ethanol. Blood concentrations of ethyl acetate and ethanol following both IV bolus and infusion suggested linear kinetics across blood concentrations from 0.1 to 10 mM ethyl acetate and 0.01-0.8 mM ethanol. Metabolic parameters were optimized and evaluated based on available pharmacokinetic data. The respiratory bioavailability of ethyl acetate and ethanol were estimated from closed chamber inhalation studies and measured ventilation rates. The resulting ethyl series model successfully reproduces blood ethyl acetate and ethanol kinetics following IV administration and inhalation exposure in rats, and blood ethanol kinetics following inhalation exposure to ethanol in humans. The extrapolated human model was used to derive human equivalent concentrations for the occupational setting of 257-2120 ppm ethyl acetate and 72-517 ppm ethyl acetate for continuous exposure, corresponding to rat LOAELs of 350 and 1500 ppm. PMID:26297692

  12. Neutral and cationic chiral NCN pincer nickel(II) complexes with 1,3-bis(2'-imidazolinyl)benzenes: synthesis and characterization.

    Science.gov (United States)

    Shao, Dan-Dan; Niu, Jun-Long; Hao, Xin-Qi; Gong, Jun-Fang; Song, Mao-Ping

    2011-09-21

    Chiral 1,3-bis(2'-imidazolinyl)benzenes 1a-e easily undergo direct nickelation at the C2 position of the central benzene ring via the C-H bond activation in the reaction with anhydrous NiCl(2) giving neutral NCN pincer nickel(II) complexes 2a-e in 40-87% yields. Treatment of the nickel pincers 2a or 2c with AgBF(4) in CH(3)CN-CH(2)Cl(2) afforded the cationic nickel pincers 3a or 3c in good yields. All the complexes were characterized by elemental analysis, (1)H, (13)C NMR, and IR spectra. Molecular structures of the neutral complexes 2a, 2b and 2c as well as the cationic complex 3c have been determined by X-ray single-crystal diffraction. The cationic nickel pincers 3 are found to be effective catalysts for the Michael addition of ethyl 2-cyanopropionate to methyl vinyl ketone in the presence of i-Pr(2)NEt base with a catalyst loading of 5 mol% even at -78 °C, producing the adduct in >99% yield after 24 h albeit with no ee. PMID:21691647

  13. Formation of D and H atoms in the pyrolysis of benzene-d6 and chlorobenzene behind shock waves

    International Nuclear Information System (INIS)

    From the measurements of H atoms during pyrolysis of chlorobenzene under similar conditions at 1570-1790K, the first-order rate constant for the dissociation of chlorobenzene to chlorine atoms and phenyl radicals was found to be about an order of magnitude greater than that for the pyrolysis of C6D6, and a rate constant still another order of magnitude greater was noted for the dissociation of phenyl radicals to H atoms and other products. From this information, a rate constant was derived for the dissociation of benzene-d6 to phenyl-d5 and D atoms. The rate constant for the H-D exchange reaction on benzene was determined over the temperature range of 300-1400K by combining results of this work with that of others at lower temperatures. A very simple kinetic model based on a reaction chain with H as carrier can relate the data presented from this work to other shock-tube work at higher benzene concentrations

  14. Tris{2-[(2-aminobenzylideneamino]ethyl}amine

    Directory of Open Access Journals (Sweden)

    Perla Elizondo Martínez

    2010-12-01

    Full Text Available The title Schiff base, C27H33N7, is a tripodal amine displaying C3 symmetry, with the central tertiary N atom lying on the threefold crystallographic axis. The N—CH2—CH2—N conformation of the pendant arms is gauche [torsion angle = 76.1?(3°], which results in a claw-like molecule, with the terminal aniline groups wrapped around the symmetry axis. The lone pair of the apical N atom is clearly oriented inwards towards the cavity, and should thus be chemically inactive. The amine NH2 substituents lie in the plane of the benzene ring to which they are bonded. With such an arrangement, one amine H atom forms an S(6 motif through a weak N—H...N hydrogen bond with the imine N atom, while the other is engaged in an intermolecular N—H...? contact involving the benzene ring of a neighbouring molecule related by inversion. The benzene rings also participate in an intramolecular C—H...? contact of similar strength. In the crystal structure, molecules are separated by empty voids (ca 5% of the crystal volume, although the crystal seems to be unsolvated.

  15. Study of benzene release from Savannah River in-tank precipitation process slurry simulant

    International Nuclear Information System (INIS)

    At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry simulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every minute

  16. The state of benzene in TIP slurry using nuclear magnetic resonance measurements

    International Nuclear Information System (INIS)

    Nuclear Magnetic Resonance (NMR) measurements on In-Tank Precipitation (ITP) simulated potassium tetraphenylborate (KTPB) slurries at Pacific Northwest National Laboratory have been completed. Most measurements were made on 4 wt percent KTPB slurry in 4 to 5 molar sodium salt solution. Liquid benzene was added volumetrically to the slurry in 25-mL vials and agitated to create a suspension. Earlier tests using dyed benzene showed that benzene remains suspended permanently in the slurry and the only visible change is overall slurry settling. Gentle vial agitation restores the original suspension state. To simulate in-situ uniformly dispersed benzene, benzene/KTPB samples were homogenized using a high speed rotor/stator biological homogenizer. Photomicrographs using homogenized samples containing dyed benzene showed no residual benzene droplets and fairly uniform coloration of the KTPB solids structure. All benzene concentration estimates are based on benzene addition since there is no available analytical method for benzene in slurry. Benzene losses could be significant, particularly at low concentrations and during homogenization

  17. Elevated plasma creatinine due to creatine ethyl ester use.

    Science.gov (United States)

    Velema, M S; de Ronde, W

    2011-02-01

    Creatine is a nutritional supplement widely used in sport, physical fitness training and bodybuilding. It is claimed to enhance performance. We describe a case in which serum creatinine is elevated due to the use of creatine ethyl esther. One week after withdrawal, the plasma creatinine had normalised. There are two types of creatine products available: creatine ethyl esther (CEE) and creatine monohydrate (CM). Plasma creatinine is not elevated in all creatine-using subjects. CEE , but not CM, is converted into creatinine in the gastrointestinal tract. As a result the use of CEE may be associated with elevated plasma creatinine levels. Since plasma creatinine is a widely used marker for renal function, the use of CEE may lead to a false assumption of renal failure. PMID:21411845

  18. Biological monitoring of workers exposed to benzene in the coke oven industry.

    Science.gov (United States)

    Drummond, L; Luck, R; Afacan, A S; Wilson, H K

    1988-01-01

    Workers in the coke oven industry are potentially exposed to low concentrations of benzene. There is a need to establish a well validated biological monitoring procedure for low level benzene exposure. The use of breath and blood benzene and urinary phenol has been explored in conjunction with personal monitoring data. At exposures of about 1 ppm benzene, urinary phenol is of no value as an indicator of uptake/exposure. Benzene in blood was measured by head space gas chromatography but the concentrations were only just above the detection limit. The determination of breath benzene collected before the next shift is non-specific in the case of smokers. The most useful monitor at low concentrations appears to be breath benzene measured at the end-of-shift. PMID:3378002

  19. Experimental study of removing benzene from indoor air by needle-matrix to plate streamer discharge

    International Nuclear Information System (INIS)

    The degradation of benzene by needle-matrix to plate streamer discharge was investigated at normal temperature and pressure in indoor air. The effects of benzene initial concentration, air speed, discharge power and relative humidity (RH) on benzene removal rate were systematically studied. Meanwhile, the benzene removal efficiencies by adding MnO2/SiO2-active carbon catalyst to the system were also studied. The results showed that the benzene removal rate increased with the rise of the air speed and discharge power, decreased with the rise of the benzene initial concentration, and firstly increased and then decreased with the rise of the of RH. Under the same experimental conditions, adding MnO2 catalyst to the system did not significantly improve the removal efficiency of benzene.

  20. Supplementary measurements for air monitoring under NOVANA - Benzene and PAH; Supplerende maalinger til luftovervaagning under NOVANA - benzen og PAH

    Energy Technology Data Exchange (ETDEWEB)

    Ellermann, T.; Klenoe Noejgaard, J.; Bossi, R.

    2011-10-15

    The report presents results from a project carried out for the Danish Environmental Protection Agency. The aim of the project was to carry out several measuring campaigns in order to be able to better assess the monitoring needs for PAH and benzene in relation to EU's air quality directives. The results show that the mean concentrations of benzene are almost at the same level in Denmark's four largest cities, and that the concentrations are both below the threshold value (5mug/m3) as well as below the lower assessment threshold (2mug/m3). The report presents a method for objectively estimation the benzene concentration based on measurements of CO. The method can be applied to fulfil the monitoring need for benzene in those zones where no measurements of benzene are made. Measurements of PAH, especially benzo(a)pyrene, have been made during 12 months in the period 2010-2011 in an area with many wood burning furnaces are used (the town Jyllinge). The concentrations of benzo(a)pyrene in Jyllinge is almost three times higher than in the street H.C. Andersens Boulevard in Copenhagen. The concentrations of benzo(a)pyrene in Jylllinge are 0,6 ng/m3, which corresponds to the upper assessment threshold (0,6 ng/m3) and is 40% below the measuring value (1 ng/m3). On this basis, there is a need for re-evaluating the monitoring of PAH in the sub-programme for air under NOVANA. Measurements of PM{sub 10} showed that the levels in the towns Jyllinge, Lille Valby/Risoe and at the H.C. Oersted Institute in Copenhagen are all at about 20-22 mug/m3. (LN)

  1. EFFECT OF HUMIDITY IN ETHYL CELLULOSE (EC) THERMELECTRET

    OpenAIRE

    M. S. GAUR; RAMLAL; PRASHANT SHUKLA; P.K. Khare

    2008-01-01

    The ethyl cellulose samples of thickness 30 urn were prepared using solution grown method. The samples were polarized by means of thermal polarization for preparation of thermoelectret. The charge storage stability and the transport of detrapped charges in the EC thermoelectre were investigated by surface potential decay and open-circuit thermally stimulated discharge current (TSDC) analysis. The mean penetration depth for EC at different environment humidity and polarizing temperature were c...

  2. Photochemical degradation of pyrazosulfuron-ethyl in aqueous solution

    Scientific Electronic Library Online (English)

    Yanhui, Wang; Liangwei, Du; Lianyang, Bai.

    2013-01-01

    Full Text Available Este trabalho descreve o comportamento fotoquímico do pirazosulfuronato de etila em soluções aquosas. A fotodegradação do pirazosulfuronato de etila foi investigada pela primeira vez em dois comprimentos de onda de irradiação diferentes e valores de pH variando de 2,00 a 10,00. Os resultados mostram [...] que a taxa de fotodegradação foi mais rápida em meio ácido do que em meio básico, quando pyrazosulfuron-etil estava na forma neutra. Os tempos de meia-vida do pirazosulfuronato de etila sob luz ultravioleta e luz solar simulada foram 27,17 e 153,33 min, respectivamente. As reações seguiram cinética de primeira ordem. As rotas de degradação foram propostas de acordo com os resultados de identificação dos fotoprodutos: clivagens carbono-enxofre e nitrogênio-enxofre e fotohidrólise da ponte de sulfonilureia. Concluiu-se que comportamentos de fotodegradação podem ocorrer dentro da família de sulfonilureia, dependendo dos valores de pH da solução aquosa e dos comprimentos de onda de irradiação. Abstract in english This report describes photochemical behaviors of pyrazosulfuron-ethyl in aqueous solution. The photodegradation of pyrazosulfuron-ethyl for the first time was investigated in aqueous solution at two different irradiation wavelengths and pH values ranging from 2.00 to 10.00. Results show that the rat [...] e of photodegradation was faster in acidic medium than that in basic medium, when pyrazosulfuron-ethyl was in neutral form. The half-lives of pyrazosulfuron-ethyl under ultra-violet light and simulated sunlight were found to be 27.17 and 153.33 min, respectively. The reactions followed first-order kinetics. The degradation pathways were proposed according to the identification results of photoproducts: carbon-sulfur and nitrogen-sulfur cleavages and photohydrolysis of the sulfonylurea bridge. It was concluded that photodegradation behaviors can occur within the sulfonylurea family, depending on the pH values of aqueous solution and the irradiation wavelengths.

  3. Synthesis of new radiotracers based of Ethyl Ester

    International Nuclear Information System (INIS)

    The in vivo study of a biochemical or physiological process requires the synthesis of specific radiotracers but also the targeting of these compounds so that they can reach their target tissue. Methodologies original synthesis associated with radioisotopes used, the quantities and chemical forms often have to be available developed. The chemistry of metal complexes booming, we were able to use the ethyl ester combined with technetium, forming a stable radiotracer. Finally, a counting of radioactivity in different rat's organs completed our study. (Author)

  4. Ethyl cyanide on Titan: Spectroscopic detection and mapping using ALMA

    OpenAIRE

    Cordiner, M. A.; Palmer, M. Y.; Nixon, C.A.; Irwin, P G J; Teanby, N.A.; Charnley, S. B; Mumma, M. J.; Kisiel, Z.; Serigano, J.; Kuan, Y.-J.; Chuang, Y.-L.; Wang, K. -S.

    2014-01-01

    We report the first spectroscopic detection of ethyl cyanide (C$_2$H$_5$CN) in Titan's atmosphere, obtained using spectrally and spatially resolved observations of multiple emission lines with the Atacama Large Millimeter/submillimeter array (ALMA). The presence of C$_2$H$_5$CN in Titan's ionosphere was previously inferred from Cassini ion mass spectrometry measurements of C$_2$H$_5$CNH$^+$. Here we report the detection of 27 rotational lines from C$_2$H$_5$CN (in 19 separat...

  5. Sensory reception of the primer pheromone ethyl oleate

    Science.gov (United States)

    Muenz, Thomas S.; Maisonnasse, Alban; Plettner, Erika; Le Conte, Yves; Rössler, Wolfgang

    2012-05-01

    Social work force distribution in honeybee colonies critically depends on subtle adjustments of an age-related polyethism. Pheromones play a crucial role in adjusting physiological and behavioral maturation of nurse bees to foragers. In addition to primer effects of brood pheromone and queen mandibular pheromone—both were shown to influence onset of foraging—direct worker-worker interactions influence adult behavioral maturation. These interactions were narrowed down to the primer pheromone ethyl oleate, which is present at high concentrations in foragers, almost absent in young bees and was shown to delay the onset of foraging. Based on chemical analyses, physiological recordings from the antenna (electroantennograms) and the antennal lobe (calcium imaging), and behavioral assays (associative conditioning of the proboscis extension response), we present evidence that ethyl oleate is most abundant on the cuticle, received by olfactory receptors on the antenna, processed in glomeruli of the antennal lobe, and learned in olfactory centers of the brain. The results are highly suggestive that the primer pheromone ethyl oleate is transmitted and perceived between individuals via olfaction at close range.

  6. The use of biofilters to improve indoor air quality: the removal of toluene, TCE, and formaldehyde.

    Science.gov (United States)

    Darlington, A; Dixon, M A; Pilger, C

    1998-01-01

    A biofilter composed of a scrubber, a hydroponic planting system, and an aquatic system with green plants as a base maintained air quality within part of a modern office building. The scrubber was composed of five parallel fiberglass modules with external faces of porous lava rock. The face, largely covered with mosses, was wetted by recirculating water. Air was drawn through the scrubber and the immediately adjacent hydroponic region by a dedicated air handling system. The system was challenged for 4 weeks with three common indoor organic pollutants and removed significant amounts of all compounds. A single pass through the scrubber removed 10% of the trichloroethylene and 50% of the toluene. A single pass lowered formaldehyde air concentrations to 13 micrograms m-3 irrespective of influent levels (ranging between 30 and 90 micrograms m-3). The aquatic system accumulated trichloroethylene but neither toluene nor formaldehyde, suggesting the rapid breakdown of these materials. The botanical components removed some pollutants. PMID:11540466

  7. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    Directory of Open Access Journals (Sweden)

    Rajagopal K.

    2004-01-01

    Full Text Available The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10-6 g/ml and 10-7 g/ml. Sizes was measured for a period of about 10000 minutes at a constant temperature of 20°C. We found that the average size of the particles remained constant with time and increase with an increase in amount of n-heptane. The correlation obtained for size with concentration will be useful in asphaltene precipitation models.

  8. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    Scientific Electronic Library Online (English)

    K., Rajagopal; S. M. C., Silva.

    2004-12-01

    Full Text Available The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scatterin [...] g technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10-6 g/ml and 10-7 g/ml. Sizes was measured for a period of about 10000 minutes at a constant temperature of 20°C. We found that the average size of the particles remained constant with time and increase with an increase in amount of n-heptane. The correlation obtained for size with concentration will be useful in asphaltene precipitation models.

  9. Study of toluene stability for an Organic Rankine Cycle (ORC) space-based power system

    Science.gov (United States)

    Havens, Vance; Ragaller, Dana

    1988-01-01

    The design, fabrication, assembly, and endurance operation of a dynamic test loop, built to evaluate the thermal stability of a proposed Organic Rankine Cycle (ORC) working fluid, is discussed. The test fluid, toluene, was circulated through a heater, simulated turbine, regenerator, condenser and pump to duplicate an actual ORC system. The maximum nominal fluid temperature, 750 F, was at the turbine simulator inlet. Samples of noncondensible gases and liquid toluene were taken periodically during the test. The samples were analyzed to identify the degradation products formed and the quantity of these products. From these data it was possible to determine the degradation rate of the working fluid and the generation rate of noncondensible gases. A further goal of this work was to relate the degradation observed in the dynamic operating loop to degradation obtained in isothermal capsule tests. This relationship was the basis for estimating the power loop degradation in the Space Station Organic Rankine Cycle system.

  10. Decomposition of gaseous toluene using a continuous flow discharge plasma reactor with new configurations.

    Science.gov (United States)

    Liu, Juanjuan; Wang, Jingting; Cao, Xu; Zhang, Renxi; Hou, Huiqi

    2015-12-01

    The destruction of gaseous toluene was carried out in a tubular multilayer dielectric barrier discharge reactor which can yield a steady state of low-temperature plasma with an array structure. The research was investigated under different relative humidities, input voltages, energy densities, energy consumption and the reactor processing capacities. The results showed that the highest removal efficiency and processing capacity (?) were acquired using an additional dielectric with the width of 2?mm between adjacent discharge quartz tubes, and the removal efficiency of toluene reached 86.5% and ? increased to 6272?kg/s?m(3) at a voltage of 6?kV. The gas-phase by-products (O3, NOx, COx and intermediate organics) were also presented and the reaction mechanism was described according to the decomposition reaction tunnels. PMID:26077374

  11. The content of Toluene and Xylene in street dust in the vicinity of Kuala Lumpur

    International Nuclear Information System (INIS)

    The objective of this study is to determine the content of toluene and xylene in street dust (<38 ?m and 38 to 63 ?m in diameters) collected at various sites in the vicinity of Kuala Lumpur. Both pollutants were believed had been used as an additive in petrol to increase an octane number. After extraction by either soxhlet or agitating method, gas chromatography with flame ionization detector was used to quantify the amount of both parameters in street dust samples. Result obtained showed that the samples collected in urban areas recorded a higher concentration of toluene and xylene. ANOVA test showed that there are a significant differences between locations due to traffic flows and between two different sizes of dust particles. (author)

  12. Visual evoked potentials in individuals exposed to long-term low concentrations of toluene

    International Nuclear Information System (INIS)

    An investigation of visual evoked potentials was carried out in two groups of subjects; 49 workers employed in a printing-press where toluene has been used exclusively as an organic solvent for the last 30 years, and 59 workers not occupationally exposed to any known neurotoxic substances. The average length of work service in the printing-press was 21.4 years. The level of exposure was assessed by determination of the concentration of toluene in peripheral blood, the concentration of hippuric acid and ortho-cresol in urine in subgroups of subjects chosen at random from both groups. N75, P100 and N145 waves of the pattern reversal visual evoked potentials were analyzed. In the group of exposed subjects, significantly greater amplitudes were found in all waves, with significantly longer latency of the P100 wave. (orig.)

  13. Structural features of HNb3O8 nanosheets and their catalytic performance in toluene nitration

    Science.gov (United States)

    Zhou, Pan; Li, Qingjie; He, Jie; Li, Dewei; Li, Zhong

    2015-11-01

    HNb3O8 nanosheet aggregates ( e-HNb3O8) were prepared by exfoliation and aggregation of layered HNb3O8, which was obtained by protonation of KNb3O8. Especially, in this research, KNb3O8 was synthesized through a novel polymerized complex method (PC) from niobium oxalate. The as-prepared samples were characterized by SEM, HRTEM, XRD, LRS, NH3-TPD, and FT-IR methods. The toluene nitration was used to evaluate the acid catalytic performance of HNb3O8 and e-HNb3O8 samples. The catalytic activity in toluene nitration was related to the structure and acidity of the as-prepared samples. The results show that e-HNb3O8 has a higher specific surface area, stronger acidity and better para-selectivity than the precursor HNb3O8.

  14. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    International Nuclear Information System (INIS)

    The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10-6 g/ml and 10-7 g/ml. Sizes was measured for a period of about 10000 minutes at a constant temperature of 20 deg C. We found that the average size of the particles remained constant with time and increase with an increase in amount of n-heptane. The correlation obtained for size with concentration will be useful in asphaltene precipitation models. (author)

  15. Toluene 4-Monooxygenase and its Complex with Effector Protein T4moD

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Lucas J.; Fox, Brian G. (UW)

    2012-10-16

    Toluene 4-monooxygenase (T4MO) is a multiprotein diiron enzyme complex that catalyzes the regiospecific oxidation of toluene to p-cresol. Catalytic function requires the presence of a small protein, called the effector protein. Effector protein exerts substantial control on the diiron hydroxylase catalytic cycle through protein-protein interactions. High-resolution crystal structures of the stoichometric hydroxylase and effector protein complex described here reveal how protein-protein interactions and reduction of the diiron center produce an active site configuration poised for reaction with O{sub 2}. Further information from crystal structures of mutated isoforms of the hydroxylase and a peroxo adduct is combined with catalytic results to give a fuller picture of the geometry of the enzyme-substrate complex used for the high fidelity oxidation of hydrocarbon substrates.

  16. Hexa-?2-acetato-hexa-n-butylhexa-?3-oxido-tin(IV toluene monosolvate

    Directory of Open Access Journals (Sweden)

    Martin Reichelt

    2013-01-01

    Full Text Available The title compound, [Sn6(C4H96(CH3COO6O6]·C7H8, has one half-toluene molecule and one half-organotin molecule in the asymmetric unit. The latter is situated about an inversion centre and belongs to the class of hexameric monoorganooxotin carboxylates with a hexagonal prismatic or `drum-like' motif of the central tin–oxygen core. Two Sn3O3 rings in a flat-chair conformation are linked via six Sn—O bonds and six bridging acetate groups. All Sn atoms have approximate octahedral coordination geometry. The Sn—O bonds which are trans to the alkyl group are significantly shorter than the others. One butyl group is disordered over two different sites, with occupancies of 0.9:0.1. Very large atomic displacement parameters of the toluene molecule indicate an unresolvable disorder about the twofold axis.

  17. Evaluation of Toluene Exposure in Workers at Industrial Area of Sidoarjo, Indonesia by Measurement of Urinary Hippuric Acid

    Directory of Open Access Journals (Sweden)

    Moch Sahri

    2013-12-01

    How to cite this article: Sahri M, Widajati N. Evaluation of Toluene Exposure in Workers at Industrial Area of Sidoarjo, Indonesia by Measurement of Urinary Hippuric Acid. Asia Pac J Med Toxicol 2013;2:145-9.

  18. Solvothermal-assisted liquid-phase exfoliation of graphite in a mixed solvent of toluene and oleylamine.

    Science.gov (United States)

    Dang, Dinh Khoi; Kim, Eui Jung

    2015-12-01

    We report an effective method for producing graphene sheets using solvothermal-assisted exfoliation of graphite in a mixed solvent of toluene and oleylamine. The mixed solvent of toluene and oleylamine produces higher yield of graphene than its constituents, oleylamine and toluene. The oleylamine molecules with its long chain enwrap the graphene sheets efficiently, while toluene helps the oleylamine molecules become more flexible and easily intercalate into the edge of graphite. The prepared graphene sheets have a high quality, and the concentration of graphene in the dispersion is as high as 0.128 mg mL(-1). The high-quality graphene sheets obtained in this work make them suitable for application in many fields such as energy-storage materials and polymer composites. PMID:26055473

  19. Effect of Substituents on the O-O Bond Rupture of Different Organic Peroxides in Toluene Solution

    OpenAIRE

    A. I. Cañizo; C. M. Mateo; E.E. Alvarez; R. K. Nesprías; G. N. Eyler

    2000-01-01

    The thermal decomposition reaction of cyclic organic peroxides was studied in toluene solution in a wide temperature range. The kinetic data show an important substituent effect on the unimolecular homolysis of the O-O bond of these molecules.

  20. Toluene Effects on Gene Expression in the Hippocampus of Young-Adult, Middle-Age and Senescent Brown Norway Rats

    Science.gov (United States)

    Differential susceptibility to environmental exposure(s) across life stages is an area of toxicology about which little is known. We examined the effects of toluene, a known neurotoxicant with reported behavioral, electrophysiological and pathological effects, on transcriptomic...