WorldWideScience

Sample records for toluene ethyl benzene

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

    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.)

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

    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.)

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

    Directory of Open Access Journals (Sweden)

    K. L. Shivabasappa

    2008-03-01

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

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

    Scientific Electronic Library Online (English)

    K. L., Shivabasappa; P. Nirguna, Babu; Y. Jagannadha, Rao.

    2008-03-01

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

  5. 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.

    2073-20-01

    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.

  6. 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-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC-UNIMOD model.

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

    OpenAIRE

    K. L. Shivabasappa; P. Nirguna Babu; Y. Jagannadha Rao

    2008-01-01

    The present work was carried out in two phases. First, enthalpy of mixing was measured and then the heat of vaporization for the same mixtures was obtained. The data are useful in the design of separation equipments. From the various designs available for the experimental determination of enthalpy of mixing, and heat of vaporization, the apparatus was selected, modified and constructed. The apparatus of enthalpy of mixing was tested with a known system Benzene - i-Butyl Alcohol and the data o...

  8. Radiolysis of cyclic polyether solutions in benzene and toluene

    International Nuclear Information System (INIS)

    Effect of a number of macrocyclic polyethers on dimer product formation during liquid phase benzene and toluene ?-radiolysis (60Co, dose rates 5.0-5.4 Gy/s) is investigated. It is stated that radiation-chemical yield of diphenyl and phenyl cyclohexadienes is considerably decreased during benzene radiolysis in the presence of additions while during toluene radiolysis some increase in dimer yield is observed (excluding dibenzyl in case of dibenzo-24-crown-8 addtion). Possible mechanisms of crown ethers effect on radiolysis of aromatic hydrocarbons are suggested

  9. 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)

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

    International Nuclear Information System (INIS)

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

  11. Gas yields in the radiolysis of benzene, toluene styrene and their mixtures

    International Nuclear Information System (INIS)

    The G-values of H2, CH4 and C2H2 are determined in toluene-benzene and toluene-styrene mixtures. From the results it is concluded that CH3 radicals generated from toluene are captured both by benzene and styrene but, as expected, the reaction is much more efficient with styrene. A radical precursor of C2H2 which could be hexatrienyl is efficiently scavenged by toluene, presumably by H atom transfer. This reaction also accounts for the very low yield of C2H2 in pure toluene. (author)

  12. 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.

  13. Study of thermodesorption of ethyl benzene from zeolite catalysts

    International Nuclear Information System (INIS)

    Thermodesorption of ethyl benzene from different cation and decationized zeolite forms of NaX and NaY types including BeY, NdY, CeY has been investigated by the chromatography method. The thermodesorption spectrum of all the specimens investigated consists of a single peak. Na cation exchange for polyvalent cations results in shifting temperature of thermodesorption type maximum to the low-temperature region. Calculated are diffusion activation energy, pre-exponential factors, effective diffusion coefficients. Dependences of the reaction rate of oxidizing dehydrogenation of ethyl benzene, effective diffusion coefficient on the value of electrostatic cation potential in the Y zeolite go through the NdY maximum

  14. 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 bindites are responsible for the covalent binding to macromolecules which represents a subcellular mechanism by which toluene may express its own in vivo toxicity

  15. Breath and blood levels of benzene, toluene, cumene and styrene in non-occupational exposure.

    Science.gov (United States)

    Brugnone, F; Perbellini, L; Faccini, G B; Pasini, F; Maranelli, G; Romeo, L; Gobbi, M; Zedde, A

    1989-01-01

    Benzene, toluene, cumene and styrene were measured in the breath and blood of two groups of individuals. The first group included individuals belonging to a hospital staff, the second group included chemical workers who were not exposed to the abovementioned chemicals. The chemical workers were examined in plant infirmaries on the morning before the start of the workshift, and the hospital staff in the hospital infirmaries. One environmental air sample was taken in the infirmaries for each individual at the moment of the biological samplings. The environmental concentrations of benzene and styrene were significantly higher in the infirmaries of the chemical plant than in the infirmaries of the hospital. On the other hand, the environmental concentrations of toluene and cumene were not significantly different in the plant infirmaries and in the hospital infirmaries. In the hospital staff the alveolar concentrations of benzene, toluene and styrene were significantly lower than those in the chemical workers. In the hospital staff the blood concentrations of benzene, toluene and styrene were not significantly different from those in the chemical workers. Only the blood cumene concentration was significantly higher in the chemical workers. In hospital staff, smokers showed alveolar and blood concentrations of benzene and toluene that were significantly higher than those measured in the non smoker hospital staff. With reference to chemical workers, only alveolar benzene concentration was significantly higher in smokers than in non smokers.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2707867

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

    International Nuclear Information System (INIS)

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

  17. Secondary organic aerosol formation from m-xylene, toluene, and benzene

    OpenAIRE

    Ng, N. L.; Kroll, J. H; A. W. H. Chan; Chhabra, P. S.; Flagan, R. C.; Seinfeld, J. H.

    2007-01-01

    Secondary organic aerosol (SOA) formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NOx conditions; under high-NOx conditions the peroxy radicals (RO2) react only with NO, while under low-NOx conditions they react only with HO2. For all three aromatics studied (m-xylene, toluene, and benzene), the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass...

  18. Secondary organic aerosol formation from m-xylene, toluene, and benzene

    OpenAIRE

    Seinfeld, J. H.; Flagan, R. C.; Chhabra, P. S.; A. W. H. Chan; Kroll, J. H; Ng, N. L.

    2007-01-01

    Secondary organic aerosol (SOA) formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NOx conditions; under high-NOx conditions the peroxy radicals (RO2) react only with NO, while under low-NOx conditions they react only with HO2. For all three aromatics studied (m-xylene, toluene, and benzene), the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass...

  19. 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.

  20. Cloning and expression of a pathway for benzene and toluene from Bacillus stearothermophilus.

    Science.gov (United States)

    Natarajan, M R; Lu, Z; Oriel, P

    1994-06-01

    Bacillus stearothermophilus strain BR325 demonstrating broad aromatic substrate capability was isolated from petroleum-contaminated soil. The chromosomally-located aromatic pathway from this isolate was cloned into Escherichia coli as a 32 kb insert in cosmid pHC79, conferring growth on benzene, phenol, and toluene as sole carbon sources. PMID:7765116

  1. 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

  2. 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 achievedfor toluene is achieved

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

    International Nuclear Information System (INIS)

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

  4. Electrophilic and free radical nitration of benzene and toluene with various nitrating agents*

    Science.gov (United States)

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

    1978-01-01

    Electrophilic nitration of toluene and benzene was studied under various conditions with several nitrating systems. It was found that high orthopara regioselectivity is prevalent in all reactions and is independent of the reactivity of the nitrating agent. The methyl group of toluene is predominantly ortho-para directing under all reaction conditions. Steric factors are considered to be important but not the sole reason for the variation in the ortho/para ratio. The results reinforce our earlier views that, in electrophilic aromatic nitrations with reactive nitrating agents, substrate and positional selectivities are determined in two separate steps. The first step involves a ?-aromatic-NO2+ ion complex or encounter pair, whereas the subsequent step is of arenium ion nature (separate for the ortho, meta, and para positions). The former determines substrate selectivity, whereas the latter determines regioselectivity. Thermal free radical nitration of benzene and toluene with tetranitromethane in sharp contrast gave nearly statistical product distributions. PMID:16592503

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

    International Nuclear Information System (INIS)

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

  6. Biotransformation of toluene, benzene and naphthalene under anaerobic conditions.

    OpenAIRE

    Langenhoff, A. A. M.

    1997-01-01

    Aromatic hydrocarbons are widespread in nature, due to increasing industrial activity, and often contribute to polluted soils, sediments, and groundwater. Most of these compounds are toxic at relatively high concentrations, but some are already carcinogenic at very low concentrations, e.g. benzene. A growing awareness of the health risks associated with contamination has directed research to the removal or degradation of such compounds. The use of microorganisms to degrade toxic compounds (bi...

  7. Influence of toluene co-exposure on the metabolism and genotoxicity of benzene in mice using continuous and intermittent exposures.

    Science.gov (United States)

    Bird, M G; Wetmore, B A; Letinski, D J; Nicolich, M; Chen, M; Schnatter, A R; Whitman, F T

    2010-03-19

    Benzene exposure in occupational settings often occurs with concurrent exposure to toluene, the methyl-substituted derivative of benzene. Toluene is also readily metabolized by CYP450 isozymes although oxidation primarily occurs in the methyl group. While earlier mouse studies addressing co-exposure to benzene and toluene at high concentrations demonstrated a reduction in benzene-induced genotoxicity, we have previously found, using an intermittent exposure regimen with lower concentrations of benzene (50 ppm) and toluene (100 ppm), that toluene enhances benzene-induced clastogenic or aneugenic bone marrow injury in male CD-1 mice with significantly increased CYP2E1, and depleted GSH and GSSG levels. The follow-up study reported here also used the same daily and total co-exposures but over consecutive days and compared the effects of co-exposure on genotoxicity and metabolism in CD-1 mice both with and without buthionine sulfoximine (BSO) treatment to deplete GSH. In this study the toluene co-exposure doubled the genotoxic response (as determined by the erythrocyte micronucleus test) to benzene alone. Further, GSH depletion caused a reduction in this genotoxicity in both benzene exposed and benzene/toluene co-exposed mice. The results are discussed in terms of the analyses of urinary metabolites from this consecutive day study and the intermittent exposure study as well as levels of CYP2E1, epoxide hydrolase, quinone reductase, alcohol dehydrogenase, and aldehyde dehydrogenase activities. The results suggest that the presence of glutathione is necessary for benzene genotoxicity either as a metabolite conjugate or through an indirect mechanism such as TNF-induced apoptosis. PMID:20079720

  8. Identification of radicals in gamma radiolysis of benzene and toluene by the spin trapping method

    International Nuclear Information System (INIS)

    Using nitrosodurene (ND) and C-phenyl-tertbutylnitrone (PBN) as spin traps in was shown that the ?-irradiation of benzene and toluene resulted in adducts with the phenyl radicals and with the phenyl type and benzyl radicals, respectively. No adducts with the cyclohexadienyl radicals were detected. The ?-irradiation of benzene and toluene in the presence of tertnitrosobutane (TNB) gave the t-Bu2NO radicals, their yield being above 99% with respect to the total yield (G=1.5 radicals/100 eV). The yields of the TNB adducts with radicals from matrix were found to be about 0.01 radicals/100 eV and to be lower then in the presence of ND and PBN

  9. 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

  10. 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)

  11. Hybrid Separation and Detection Device for Analysis of Benzene, Toluene, Ethylbenzene, and Xylenes in Complex Samples

    OpenAIRE

    Iglesias, Rodrigo A.; Tsow, Francis; Wang, Rui; Erica S. Forzani; Tao, Nongjian

    2009-01-01

    We present a hybrid system for rapid detection and analysis of benzene, toluene, ethylbenzene, and xylenes (BTEX). The system combines selective and sensitive sensing elements with a fast and miniaturized chromatographic separation method. The sensing elements are an array of microfabricated quartz crystal tuning forks modified with selective molecularly imprinted polymers, and the separation method uses optimized short columns. The high sensitivity and selectivity of the sensing elements tog...

  12. Degradation of benzene, toluene, ethylbenzene, and xylenes (BTEX) by the lignin-degrading basidiomycete Phanerochaete chrysosporium.

    OpenAIRE

    Yadav, J S; C. A. Reddy

    1993-01-01

    Degradation of the BTEX (benzene, toluene, ethylbenzene, and o-, m-, and p-xylenes) group of organopollutants by the white-rot fungus Phanerochaete chrysosporium was studied. Our results show that the organism efficiently degrades all the BTEX components when these compounds are added either individually or as a composite mixture. Degradation was favored under nonligninolytic culture conditions in malt extract medium, in which extracellular lignin peroxidases (LIPs) and manganese-dependent pe...

  13. Secondary organic aerosol formation from m-xylene, toluene, and benzene

    Directory of Open Access Journals (Sweden)

    J. H. Seinfeld

    2007-03-01

    Full Text Available Secondary organic aerosol (SOA formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NOx conditions; under high-NOx conditions the peroxy radicals (RO2 react only with NO, while under low-NOx conditions they react only with HO2. For all three aromatics studied (m-xylene, toluene, and benzene, the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted under low-NOx conditions substantially exceed those under high-NOx conditions, suggesting the importance of peroxy radical chemistry in SOA formation. Under low-NOx conditions, the SOA yields for m-xylene, toluene, and benzene are constant (36%, 30%, and 37%, respectively, indicating that the SOA formed is essentially nonvolatile. Under high-NOx conditions, aerosol growth occurs essentially immediately, even when NO concentration is high. The SOA yield curves exhibit behavior similar to that observed by Odum et al. (1996, 1997a, b, although the values are somewhat higher than in the earlier study. The yields measured under high-NOx conditions are higher than previous measurements, suggesting a "rate effect" in SOA formation, in which SOA yields are higher when the oxidation rate is faster. Experiments carried out in the presence of acidic seed aerosol reveal no change of SOA yields from the aromatics as compared with those using neutral seed aerosol.

  14. 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)

  15. 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)

  16. 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 fieisplaced 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

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

    Science.gov (United States)

    Feisther, Vódice Amoroz; Ulson de Souza, Antônio Augusto; Trigueros, Daniela Estelita Goes; de Mello, Josiane Maria Muneronde; de Oliveira, Déborade; Guelli Ulson de Souza, Selene M A

    2015-07-01

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

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

    OpenAIRE

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

    2002-01-01

    The soil fungus Cladophialophora sp. strain T1 (= ATCC MYA-2335) was capable of growth on a model water-soluble fraction of gasoline that contained all six BTEX components (benzene, toluene, ethylbenzene, and the xylene isomers). Benzene was not metabolized, but the alkylated benzenes (toluene, ethylbenzene, and xylenes) were degraded by a combination of assimilation and cometabolism. Toluene and ethylbenzene were used as sources of carbon and energy, whereas the xylenes were cometabolized to...

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

    OpenAIRE

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

    2002-01-01

    The soil fungus Cladophialophora sp. strain T1 (= ATCC MYA-2335) was capable of growth on a model water-soluble fraction of gasoline that contained all six BTEX components (benzene, toluene, ethylbenzene, and the xylene isomers). Benzene was not metabolized, but the alkylated benzenes (toluene, ethylbenzene, and xylenes) were degraded by a combination of assimilation and cometabolism. Toluene and ethylbenzene were used as sources of carbon and energy, whereas the xylenes were cometabolized to...

  20. 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).

  1. Secondary organic aerosol formation from m-xylene, toluene, and benzene

    Directory of Open Access Journals (Sweden)

    J. H. Seinfeld

    2007-07-01

    Full Text Available Secondary organic aerosol (SOA formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NOx conditions; under high-NOx conditions the peroxy radicals (RO2 react only with NO, while under low-NOx conditions they react only with HO2. For all three aromatics studied (m-xylene, toluene, and benzene, the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted under low-NOx conditions substantially exceed those under high-NOx conditions, suggesting the importance of peroxy radical chemistry in SOA formation. Under low-NOx conditions, the SOA yields for m-xylene, toluene, and benzene are constant (36%, 30%, and 37%, respectively, indicating that the SOA formed is effectively nonvolatile under the range of Mo(>10 ?g m?3 studied. Under high-NOx conditions, aerosol growth occurs essentially immediately, even when NO concentration is high. The SOA yield curves exhibit behavior similar to that observed by Odum et al. (1996, 1997a, b, although the values are somewhat higher than in the earlier study. The yields measured under high-NOx conditions are higher than previous measurements, suggesting a "rate effect" in SOA formation, in which SOA yields are higher when the oxidation rate is faster. Experiments carried out in the presence of acidic seed aerosol reveal no change of SOA yields from the aromatics as compared with those using neutral seed aerosol.

  2. 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 : ethyl benzene * triethylbenzene * transalkylation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.074, year: 2010

  3. 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.)

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

    Directory of Open Access Journals (Sweden)

    Rosario Rodr\\u00EDguez Arnaiz

    1985-01-01

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

  5. Decomposition of benzene and toluene in air streams in fixed-film photoreactors coated with TiO2 catalyst.

    Science.gov (United States)

    Ku, Young; Chen, Juan-Shiang; Chen, Hua-Wei

    2007-03-01

    The decomposition of benzene and toluene in air streams by UV/TiO2 process was studied in different annular photoreactors under various operating conditions. The shells of reactors used in this research are made of stainless steel, Pyrex glass, or titanium. The TiO2 film was coated to the inner surface of the reactors by either rotating coating or sol-gel techniques. The TiO2 films coated by sol-gel technique were found to be smoother and more uniform than those coated by rotating coating. However, experimental results indicated that the photocatalysis of benzene or toluene in a glass reactor with rotating-coated TiO2 film delivered higher decompositions in air streams than that with sol-gel coated reactors. Benzene and toluene were decomposed more effectively in a coated glass reactor than in a coated stainless steel reactor under the same operating conditions. The presence of water vapor in air-stream plays an important role in the decomposition of benzene and toluene, and a relative humidity of approximately 5-6% was found to be adequate. The presence of excessive amounts of humidity retarded the decomposition to certain extents possibly results from the competitive adsorption of water molecules on the active sites of TiO2. PMID:17385593

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

    International Nuclear Information System (INIS)

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

  7. Studies on cytogenetic effects induced by chronic ?-radiation combined with benzene, toluene and carbon monoxide inhalation in animals

    International Nuclear Information System (INIS)

    8 experimental groups were conducted according to four factors two doses orthogonal layout [L8(27)] in present investigation. 90 healthy male rabbits and 90 healthy male mice were equally divided into 8 experimental groups and control group. Exprimental animals were exposed to ?-radiation combined with benzene, toluene and CO vapour for 2h per day, 5 days per week for 8 weeks. Two doses of ?-radiation, benzene, toluene and CO were 0.0375 and 0.0075 Gy/d (for rabbits, 0.0473 and 0.0095 Gy/d for mice), 182 +- 33 and 40 +- 15 mg/m3, 407 +- 68 and 90 +- 39 mg/m3 as well as 278 +- 18 mg/m3, respectively. The main results were showed as follows: (1) ?-radiation, benzene and toluene could all induce chromosome aberration, SCEs and micronuclei of lymphocytes in rabbits and chromosome aberrations of bone marrow cells in rabbits and mice, but those was no observed in carbon monoxide. (2) ?-radiation and benzene induced chromosome aberrations and micronuclei of lymphocytes in rabbits as well as chromosome aberrations of bone marrow cells in mice, ?-radiation and toluene induced chromosome aberrations of lymphocytes (in rabbits) and bone marrow cells (in mice), benzene and toluene induced chromosome aberrations of lymphocytes (in rabbits) and bone marrow cells (in mice). They showed all significantly interaction. (3) In combined effects, the yield of chromosome aberrations, SCEs and micronuclei induced by (1) experimental groups whinduced by (1) experimental groups which four factors are all high doses were highest, however, those by induced (8) experimental groups which four factors are all low doses also were higher than those of control group and there were statistical difference except SCEs

  8. 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 aloxposed 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.

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

    Directory of Open Access Journals (Sweden)

    H. Heidari

    2009-08-01

    Full Text Available AbstractBackground and Objectives: Analytical methods for volatile organic compounds (VOCs in different samples need extraction of compounds, by applying hazardous solvents. Solid phase micro-extraction (SPME is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are generally present in urine only at trace levels, therefore, a sensitive procedure is needed for their trace determinations. Throughout this study, headspace solid phase micro-extraction (HS-SPME was followed by GC-FID for ethyl benzene in spiked urine was optimized.Methods: In this study, the parameters influencing SPME and gas chromatography of ethyl benzene, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were investigated. Results: Extraction procedure was performed at 30°C for 6 min, using 0.2 gml-1 of NaCl in the sample solution. The sample volume and sample pH were optimized at 5 ml and 7 (neutral pH, respectively. Desorption of the ethyl benzene was carried out for 60 sec. at 250°C. The method was also validated with three different spiked urine samples and illustrated an appropriate reproducibility over six consecutive days as well as six within-day experiments. During this investigation, parameters of accuracy, linearity, and detection limits of the procedure were also evaluated.Conclusion: The developed method of HS- SPME-GC-FID proved to be a simple, convenient, and practical procedure, and was successfully used for measuring of ethyl benzene in spiked urine.

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

    International Nuclear Information System (INIS)

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

  11. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-15

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

  13. 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.

  14. Efficient removal of toluene and benzene in gas phase by the TiO2/Y-zeolite hybrid photocatalyst.

    Science.gov (United States)

    Takeuchi, Masato; Hidaka, Manabu; Anpo, Masakazu

    2012-10-30

    Efficient removal of toluene or benzene molecules thinly diffused in gas phase was achieved by using TiO(2)/Y-zeolite hybrid photocatalysts. TiO(2) of 10 wt% hybridized with a hydrophobic USY zeolite showed higher photocatalytic reactivity as compared to TiO(2) hybridized with hydrophilic H-Y or Na-Y zeolites. This phenomenon can be explained by the fact that the hydrophobic USY zeolite efficiently adsorbs the organic compounds and smoothly supplies them onto the TiO(2) photocatalyst surface. However, the toluene or benzene molecules, which are strongly trapped on the hydrophilic H(+) or Na(+) sites of zeolite, cannot diffuse onto the TiO(2) surfaces, resulting in lower photocatalytic reactivity. Although the adsorption capacity of the pure TiO(2) sample rapidly deteriorated, the TiO(2)/Y-zeolite hybrid system maintained a high adsorption efficiency to remove such aromatic compounds for a long period. PMID:22947182

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

    OpenAIRE

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

    2005-01-01

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

  16. 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 mixtureindustry when it is considered the mixture of the three solvents

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

    Directory of Open Access Journals (Sweden)

    H Heidari

    2012-05-01

    Full Text Available

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

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

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

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

  18. Conversion of ethyl benzene on alumina supported Co(Ni)Mo(W) catalysts

    International Nuclear Information System (INIS)

    The alumina supported cobalt-molybdenum, nickel-molybdenum and nickel-tungsten catalysts were prepared by coprecipitation method and activated to obtain oxidized, reduced and sulphide forms. The surface area, pore volume, main pore diameter, surface acidity were measured. The activity in dehydrogenation of ethyl benzene (EB) has been studied at 460 C in continuous flow micro reactor. It was suggested that coordinatively unsaturated ions: Al3+ and Me6+, Me5+ (Me=Mo or W) as Lewis acid sites and oxygen ions and/or sulphur ions basic sites were the main active centres for dehydrogenation. (author). 22 refs, 1 fig., 3 tabs

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

    Science.gov (United States)

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

    2015-05-01

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

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

    International Nuclear Information System (INIS)

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

  1. 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.

  2. 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)

  3. 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)

  4. Evaluation of an FIA Operated Amperometric Bacterial Biosensor, Based on Pseudomonas Putida F1 for the Detection of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX)

    OpenAIRE

    Rasinger, Josef D.; Marrazza, Giovanna; Briganti, Fabrizio; Scozzafava, Andrea; Mascini, Marco; Turner, Anthony P. F.

    2005-01-01

    Recently, the development and optimization of a flow injection analysis (FIA) operated bacterial biosensor based on the aerobic catabolism of Pseudomonas putida ML2 was reported in the literature (Lanyon et al. 2004, 2005). By adapting information from these reports, we investigated whether operating parameters and procedures of the benzene biosensor could be directly applied to a new system based on a different bacterial strain for the detection of the whole benzene, toluene, ethylbenzene, a...

  5. Assessment of genotoxicity of methyl-tert-butyl ether, benzene, toluene, ethylbenzene, and xylene to human lymphocytes using comet assay

    International Nuclear Information System (INIS)

    Methyl-tert-butyl ether (MTBE) is a gasoline oxygenate and antiknock additive substituting for lead alkyls currently in use worldwide. Benzene, toluene, ethylbenzene, and xylene (BTEX) are volatile monoaromatic hydrocarbons which are commonly found together in crude petroleum and petroleum products such as gasoline. The aim of this study is to evaluate the genotoxic effects of these tested chemicals in human lymphocytes. Using the alkaline comet assay, we showed that all of the tested chemicals induce DNA damage in isolated human lymphocytes. This effect could follow from the induction of DNA strands breaks. The neutral version of the test revealed that MTBE, benzene, and xylenes induce DNA double-strand breaks at 200 ?M. Apart from MTBE, the spin traps, 5,5-dimethyl-pyrroline-N-oxide (DMPO) and N-tert-butyl-?-phenylnitrone (PBN) can decrease the level of DNA damage in BTEX at 200 ?M. This indicated that DNA damage could result from the participation of free radicals in DNA-damaging effect, which was further supported by the fact that post-treatment of formamidopyrimidine-DNA glycosylase (Fpg), enzyme recognizing oxidized DNA purines, gave rise to a significant increase in the extent of DNA damage in cells treated with benzene, and xylene at 200 ?M. The results obtained suggested that MTBE and BTEX could induce a variety type of DNA damage such as single-strand breaks (SSBs), double-strand breaks (DSBs), and oxidative base modificationification

  6. 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.

  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. Dynamics of an Oligotrophic Bacterial Aquifer Community during Contact with a Groundwater Plume Contaminated with Benzene, Toluene, Ethylbenzene, and Xylenes: an In Situ Mesocosm Study.

    Czech Academy of Sciences Publication Activity Database

    Hendrickx, B.; Dejonghe, W.; Boenne, W.; Brennerová, Mária; ?erník, M.; Lederer, T.; Bucheli-Vitschel, M.; Bastiaens, L.; Verstraete, W.; Top, E.M.; Diels, L.; Springael, D.

    2005-01-01

    Ro?. 71, ?. 7 (2005), s. 3815-3825. ISSN 0099-2240 Grant ostatní: European Commission(XE) QLK3-CT2000-0031 Institutional research plan: CEZ:AV0Z50200510 Keywords : oligotrophic bacterial * benzene * toluene Subject RIV: EE - Microbiology, Virology Impact factor: 3.818, year: 2005

  9. 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

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

    International Nuclear Information System (INIS)

    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

  11. 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

  12. 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

  13. 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.

  14. Benzene

    Science.gov (United States)

    Benzene is a colorless or light-yellow liquid chemical at room temperature. It is used primarily as a solvent in the chemical and pharmaceutical industries, as a starting material and an intermediate in the synthesis of numerous chemicals, and in gasoline. Benzene is produced by both natural and man-made processes. It is a natural component of crude oil, which is the main source of benzene produced today. Other natural sources include gas emissions from volcanoes and forest fires.

  15. 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.

  16. 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.

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

    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)

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

    OpenAIRE

    Dueholm, Morten S.; Albertsen, Mads; D’Imperio, Seth; Tale, Vaibhav P.; Lewis, Derrick; Nielsen, Per Halkjær; Nielsen, Jeppe Lund

    2014-01-01

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

  19. The effect of the potential fuel additive isobutanol on benzene, toluene, ethylbenzene, and p-xylene degradation in aerobic soil microcosms.

    Science.gov (United States)

    Ding, Liang; Cupples, Alison M

    2015-01-01

    Isobutanol is being considered as a fuel additive; however, the effect of this chemical on gasoline degradation (following a spill) has yet to be fully explored. To address this, the current study investigated the effect of isobutanol on benzene, toluene, ethylbenzene and p-xylene (BTEX) degradation in 14 sets of experiments in saturated soils. This involved four hydrocarbons for three soils (12 experiments) and two extra experiments with a lower level of isobutanol (for toluene only). Each soil and hydrocarbon combination involved four abiotic control microcosms and 12 sample microcosms (six with and six without isobutanol). The time for complete degradation of each hydrocarbon varied between treatments. Both toluene and ethylbenzene were rapidly degraded (5-13 days for toluene and 3-13 days for ethylbenzene). In contrast, the time for complete degradation for benzene ranged from 5 to 47 days. The hydrocarbon p-xylene was the most recalcitrant chemical (time for removal ranged from 14 to 86 days) and, in several microcosms, no p-xylene degradation was observed. The effect of isobutanol on hydrocarbon degradation was determined by comparing degradation lag times with and without isobutanol addition. From the 14 treatments, isobutanol only affected degradation lag times in three cases. In two cases (benzene and p-xylene), an enhancement of degradation (reduced lag times) was observed in the presence of isobutanol. In contrast, toluene degradation in one soil was inhibited (increased lag time). These results indicate that co-contamination with isobutanol should not inhibit aerobic BTEX degradation rates. PMID:25413118

  20. 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: 0.76-0.8 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

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    Adrián H. Buep

    2014-12-01

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

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

    Science.gov (United States)

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

    2009-11-27

    A new procedure for the passive sampling in air of benzene, toluene, ethylbenzene and xylene isomers (BTEX) is proposed. A low-density polyethylene layflat tube filled with a mixture of solid phases provided a high versatility tool for the sampling of volatile compounds from air. Several solid phases were assayed in order to increase the BTEX absorption in the sampler and a mixture of florisil and activated carbon provided the best results. Direct head-space-gas chromatography-mass spectrometry (HS-GC-MS) measurement of the whole deployed sampler was employed for a fast determination of BTEX. Absorption isotherms were used to develop simple mathematical models for the estimation of BTEX time-weighted average concentrations in air. The proposed samplers were used to determine BTEX in indoor air environments and results were compared with those found using two reference methodologies: triolein-containing semipermeable membrane devices (SPMDs) and diffusive Radiello samplers. In short, the developed sampling system and analytical strategy provides a versatile, easy and rapid atmospheric monitor (VERAM). PMID:19853854

  4. Biodegradation Kinetics of Tetrahydrofuran, Benzene, Toluene, and Ethylbenzene as Multi-substrate by Pseudomonas oleovorans DT4

    Directory of Open Access Journals (Sweden)

    Dong-Zhi Chen

    2014-12-01

    Full Text Available The biodegradation kinetics of tetrahydrofuran, benzene (B, toluene (T, and ethylbenzene (E were systematically investigated individually and as mixtures by a series of aerobic batch degradation experiments initiated by Pseudomonas oleovorans DT4. The Andrews model parameters, e.g., maximum specific growth rates (?max, half saturation, and substrate inhibition constant, were obtained from single-substrate experiments. The interaction parameters in the sum kinetics model (SKIP were obtained from the dual substrates. The ?max value of 1.01 for tetrahydrofuran indicated that cell growth using tetrahydrofuran as carbon source was faster than the growth on B (?max, B = 0.39 or T (?max, T = 0.39. The interactions in the dual-substrate experiments, including genhancement, inhibition, and co-metabolism, in the mixtures of tetrahydrofuran with B or T or E were identified. The degradation of the four compounds existing simultaneously could be predicted by the combination of SKIP and co-metabolism models. This study is the first to quantify the interactions between tetrahydrofuran and BTE.

  5. Biodegradation kinetics of tetrahydrofuran, benzene, toluene, and ethylbenzene as multi-substrate by Pseudomonas oleovorans DT4.

    Science.gov (United States)

    Chen, Dong-Zhi; Ding, Yun-Feng; Zhou, Yu-Yang; Ye, Jie-Xu; Chen, Jian-Meng

    2015-01-01

    The biodegradation kinetics of tetrahydrofuran, benzene (B), toluene (T), and ethylbenzene (E) were systematically investigated individually and as mixtures by a series of aerobic batch degradation experiments initiated by Pseudomonas oleovorans DT4. The Andrews model parameters, e.g., maximum specific growth rates (?max), half saturation, and substrate inhibition constant, were obtained from single-substrate experiments. The interaction parameters in the sum kinetics model (SKIP) were obtained from the dual substrates. The ?max value of 1.01 for tetrahydrofuran indicated that cell growth using tetrahydrofuran as carbon source was faster than the growth on B (?max, B = 0.39) or T (?max, T = 0.39). The interactions in the dual-substrate experiments, including genhancement, inhibition, and co-metabolism, in the mixtures of tetrahydrofuran with B or T or E were identified. The degradation of the four compounds existing simultaneously could be predicted by the combination of SKIP and co-metabolism models. This study is the first to quantify the interactions between tetrahydrofuran and BTE. PMID:25561017

  6. 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.

  7. Biomass fuels and coke plants are important sources of human exposure to polycyclic aromatic hydrocarbons, benzene and toluene.

    Science.gov (United States)

    Fan, Ruifang; Li, Junnan; Chen, Laiguo; Xu, Zhencheng; He, Dechun; Zhou, Yuanxiu; Zhu, Yuanyuan; Wei, Fusheng; Li, Jihua

    2014-11-01

    Large amounts of carcinogenic polycyclic aromatic hydrocarbons (PAHs), benzene and toluene (BT) might be emitted from incomplete combustion reactions in both coal tar factories and biomass fuels in rural China. The health effects arising from exposure to PAHs and BT are a concern for residents of rural areas close to coal tar plants. To assess the environmental risk and major exposure sources, 100 coke plant workers and 25 farmers in Qujing, China were recruited. The levels of 10 mono-hydroxylated PAHs (OH-PAHs), four BT metabolites and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine collected from the subjects were measured. The 8-OHdG levels in the urine were determined to evaluate the oxidative DNA damage induced by the PAHs and BT. The results showed that the levels of the OH-PAHs, particularly those of 1-hydroxynathalene and 1-hydroxypyrene, in the farmers were 1-7 times higher than those in the workers. The concentrations of the BT metabolites were comparable between the workers and farmers. Although the exact work location within a coke oven plant might affect the levels of the OH-PAHs, one-way ANOVA revealed no significant differences for either the OH-PAHs levels or the BT concentrations among the three groups working at different work sites. The geometric mean concentration (9.17 µg/g creatinine) of 8-OHdG was significantly higher in the farmers than in the plant workers (6.27 µg/g creatinine). The levels of 8-OHdG did not correlate with the total concentrations of OH-PAHs and the total levels of BT metabolites. Incompletely combusted biomass fuels might be the major exposure source, contributing more PAHs and BT to the local residents of Qujing. The estimated daily intakes (EDIs) of naphthalene and fluorene for all of the workers and most of the farmers were below the reference doses (RfDs) recommended by the U.S. Environmental Protection Agency (EPA), except for the pyrene levels in two farmers. However, the EDIs of benzene in the workers and local farmers ranged from 590 to 7239 µg/day, and these levels were 2- to 30-fold higher than the RfDs recommended by the EPA. Biomass fuel combustion and industrial activities related to coal tar were the major sources of the PAH and BT exposure in the local residents. Using biomass fuels for household cooking and heating explains the higher exposure levels observed in the farmers relative to the workers at the nearby coal tar-related industrial facility. PMID:25261857

  8. Macroscopic chirality of supramolecular gels formed from achiral tris(ethyl cinnamate) benzene-1,3,5-tricarboxamides.

    Science.gov (United States)

    Shen, Zhaocun; Wang, Tianyu; Liu, Minghua

    2014-12-01

    A C3 -symmetric benzene-1,3,5-tricarboxamide substituted with ethyl cinnamate was found to self-assemble into supramolecular gels with macroscopic chirality in a DMF/H2 O mixture. The achiral compound simultaneously formed left- and right-handed twists in an unequal number, thus resulting in the macroscopic chirality of the gels without any chiral additives. Furthermore, ester-amide exchange reactions with chiral amines enabled the control of both the handedness of the twists and the macroscopic chirality of the gels, depending on the structures of the chiral amines. These results provide new prospects for understanding and regulating symmetry breaking in assemblies of supramolecular gels formed from achiral molecular building blocks. PMID:25283772

  9. 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

  10. Comparative Genomic Analysis and Benzene, Toluene, Ethylbenzene, and o-, m-, and p-Xylene (BTEX) Degradation Pathways of Pseudoxanthomonas spadix BD-a59

    OpenAIRE

    Choi, Eun Jin; Jin, Hyun Mi; Lee, Seung Hyeon; Math, Renukaradhya K.; Madsen, Eugene L.; Jeon, Che Ok

    2013-01-01

    Pseudoxanthomonas spadix BD-a59, isolated from gasoline-contaminated soil, has the ability to degrade all six BTEX (benzene, toluene, ethylbenzene, and o-, m-, and p-xylene) compounds. The genomic features of strain BD-a59 were analyzed bioinformatically and compared with those of another fully sequenced Pseudoxanthomonas strain, P. suwonensis 11-1, which was isolated from cotton waste compost. The genome of strain BD-a59 differed from that of strain 11-1 in many characteristics, including th...

  11. Excess molar volumes of (propiophenone+benzene, or toluene, or ethylbenzene, or butylbenzene) at temperatures 298.15K and 328.15K

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Ye, Connie Z; Ariya, Parisa A

    2015-05-01

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

  13. Quantitative evaluation of benzene, toluene, and xylene in the larvae of Drosophila melanogaster by solid-phase microextraction/gas chromatography/mass spectrometry for potential use in toxicological studies.

    Science.gov (United States)

    Mudiam, Mohana Krishna Reddy; Singh, Mahendra Pratap; Chowdhuri, Debapratim Kar; Murthy, Ramesh Chandra

    2010-01-01

    A simple, rapid, and solvent-free method for quantitative determination of benzene, toluene, and Xylene in exposed Drosophila larvae was developed using headspace solid-phase microextraction (HS-SPME) coupled to GC/MS. Larvae fed on standard Drosophila food mixed with benzene, toluene, and Xylene for 48 h were homogenized in Milli-Q water. Extraction of benzene, toluene, and Xylene was performed at 65 degrees C for 30 min on the SPME fiber (silica-fused). Subsequently, the fiber was desorbed in the GC injection port, followed by GC/MS analysis in the selected-ion monitoring mode. An external calibration curve was used for the quantification of benzene, toluene, and Xylene in the exposed organism. Recoveries were in the range of 78-82% (intraday) and 76-81% (interday) in larvae, and 91-96% (intraday) and 87-92% (interday) in the diet. LOD with an S/N of 3:1 and LOQ with an S/N of 10:1 were in the range of 0.01-0.023 and 0.034-0.077 microg/L, respectively. Percent RSD values for benzene, toluene, and Xylene were in the range of 0.50-0.81 (intraday) and 0.89-1.23 (interday) for retention time, and 2.16--3.85 (intraday) and 2.99-4.95 (interday) for peak concentration, showing good repeatability. This method was sensitive enough to quantitate benzene, toluene, and Xylene in small exposed organisms like Drosophila larvae. The SPME/GC/MS method developed may have wider applications in various in vivo toxicological studies. PMID:21140672

  14. 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.

  15. Induction of hsp70, hsp60, hsp83 and hsp26 and oxidative stress markers in benzene, toluene and xylene exposed Drosophila melanogaster: Role of ROS generation

    International Nuclear Information System (INIS)

    Exposure to benzene, toluene and xylene in the human population may pose a health risk. We tested a working hypothesis that these test chemicals cause cellular toxicity to a non-target organism, Drosophila melanogaster. Third instar larvae of D. melanogaster transgenic for hsp70, hsp83 and hsp26 and Oregon R+ strain were exposed to 1.0-100.0 mM benzene, toluene and xylene for 2-48 h to examine the heat shock proteins (hsps), ROS generation, anti-oxidant stress markers and developmental end points. The test chemicals elicited a concentration- and time-dependent significant (p hsp83 ? hsp26 as evident by ?-galactosidase activity after 24 h. RT-PCR amplification studies in Oregon R+ larvae revealed a similar induction pattern of these genes along with hsp60 in the order of hsp70 > hsp60 > hsp26 ? hsp83. Under similar experimental conditions, a significant induction of ROS generation and oxidative stress markers viz. superoxide dismutase, catalase, glutathione S-transferase, thioredoxin reductase, glutathione, malondialdehyde and protein carbonyl content was observed. Sub-organismal response was propagated towards organismal response i.e., a delay in the emergence of flies and their reproductive performance. While hsp70 was predominantly induced in the organism till 24 h of treatment with the test chemicals, a significant or insignificant regression of Hsp70 after 48 hficant regression of Hsp70 after 48 h was concurrent with a significant induction (p hsp83 ? hsp26 in comparison to the former. A significant positive correlation was observed between ROS generation and these hsps in the exposed organism till 24 h and a negative correlation between ROS generation and hsp70 in them after 48 h indicating a modulatory role of ROS in the induction of hsps. The study suggests that among the tested hsps, hsp70 may be used as an early bioindicator of cellular toxicity against benzene, toluene and xylene and D. melanogaster as an alternative animal model for screening the risk posed by environmental chemicals

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

    International Nuclear Information System (INIS)

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

  17. Substoichiometric isotope dilution analysis of arsenic in biological and environmental standard reference materials by solvent extraction using toluene-3,4-dithiol in benzene

    International Nuclear Information System (INIS)

    A radiochemical solvent extraction procedure has been developed for the determination of As(III) using 76As tracer. It is based on the complexation of As(III) with toluene-3,4-dithiol (TDT) at pH 2 and subsequent extraction in benzene. The effect of various parameters such as pH, time of equilibration, nature of solvent, quantitative character and interferences have been studied. The method has been further developed into substoichiometric isotope dilution analysis for the determination of As at < 1?g level and employed for the analysis of several environmental and biological standard Reference Materials from NIST (USA), IAEA (Vienna) and NIES (Japan). (author) 39 refs.; 4 figs.; 4 tabs

  18. Consecutive reactions of aromatic OH adducts with NO, NO2 and O2: benzene, toluene, m- and p-xylene, hexamethylbenzene, phenol, m-cresol and aniline

    Science.gov (United States)

    Koch, R.; Knispel, R.; Elend, M.; Siese, M.; Zetzsch, C.

    2006-08-01

    Consecutive reactions of adducts, resulting from OH radicals and aromatics, with the tropospheric scavenger molecules O2, NO and NO2 have been studied for benzene, toluene, m- and p-xylene, hexamethylbenzene, phenol, m-cresol and aniline by observing decays of OH at temperatures where the thermal back-decomposition to OH is faster than 3 s-1, typically between 300 and 340 K. The experimental technique was resonance fluorescence with flash photolysis of water as source of OH. Biexponential decays were observed in the presence of either O2 or NO, and triexponential decays were obtained in the presence of NO2. The kinetic analysis was performed by fitting the relevant rate constants of the reaction mechanism to whole sets of decays obtained at various concentrations of aromatic and scavenger. In the case of hexamethylbenzene, the biexponential decays suggest the existence of the ipso-adduct, and the slightly higher necessary temperatures show that it is even more stable. In addition, smog chamber experiments at O2 concentrations from atmospheric composition down to well below 100 ppm have been carried out for benzene, toluene and p-xylene. The drop of the effective rate constant of removal by OH occurs at reasonable O2 levels, given the FP/RF results. Comparison of the adduct reactivities shows for all aromatics of this study that the reaction with O2 predominates over that with NO2 under all tropospheric conditions, and that a reaction with NO may only occur after the reaction with O2.

  19. The effect of water presence on the photocatalytic oxidation of benzene, toluene, ethylbenzene and m-xylene in the gas-phase

    Science.gov (United States)

    Korologos, Christos A.; Philippopoulos, Constantine J.; Poulopoulos, Stavros G.

    2011-12-01

    In the present work, the gas-solid heterogeneous photocatalytic oxidation of benzene, toluene, ethylbenzene and m-xylene (BTEX) over UV-irradiated titanium dioxide was studied in an annular reactor operated in the CSTR (continuous stirred-tank reactor) mode. GC-FID and GC-MS were used for analysing reactor inlet and outlet streams. Initial BTEX concentrations were in the low parts per million (ppmv) range, whereas the water concentration was in the range of 0-35,230 ppmv and the residence time varied from 50 to 210 s. The effect of water addition on the photocatalytic process showed strong dependence on the type of the BTEX and the water vapour concentration. The increase in residence time resulted in a considerable increase in the conversion achieved for all compounds and experimental conditions. There was a clear interaction between residence time and water presence regarding the effect on conversions achieved. It was established that conversions over 95% could be achieved by adjusting appropriately the experimental conditions and especially the water concentration in the reactor. In all cases, no by-products were detected above the detection limit and carbon dioxide was the only compound detected. Finally, various Langmuir-Hinshelwood kinetic models have been tested in the analysis of the experimental data obtained. The kinetic data obtained confirmed that water had an active participation in the photocatalytic reactions of benzene, toluene, ethylbenzene and m-xylene since the model involving reaction of BTEX and water adsorbed on different active sites yielded the most successful fitting to the experimental results for the first three compounds, whereas the kinetic model based on the assumption that reaction between VOC and water dissociatively adsorbed on the photocatalyst takes place was the most appropriate in the case of m-xylene.

  20. Degradation of benzene, toluene, and xylene isomers by a bacterial consortium obtained from rhizosphere soil of Cyperus sp. grown in a petroleum-contaminated area.

    Science.gov (United States)

    Ortega-González, Diana Katherine; Zaragoza, Diego; Aguirre-Garrido, José; Ramírez-Saad, Hugo; Hernández-Rodríguez, César; Jan-Roblero, Janet

    2013-11-01

    Increasing contamination of soil and groundwater with benzene, toluene, and xylene (BTX) due to activities of the chemical and oil refinery industry has caused serious environmental damage. Efficient methods are required to isolate and degrade them. Microorganisms associated with rhizosphere soil are considered efficient agents to remediate hydrocarbon contamination. In this study, we obtained a stabilized bacterial consortium from the rhizosphere soil of Cyperus sp. grown in a petroleum-contaminated field in Southern Mexico. This consortium was able to completely degrade BTX in 14 days. Bacteria isolated from the consortium were identified by 16S rRNA gene sequence analysis as Ralstonia insidiosa, Cellulomonas hominis, Burkholderia kururiensis, and Serratia marcescens. The BTX-degradation capacity of the bacterial consortium was confirmed by the detection of genes pheA, todC1, and xylM, which encoded phenol hydroxylase, toluene 1,2-dioxygenase, and xylene monooxygenase, respectively. Our results demonstrate feasibility of BTX biodegradation by indigenous bacteria that might be used for soil remediation in Southern Mexico. PMID:23564628

  1. Isotope effects in aqueous systems. 13. The hydrophobic interaction. Some thermodynamic properties of benzene/water and toluene/water solutions and their isotope effects

    International Nuclear Information System (INIS)

    Henry's law constants, K/sub H/ = K0 + K1X, have been measured as a function of concentration for the water-rich and benzene-rich solutions C6H6/H2O and C6H6/D2O and for the water-rich solutions C6D6/H2O and C6D6/D2O at several temperatures The constants K0 and K1 are sensitive to temperature and to isotopic label. The vapor pressure results have been supplemented with measurements of the apparent molar volumes of the solutions listed above, as well as for H2O- and D2O-rich solutions of toluene and deuteriotoluene, and with determinations of the solubilities and solubility isotope effects of the toluene solutions. The data have been interpreted in the context of the theory of isotope effects in condensed-phase systems. That analysis indicates that a significant dynamical vibrational coupling between solute and solvent normal modes occurs in these solutions. The result is of interest particularly as it pertains to models of the hydrophobic interaction

  2. Application to ethyl-benzene of a numerical method allowing improvement of NMR spectra resolution and determination of individual component parameters

    International Nuclear Information System (INIS)

    A method for estimating parameters of exponentially damped sinusoidal transients has been applied to a NMR spectrum of ethyl-benzene. As it uses the peak derivatives rather than the classical Fourier ones, it makes them thinner and therefore allows an important resolution improvement. When such separated peaks are pure lorentzian ones, it is possible to estimate their five characteristic parameters, i.e. frequency, amplitude, damping factor, initial phase and time-delay. Gaussian peaks may be treated in the same way. (authors). 3 refs., 6 figs

  3. Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.

    Science.gov (United States)

    Valcke, Mathieu; Haddad, Sami

    2015-01-01

    The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered. PMID:25785556

  4. 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...

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

    International Nuclear Information System (INIS)

    Highlights: • Co3O4 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 Co3O4 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

  6. 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.

  7. 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)

  8. Gas-phase reaction of daughter ions from the decay of multitritiated propane with benzene and toluene. Solution of a longstanding anomaly

    International Nuclear Information System (INIS)

    The population of the daughter ions from the decay of multitritiated propane has been sampled by using as a probe their gas-phase reactions with benzene and toluene at pressures up to 400 torr. Tritiated n- and isopropylated arenes account together for 70 to 75% of the total activity of the decay ions. This observation - and the failure to detect aromatic allylation - removes an early radiochemical anomaly, by showing that decay of tritiated propane yields propyl ions as the most abundant daughter species, following a trend established for all other tritiated hydrocarbons. The abnormally high abundance of allyl ions measured by mass spectrometry is traced to the decomposition C3H7+ ? C3H5 + H2 allowed by its low activation energy, the lack of collisional stabilization, and the long residence time which characterizes operation of a charge mass spectrometer. The excitation energy required for the decomposition is likely to arise from the deformation energy of the propyl cations, born from the sudden nuclear transition in a shape reminiscent of the parent hydrocarbon molecule

  9. (1RS,6SR-Ethyl 4-(4-chlorophenyl-6-(4-fluorophenyl-2-oxocyclohex-3-ene-1-carboxylate toluene hemisolvate

    Directory of Open Access Journals (Sweden)

    Grzegorz Dutkiewicz

    2011-02-01

    Full Text Available In the crystal structure of the title compound, C21H18ClFO3·0.5C7H8, the toluene solvent molecules occupy special positions on centres of symmetry, and consequently are disordered across this site. The cyclohexene ring has a slightly distorted sofa conformation; the two benzene rings are inclined by 72.90?(7° and their planes make dihedral angles of 30.09?(10 (chlorophenyl and 88.13?(6° (fluorophenyl with the approximately planar part of the cyclohexenone ring [maximum deviation from plane through five atoms is 0.030?(2?Å, the sixth atom is 0.672?(3Å out of this plane]. Weak intermolecular C—H...O and C—H...X (X = F, Cl interactions join molecules into a three-dimensional structure. Also, a relatively short and directional C—Cl...F—C contact is observed [Cl...F = 3.119?(2?Å, C—Cl...F = 157.5?(2° and C—F...Cl 108.3?(2°]. The solvent molecules fill the voids in the crystal structure and are kept there by relatively short and directional C—H...? interactions.

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

    Science.gov (United States)

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

    2015-05-11

    A new and simple method for benzene, toluene, ethylbenzene and o-xylene (BTEX) quantification in vehicle exhaust was developed based on diffusion-controlled extraction onto a retracted solid-phase microextraction (SPME) fiber coating. The rationale was to develop a method based on existing and proven SPME technology that is feasible for field adaptation in developing countries. Passive sampling with SPME fiber retracted into the needle extracted nearly two orders of magnitude less mass (n) compared with exposed fiber (outside of needle) and sampling was in a time weighted-averaging (TWA) mode. Both the sampling time (t) and fiber retraction depth (Z) were adjusted to quantify a wider range of Cgas. Extraction and quantification is conducted in a non-equilibrium mode. Effects of Cgas, t, Z and T were tested. In addition, contribution of n extracted by metallic surfaces of needle assembly without SPME coating was studied. Effects of sample storage time on n loss was studied. Retracted TWA-SPME extractions followed the theoretical model. Extracted n of BTEX was proportional to Cgas, t, Dg, T and inversely proportional to Z. Method detection limits were 1.8, 2.7, 2.1 and 5.2mgm(-3) (0.51, 0.83, 0.66 and 1.62ppm) for BTEX, respectively. The contribution of extraction onto metallic surfaces was reproducible and influenced by Cgas and t and less so by T and by the Z. The new method was applied to measure BTEX in the exhaust gas of a Ford Crown Victoria 1995 and compared with a whole gas and direct injection method. PMID:25911428

  11. Co-exposure to polycyclic aromatic hydrocarbons, benzene and toluene and their dose-effects on oxidative stress damage in kindergarten-aged children in Guangzhou, China.

    Science.gov (United States)

    Li, Junnan; Lu, Shaoyou; Liu, Guihua; Zhou, Yuanxiu; Lv, Yanshan; She, Jianwen; Fan, Ruifang

    2015-08-15

    Polycyclic aromatic hydrocarbons (PAHs), benzene and toluene (BT) are ubiquitous toxic pollutants in the environment. Children are sensitive and susceptible to exposure to these contaminants. To investigate the potential oxidative DNA damage from the co-exposure of PAHs and BT in children, 87 children (aged 3-6) from a kindergarten in Guangzhou, China, were recruited. Ten urinary PAHs and four BT metabolites, as well as 8-hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of oxidative DNA damage)in urine, were determined using a liquid chromatography tandem mass spectrometer. The results demonstrated that the levels of PAHs and BT in children from Guangzhou were 2-30 times higher than those in children from the other countries based on a comparison with recent data from the literature. In particular, the difference is more substantial for pyrene and volatile BT. Co-exposure to PAHs and BT could lead to additive oxidative DNA damage. Significant dose-effects were observed between the sum concentration of urinary monohydroxylated metabolites of PAHs (?OH-PAHs), the sum concentration of the metabolites of BT (?BT) and 8-OHdG levels. Every one percent increase in urinary PAHs and BT generated 0.33% and 0.02% increases in urinary 8-OHdG, respectively. We also determined that the urinary levels of PAHs and BT were negatively associated with the age of the children. Moreover, significant differences in the levels of ?OH-PAHs and ?BT were determined between 3- and 6-year-old children (pburden of PAH and BT exposure compared with older children. PMID:25889546

  12. 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%.

  13. 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.

  14. 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].

  15. 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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  18. 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.

  19. 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

  20. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Bruno R.S. de; Zampieri, Davila S.; Rodrigues, Jose Augusto R.; Moran, Paulo J.S., E-mail: moran@iqm.unicamp.br [Institute of Chemistry, University of Campinas, Campinas-SP (Brazil); Zukerman-Schpector, Julio [Department of Chemistry, Federal University of Sao Carlos, SP (Brazil); Tiekink, Edward R.T. [Department of Chemistry, University of Malaya, Kuala Lampur (Malaysia)

    2012-05-15

    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 deg C). These conditions represent a greener 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 {sup 13}C NMR (nuclear magnetic resonance) is presented. (author)

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

    International Nuclear Information System (INIS)

    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 deg C). These conditions represent a greener 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. (author)

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Xin-Ping Kang

    2010-11-01

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

  5. 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)

  6. Monohydroxylation of Phenol and 2,5-Dichlorophenol by Toluene Dioxygenase in Pseudomonas putida F1

    OpenAIRE

    1991-01-01

    Pseudomonas putida F1 contains a multicomponent enzyme system, toluene dioxygenase, that converts toluene and a variety of substituted benzenes to cis-dihydrodiols by the addition of one molecule of molecular oxygen. Toluene-grown cells of P. putida F1 also catalyze the monohydroxylation of phenols to the corresponding catechols by an unknown mechanism. Respirometric studies with washed cells revealed similar enzyme induction patterns in cells grown on toluene or phenol. Induction of toluene ...

  7. Direct hydroxylation of benzene to phenol using hydrogen peroxide catalyzed by nickel complexes supported by pyridylalkylamine ligands.

    Science.gov (United States)

    Morimoto, Yuma; Bunno, Shuji; Fujieda, Nobutaka; Sugimoto, Hideki; Itoh, Shinobu

    2015-05-13

    Selective hydroxylation of benzene to phenol has been achieved using H2O2 in the presence of a catalytic amount of the nickel complex [Ni(II)(tepa)](2+) (2) (tepa = tris[2-(pyridin-2-yl)ethyl]amine) at 60 °C. The maximum yield of phenol was 21% based on benzene without the formation of quinone or diphenol. In an endurance test of the catalyst, complex 2 showed a turnover number (TON) of 749, which is the highest value reported to date for molecular catalysts in benzene hydroxylation with H2O2. When toluene was employed as a substrate instead of benzene, cresol was obtained as the major product with 90% selectivity. When H2(18)O2 was utilized as the oxidant, (18)O-labeled phenol was predominantly obtained. The reaction rate for fully deuterated benzene was nearly identical to that of benzene (kinetic isotope effect = 1.0). On the basis of these results, the reaction mechanism is discussed. PMID:25938800

  8. A solid phase microextraction coating based on ionic liquid sol-gel technique for determination of benzene, toluene, ethylbenzene and o-xylene in water samples using gas chromatography flame ionization detector.

    Science.gov (United States)

    Sarafraz-Yazdi, Ali; Vatani, Hossein

    2013-07-26

    Ionic liquid mediated sol-gel sorbents for head-space solid phase microextraction (HS-SPME) were developed for the extraction of benzene, toluene, ethylbenzene and o-xylene (BTEX) compounds from water samples in ultra-trace levels. The analytes were subsequently analyzed with gas chromatography coupled to flame ionization detector (GC-FID). Three different coating fibers were prepared including: poly(dimethylsiloxane) (PDMS), coating prepared from poly(dimethylsiloxane) in the presence of ionic liquid as co-solvent and conditioned at a higher temperature than decomposition temperature of ionic liquid (PDMS-IL-HT) and coating prepared from poly(dimethylsiloxane) in the presence of ionic liquid as co-solvent and conditioned at a lower temperature than decomposition temperature of ionic liquid (PDMS-IL-LT). Prepared fibers demonstrate many advantages such as high thermal and chemical stabilities due to the chemical bonding of the coatings with the silanol groups on the fused-silica surface fiber. These fibers have shown long life time up to 180 extractions. The scanning electron micrographs of the fibers surfaces revealed that addition of ionic liquid into the sol solution during the sol-gel process increases the fiber coating thickness, affects the form of fiber structure and also leaves high pores in the fiber surface that cause high surface area and therefore increases sample capacity of the fibers. The important parameters that affect the extraction efficiency are desorption temperature and time, sample volume, extraction temperature, extraction time, stirring speed and salt effect. Therefore these factors were investigated and optimized. Under optimal conditions, the dynamic linear range with PDMS-IL-HT, PDMS and PDMS-IL-LT fibers were 0.3-200,000; 50-200,000 and 170-150,000pgmL(-1) and the detection limits (S/N=3) were 0.1-2 and 15-200 and 50-500pgmL(-1), and limit of quantifications (S/N=10) were 0.3-8 and 50-700 and 170-1800, respectively. The relative standard deviations (RSD) for one fiber (repeatability) (n=5), were obtained from 3.1 up to 5.4% and between fibers or batch to batch (reproducibility) (n=3) in the range of 3.8-8.5% for three fibers. The developed method was successfully applied to the real water samples while the relative recovery percentages obtained for the spiked water samples at 20pgmL(-1) were from 91.2 to 103.3%. PMID:23582769

  9. 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.

  10. 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.

  11. 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)

  12. 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

    International Nuclear Information System (INIS)

    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)

  13. Molecular orbital studies (hardness, chemical potential, electronegativity and electrophilicity), vibrational spectroscopic investigation and normal coordinate analysis of 5-{1-hydroxy-2-[(propan-2-yl)amino]ethyl}benzene-1,3-diol

    Science.gov (United States)

    Muthu, S.; Renuga, S.

    2014-01-01

    FT-IR and FT-Raman spectra of 5-{1-hydroxy-2-[(propan-2-yl) amino] ethyl} benzene-1,3-diol (abbrevi- 54 ated as HPAEBD) were recorded in the region 4000-450 cm-1 and 4000-100 cm-1 respectively. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (B3LYP) and HF method with 6-31 G(d,p) as basis set. The theoretical wave numbers were scaled and compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated Potential energy distribution (PED). Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ? antibonding orbitals and E (2) energies confirm the occurrence of intra molecular charge transfer (ICT) within the molecule. The molecule orbital contributions were studied by using the total (TDOS), sum of ? and ? electron (??DOS) density of States. Mulliken population analysis of atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule. The electron density-based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or reactivity site in this compound. On the basis of vibrational analyses, the thermodynamic properties of title compound at different temperatures have been calculated.

  14. 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 inhibitadation 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

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

    OpenAIRE

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

    2004-01-01

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

  17. Excess Molar Volumes of (Octane + Benzene, or + Toluene, or + 1,3-Xylene, or 1,3,5-Trimethylbenzene) at Temperatures between (298.15 K and 328.15) K.

    Czech Academy of Sciences Publication Activity Database

    Morávková, Lenka; Linek, Jan

    2008-01-01

    Ro?. 40, ?. 4 (2008), s. 671-676. ISSN 0021-9614 R&D Projects: GA ?R(CZ) GA104/06/0656 Institutional research plan: CEZ:AV0Z40720504 Keywords : octane * benzene * excess volume Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.876, year: 2008

  18. 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

  19. Ethyl 2-acetylhydrazono-2-phenylacetate

    Directory of Open Access Journals (Sweden)

    Liang-Zhong Xu

    2008-01-01

    Full Text Available The title compound, C12H14N2O3, was synthesized as an intermediate for the synthesis of metamitron. The benzene ring forms dihedral angles of 86.3?(2 and 10.0?(3° with the ethyl group and the acetylimino plane, respectively. The crystal structure involves intermolecular C—H...O and N—H...O hydrogen bonds.

  20. Biodegradation of Benzene by Halophilic and Halotolerant Bacteria under Aerobic Conditions

    OpenAIRE

    A. Nicholson, Carla; Z. Fathepure, Babu

    2004-01-01

    A highly enriched halophilic culture was established with benzene as the sole carbon source by using a brine soil obtained from an oil production facility in Oklahoma. The enrichment completely degraded benzene, toluene, ethylbenzene, and xylenes within 1 to 2 weeks. Also, [14C]benzene was converted to 14CO2, suggesting the culture's ability to mineralize benzene. Community structure analysis revealed that Marinobacter spp. were the dominant members of the enrichment.

  1. Radiolysis of Aqueous Toluene Solutions

    International Nuclear Information System (INIS)

    Aqueous toluene solutions have been irradiated with Co ?-rays. In unbuffered solutions the various cresol isomers are formed in a total yield of 0.45, 0.87 and 0.94 molecules/100 eV absorbed energy in argon-, N2O- and air - saturated solutions, respectively. The yields are reduced in acid (pH 3) solutions (G 0.14, 0.14 and 0.52, respectively) but the reduction is compensated by the formation of 1,2-di-phenylethane in yields of 0.49 and 1.60 in argon- and N2O-saturated solutions, respectively. Benzyl radicals are formed through an acid catalysed water elimination reaction from the initially formed hydroxymethylcyclohexadienyl radical. Phenyltolylmethanes, dimethylbiphenyls and partly reduced dimers are also formed during the radiolysis. Hydrogen is formed in the same yield as the molecular yield, g(H2). Xylene isomers and benzene are formed in trace quantities. The most remarkable effects of the addition of Fe(III) ions to deaerated acid toluene solutions are the formation of benzyl alcohol and benzaldehyde and an increase in the yield of 1,2-diphenylethane

  2. Icosapent Ethyl

    Science.gov (United States)

    ... are allergic to icosapent ethyl; fish, including shellfish (clams, scallops, shrimp, lobster, crayfish, crab, oyster, mussels, others); ... water pills'); estrogen-containing contraceptives (birth control pills, patches, rings, and injections); or estrogen replacement therapy. Your ...

  3. 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.

  4. 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.

  5. 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.)

  6. Chronic neurobehavioural effects of toluene.

    OpenAIRE

    Foo, S. C.; Jeyaratnam, J.; Koh, D.

    1990-01-01

    Neurobehavioural tests were undertaken by 30 female workers exposed to toluene and matched controls with low occupational exposure to toluene. The environmental air levels (TWA) of toluene was 88 ppm for the exposed workers and 13 ppm for the controls. The toluene in blood concentrations for the exposed workers was 1.25 mg/l and for the controls 0.16 mg/l. Statistically significant differences between workers exposed to toluene and controls in neurobehavioural tests measuring manual dexterity...

  7. 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.

  8. A novel solid-phase microextraction using coated fiber based sol-gel technique using poly(ethylene glycol) grafted multi-walled carbon nanotubes for determination of benzene, toluene, ethylbenzene and o-xylene in water samples with gas chromatography-flame ionization detector.

    Science.gov (United States)

    Sarafraz-Yazdi, Ali; Amiri, Amirhassan; Rounaghi, Gholamhossein; Hosseini, Hossein Eshtiagh

    2011-08-26

    In this study, poly(ethylene glycol) (PEG) grafted onto multi-walled carbon nanotubes (PEG-g-MWCNTs) were synthesized by the covalent functionalization of MWCNTs with hydroxyl-terminated PEG chains. For the first time, functionalized product of PEG-g-MWCNTs was used as selective stationary phase to prepare the sol-gel solid-phase microextraction (SPME) fiber in combination with gas chromatography-flame ionization detector (GC-FID) for the determination of ultra-trace levels of benzene, toluene, ethylbenzene and o-xylene (BTEX) in real water samples. The PEG-g-MWCNTs were characterized by Fourier transform infrared spectra and also thermo-gravimetric analysis, which verified that PEG chains were grafted onto the surface of the MWCNTs. The scanning electron micrographs of the fiber surface revealed a highly porous structure which greatly increases the surface area for PEG-g-MWCNTs sol-gel coating. This fiber demonstrated many inherent advantages, the main being the strong anchoring of the coating to the fused silica resulting from chemical bonding with the silanol groups on the fused-silica fiber surface. The new PEG-g-MWCNTs sol-gel fiber is simple to prepare, robust, with high thermal stability and long lifetime, up to 200 extractions. Important parameters influencing the extraction efficiency 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 (S/N=3) were in the range of 0.6-3 pg mL(-1) and the limits of quantification (S/N=10) between 2 and 10 pg mL(-1). The relative standard deviations (RSDs) for one fiber (repeatability) (n=5) were obtained from 4.40 up to 5.75% and between fibers or batch to batch (n=3) (reproducibility) in the range of 4.31-6.55%. The developed method was successfully applied to real water samples while the relative recovery percentages obtained for the spiked water samples at 20 pg mL(-1) were from 90.21 to 101.90%. PMID:21782185

  9. CFD SIMULATIONS OF BENZENE –TOLUENE 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.

  10. A novel toluene-3-monooxygenase pathway cloned from Pseudomonas pickettii PKO1.

    OpenAIRE

    Olsen, R. H.; Kukor, J. J.; Kaphammer, B.

    1994-01-01

    Plasmid pRO1957, which contains a 26.5-kb fragment from the chromosome of Pseudomonas pickettii PKO1, allows P. aeruginosa PAO1 to grow on toluene or benzene as a sole carbon and energy source. A subclone of pRO1957, designated pRO1966, when present in P. aeruginosa PAO1 grown in lactate-toluene medium, accumulates m-cresol in the medium, indicating that m-cresol is an intermediate of toluene catabolism. Moreover, incubation of such cells in the presence of 18O2 followed by gas chromatography...

  11. 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.

  12. Toluene embryopathy: two new cases.

    OpenAIRE

    Hersh, J. H.

    1989-01-01

    Toluene embryopathy is characterised by microcephaly, central nervous system dysfunction, attentional deficits and hyperactivity, developmental delay with greater language deficits, minor craniofacial and limb anomalies, and variable growth deficiency. Previously, three affected children, born to women who inhaled toluene regularly throughout pregnancy, have been reported. Two more cases are described emphasising the importance of toluene as a potential human teratogen.

  13. 40 CFR 261.31 - Hazardous wastes from non-specific sources.

    Science.gov (United States)

    2010-07-01

    ...solvents: Xylene, acetone, ethyl acetate, ethyl benzene, ethyl ether, methyl isobutyl ketone, n-butyl alcohol, cyclohexanone...spent non-halogenated solvents: Toluene, methyl ethyl ketone, carbon disulfide, isobutanol,...

  14. Demand boom boosts ethyl, butyl acetate

    International Nuclear Information System (INIS)

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

  15. Ethyl 2-acetyl­hydrazono-2-phenyl­acetate

    OpenAIRE

    Liang-Zhong Xu; Xu Yi; Guang-Wei An; Gong-Sheng Zhang; Chun-Fang Li

    2007-01-01

    The title compound, C12H14N2O3, was synthesized as an intermediate for the synthesis of metamitron. The benzene ring forms dihedral angles of 86.3?(2) and 10.0?(3)° with the ethyl group and the acetylimino plane, respectively. The crystal structure involves intermolecular C—H...O and N—H...O hydrogen bonds.

  16. 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.

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

    Science.gov (United States)

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

    2010-05-01

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

  18. Anaerobic degradation of toluene and xylene by aquifer microorganisms under sulfate-reducing conditions

    International Nuclear Information System (INIS)

    Toluene and the three isomers of xylene were completely mineralized to CO2 and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was gasoline-contaminated sediment from Seal Beach, California. Evidence confirming that sulfate was the terminal electron acceptor is presented. Benzene and ethylbenzene were not degraded under the experimental conditions used. Successive transfers of the mixed cultures that were enriched from aquifer sediments retained the ability to degrade to toluene and xylenes. Greater than 90% of 14C-labeled toluene or 14C-labeled o-xylene was mineralized to 14CO2. The doubling time for the culture grown on toluene or m-xylene was about 20 days, and the cell yield was about 0.1 to 0.14 g of cells (dry weight) per g of substrate. The accumulation of sulfide in the cultures as a result of sulfate reduction appeared to inhibit degradation of aromatic hydrocarbons

  19. Benzene from catalytic hydrocracking

    Energy Technology Data Exchange (ETDEWEB)

    Cindric, M.

    1982-01-01

    The physiochemical and explosion properties of benzene, produced in the catalytic hydrocracking process at the Bosanski Brod petroleum refineries, were studied. The fractionation and group chemical composition of light (specific weight 0.6487) and heavy fractions (specific weight 0.7024) are given. The explosion characteristics are investigated together with the sensitivity to an injection of 6 grams explosion additives per one liter benzene. A heavy benzene fraction should be subjected to additional treatment in a catalytic reforming assembly. A variation in benzene's octane characteristics when compounded in a reformate of 10-40 percent light or heavy hydrocracking benzene fractions is studied. Graphs are designed which reflect an increase in the octane number of light (from 83 to 94) and heavy (from 63 to 80) benzene fractions when tetraethyllead (0.1-0.7 grams of lead to one liter of benzene) is injected. It is demonstrated that the hydrocracking catalytic process makes is possible to produce high quality benzene for carburator motors and a heavy fraction, which is a valuable raw material for hydrocracking catalytic assemblies.

  20. 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

  1. Benzene: questions and answers

    International Nuclear Information System (INIS)

    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 beforf 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

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

    Science.gov (United States)

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

    1985-01-01

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

  3. Medicolegal Aspects of Blood-Urine Toluene and Urinary Ortho-Cresol Concentrations in Toluene Exposure

    OpenAIRE

    Akgu?r, Serap A.

    2001-01-01

    Toluene is a widely used solvent in different industrial areas and has a depressant effect on the central nervous system. In medicolegal cases, for the possible influence of toluene on actions or conditions prior to death, a reliable indicator of exposure must be precisely investigated. We developed an appropriate method for toluene analysis and investigate the blood-urine toluene levels and urinary ortho-cresol levels in toluene-exposed workers. Blood and urine toluene levels from 50 male su...

  4. Ethyl 2-acetyl-hydrazono-2-phenyl-acetate.

    Science.gov (United States)

    Xu, Liang-Zhong; Yi, Xu; An, Guang-Wei; Zhang, Gong-Sheng; Li, Chun-Fang

    2007-01-01

    The title compound, C(12)H(14)N(2)O(3), was synthesized as an inter-mediate for the synthesis of metamitron. The benzene ring forms dihedral angles of 86.3?(2) and 10.0?(3)° with the ethyl group and the acetyl-imino plane, respectively. The crystal structure involves inter-molecular C-H?O and N-H?O hydrogen bonds. PMID:21200890

  5. Ethyl 2-acetyl­hydrazono-2-phenyl­acetate

    Science.gov (United States)

    Xu, Liang-Zhong; Yi, Xu; An, Guang-Wei; Zhang, Gong-Sheng; Li, Chun-Fang

    2008-01-01

    The title compound, C12H14N2O3, was synthesized as an inter­mediate for the synthesis of metamitron. The benzene ring forms dihedral angles of 86.3?(2) and 10.0?(3)° with the ethyl group and the acetyl­imino plane, respectively. The crystal structure involves inter­molecular C—H?O and N—H?O hydrogen bonds. PMID:21200890

  6. 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.

  7. Ethyl 4-chloro-2?-fluoro-3-hydroxy-5-methylbiphenyl-2-carboxylate

    Directory of Open Access Journals (Sweden)

    Muhammad Adeel

    2011-09-01

    Full Text Available In the title compound, C16H14ClFO3, the dihedral angle between the mean planes of the two benzene rings is 71.50?(5°. Due to an intramolecular O—H...O hydrogen bond between the hydroxy group and the carbonyl O atom of the ethyl ester group, the ethyl ester group lies within the ring plane. The crystal structure is consolidated by intermolecular C—H...O and C—H...F interactions.

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

    International Nuclear Information System (INIS)

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

  9. Ethyl 2-(3-ethyl­sulfinyl-5-methyl-1-benzo­furan-2-yl)acetate

    OpenAIRE

    Hong Dae Choi; Pil Ja Seo; Byeng Wha Son; Uk Lee

    2009-01-01

    The title compound, C15H18O4S, was prepared by the oxidation of ethyl 2-(3-ethylsulfanyl-5-methyl-1-benzofuran-2-yl)acetate with 3-chloroperoxybenzoic acid. The crystal structure is stabilized by aromatic ?–? interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.655?(3)?Å] and by three intermolecular C—H...O non-classical hydrogen bonds.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Sohail Saeed

    2011-02-01

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

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

    International Nuclear Information System (INIS)

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

  13. 27 CFR 21.132 - Toluene.

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2010-04-01 false Toluene. 21.132 Section 21.132 Alcohol...Specifications for Denaturants § 21.132 Toluene. (a) Distillation range. ...Standard No. D 362-75 for industrial grade toluene; for incorporation by reference,...

  14. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

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

    International Nuclear Information System (INIS)

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

  16. 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.

  17. New method for spectrophotometric determination of benzene in air

    Energy Technology Data Exchange (ETDEWEB)

    Verma, P.; Gupta, V.K.

    1984-01-01

    A new spectrophotometric method for the determination of benzene in air is described. The method is based upon the nitration of benzene to m-dinitrobenzene and subsequent reduction to m-phenylenediamine. m-Phenylenediamine is determined by diazotization-coupling reaction. ..cap alpha..-Naphthol is used as a coupling reagent. Beer's law is obeyed in the range of 10-80 ..mu..g of m-dinitribenzene per 25 mL sample. The dye shows a wavelength of maximum absorption at 530 nm. The dye is stable for approx. 30 h. Toluene, the major interferent, can be separated. Beer's law, sensitivity, reproducibility, and other reaction conditions such as time, temperature, and acidity were studied. Formation of stable dye is the main advantage of the method over the butanone method for benzene, in which the colored complex is stable for only 5 min. It is possible to determine traces of benzene (0.05-0.30 ..mu..g/mL) by extracting the azo dye in 10 mL iso-amyl alcohol; this also increases the stability of the dye up to 42 h. 11 references, 4 tables.

  18. 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.

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

    Science.gov (United States)

    Cinar, Mehmet; Karabacak, Mehmet

    2013-03-01

    The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and non-linear optical properties of ethyl trans-alfa-cyano-3-indole-acrylate (C14H12N2O2) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman in the range of 4000-400 cm-1 and 4000-10 cm-1, respectively. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The 1H, 13C and DEPT NMR spectra were recorded in DMSO solution, and gauge-invariant atomic orbitals (GIAO) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were recorded in the range of 200-800 nm in various solvents of different polarity (acetone, benzene, chlorobenzene, chloroform, DMSO, ethanol, methanol and toluene). Solvent effects were calculated using TD-DFT and CIS method. To investigate the non-linear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations.

  20. 1-Ethyl-3-(2,4,6-trimethyl­phen­yl)imidazolium tetra­fluoro­borate

    OpenAIRE

    Jin-Tao Guan; Jian-Guo Hou; Zhi-Yong Zhang; Si-Yin Zhao

    2010-01-01

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

  1. (2E-2-Benzylidene-4-ethyl-3,4-dihydronaphthalen-1(2H-one

    Directory of Open Access Journals (Sweden)

    Mohamed Akhazzane

    2011-07-01

    Full Text Available In the title compound, C19H18O, the exocyclic C=C double bond has an E configuration. The ethyl substituent on the cyclohexanone ring is in an axial position. The cyclohexanone ring adopts a half-chair conformation, presumably due to conjugation in the benzene ring.

  2. 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.

  3. ASPEN HYSYS SIMULATION AND COMPARISON BETWEEN ORGANIC SOLVENTS (SULFOLANE AND DMSO) USED FOR BENZENE EXTRACTION

    OpenAIRE

    Zaiz, T.; Lanez, H.; Kechida, B.

    2013-01-01

    Due to the high increase of the production of aromatic hydrocarbons: benzene, toluene and xylenes BTX from oil because of the large activity of their big markets especially with the availability of great quantities of these aromatic fractions in the oil. This study has two main parts the first presents a general vision of the aromatic hydrocarbons, the second is going to focus on the liquid-liquid extraction with the selected solvents as a separation method. The solvent selection depends on m...

  4. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  5. Recurrent asthma induced by toluene diisocyanate.

    OpenAIRE

    Banks, D. E.; Rando, R. J.

    1988-01-01

    A worker developed toluene diisocyanate induced asthma in 1974. On reassessment, 11 years after leaving the chemical plant where toluene diisocyanate was produced, he had no respiratory symptoms and normal bronchial reactivity in response to methacholine, and showed no reaction when challenged with a subirritant concentration of toluene diisocyanate. He developed asthma within five months of returning to the workplace. Repeat challenge testing showed bronchial hyperreactivity to methacholine ...

  6. Biodegradation of toluene in a trickling filter

    OpenAIRE

    Peixoto, J.; Mota, M.

    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...

  7. Composition of Toluene-Degrading Microbial Communities from Soil at Different Concentrations of Toluene

    OpenAIRE

    Hubert, Casey; Shen, Yin; Voordouw, Gerrit

    1999-01-01

    Toluene-degrading bacteria were isolated from hydrocarbon-contaminated soil by incubating liquid enrichment cultures and agar plate cultures in desiccators in which the vapor pressure of toluene was controlled by dilution with vacuum pump oil. Incubation in desiccators equilibrated with either 100, 10, or 1% (wt/wt) toluene in vacuum pump oil and testing for genomic cross-hybridization resulted in four genomically distinct strains (standards) capable of growth on toluene (strains Cstd1, Cstd2...

  8. 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

  9. 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.

  10. Impact of coexposure on toluene biomarkers in rats.

    Science.gov (United States)

    Cosnier, Frédéric; Nunge, Hervé; Brochard, Céline; Burgart, Manuella; Rémy, Aurélie; Décret, Marie-Josèphe; Cossec, Benoît; Campo, Pierre

    2014-03-01

    1.?Toluene (TOL) is widely used in industry. Occupational exposure to TOL is commonly assessed using TOL in blood, hippuric acid and ortho-cresol. Levels of these biomarkers may depend on factors potentially interfering with TOL biotransformation, such as the presence of other solvents in the workplace. Mercapturic acids (MAs) could be an alternative to the "traditional" TOL biomarkers. 2.?This study aims (1) to investigate in rat the effects of an exposure to vapours mixtures on the TOL metabolism, and (2) to assess how well MAs performed in these contexts compared to the traditional TOL biomarkers. 3.?Rats were exposed by inhalation to binary mixtures of TOL with n-butanol (BuOH), ethyl acetate (EtAc), methyl ethyl ketone (MEK) or xylenes (XYLs); biological exposure indicators were then measured. 4.?Depending on the compounds in the mixture and their concentrations, TOL metabolism was accelerated (with BuOH), unchanged (with EtAc) or inhibited (with XYLs and MEK). Inhibition leads to an increase in blood TOL concentrations, even at authorized atmospheric concentrations, which may potentiate the effect of TOL. 5.?MAs excretions are little affected by coexposure scenarios, their levels correlating well with atmospheric TOL levels. They could thus be suitable bioindicators of atmospheric TOL exposure. PMID:24015909

  11. 21 CFR 520.580 - Dichlorophene and toluene capsules.

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 false Dichlorophene and toluene capsules. 520.580 Section 520...DRUGS § 520.580 Dichlorophene and toluene capsules. (a) Specifications. ...milligrams of dichlorophene and 60 milligrams of toluene or multiples thereof. (b)...

  12. Benzoxyl radical decomposition kinetics: formation of benzaldehyde + H, phenyl + CH2O, and benzene + HCO.

    Science.gov (United States)

    da Silva, Gabriel; Bozzelli, Joseph W

    2009-06-25

    The kinetics of benzoxyl radical decomposition was studied using ab initio computational chemistry and RRKM rate theory. The benzoxyl radical is an important but short-lived intermediate in the combustion of toluene and other alkylated aromatic hydrocarbons. A theoretical study of the thermochemistry and kinetics to products over a range of temperatures and pressures for benzoxyl decomposition is reported. Ab initio calculations with the G3X theoretical method reveal low-energy pathways from the benzoxyl radical to benzaldehyde + H and the phenyl radical + formaldehyde (CH(2)O), as well as a novel mechanism to benzene + the formyl radical (HC(*)O). RRKM simulations were performed for benzoxyl decomposition as a function of temperature and pressure. Benzaldehyde formation constitutes more than 80% of the total reaction products at temperatures below 1000 K, decreasing to around 50% at 2000 K. Formation of benzene + HC(*)O and phenyl + CH(2)O is of similar importance, each accounting for 5-10% of the decomposition products at around 1000 K, increasing to 20-30% at 2000 K. The results presented here should lead to improved kinetic models for the oxidation of alkylated aromatic hydrocarbons, particularly for the formation of benzene as a direct oxidation product of toluene. Re-evaluation of the phenyl radical heat of formation leads us to suggest a benzene C-H bond dissociation energy in the range of 113.5-114.5 kcal mol(-1). PMID:19496593

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

    International Nuclear Information System (INIS)

    Highlights: ? Measurements of activity coefficients at infinite dilution using GLC. ? Forty-two organic solvents and water in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate. ? High selectivity for heptane/thiophene. ? Possible entrainer for different separation processes with water. ? The excess thermodynamic functions and the gas–liquid partition coefficients were calculated. - Abstract: The activity coefficients at infinite dilution, ?13?, for 43 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine, and 1-nitropropane in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][MeSO3] were determined by gas–liquid chromatography at six temperatures within the range (308.15 to 358.15) K. The interaction of these 42 organic compounds and water with the ionic liquid were described with the partial molar excess Gibbs free energy, ?G1E,?, enthalpy ?H1E,?, and entropy Tref?S1E,? at infinite dilution, calculated from the experimental ?13? values obtained over the temperature range. The gas–liquid partition coefficients, KL were calculated for all solutes. The values of the selectivity for few separation problems as heptane/toluene, cyclohexane/benzene, heptane/xylenes and heptane/nd heptane/thiophene were calculated from ?13? and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [EMIM]+ cation. Comparison with the results published earlier for [EMIM][MeSO3] show much lower selectivities in the discussed separation problems. By contrast with the former measured ILs [EMIM][MeSO3] reveals the average selectivity for the separation of aromatics/aliphatics and low capacity for benzene. An interesting high value of selectivity was observed in the separation of thiophene/aliphatics. Very high values of selectivity may be expected in the separation of the azeotropic systems including water. The density of [EMIM][MeSO3] within temperature range from (298.15 to 358.15) K was measured and compared to the literature values.

  14. Methane from benzene in argon dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Das, Tomi Nath, E-mail: tndas@barc.gov.in [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Dey, G.R., E-mail: grdey@barc.gov.in [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2013-03-15

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

  15. Methane from benzene in argon dielectric barrier discharge

    International Nuclear Information System (INIS)

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

  16. Regrading 'Chemial toxicity of tritiated toluene'

    International Nuclear Information System (INIS)

    When determining the inhalation hazards associated with labelled compounds, such as tritiated toluene, it is necessary to consider chemical toxicity as well as radiotoxicity when handling these compounds. In the case of tritiated toluene chemical toxicity could result in neurological impairment. (U.K.)

  17. Analysis of structure, function, and activity of a benzene-degrading microbial community.

    Science.gov (United States)

    Jechalke, Sven; Franchini, Alessandro G; Bastida, Felipe; Bombach, Petra; Rosell, Mónica; Seifert, Jana; von Bergen, Martin; Vogt, Carsten; Richnow, Hans H

    2013-07-01

    We identified phylotypes performing distinct functions related to benzene degradation in complex microbial biofilms from an aerated treatment pond containing coconut textile. RNA- and protein-stable isotope probing (SIP) and compound-specific stable isotope analysis were applied to delineate bacteria and predominant pathways involved in the degradation of benzene. In laboratory microcosms, benzene was degraded at rates of ? 11 ?M per day and per gram coconut textile under oxic conditions. Carbon isotope fractionation with isotopic enrichment factors (?) of -0.6 to -1‰ and no significant hydrogen isotope fractionation indicated a dihydroxylation reaction for the initial ring attack. The incubation with [(13)C?]-benzene led to (13)CO? formation accompanied by (13)C-labeling of RNA and proteins of the active biomass. Phylogenetic analysis of the (13)C-labeled RNA revealed that phylotypes related to Zoogloea, Ferribacterium, Aquabacterium, and Hydrogenophaga within the Betaproteobacteria predominantly assimilated carbon from benzene. Although the phylogenetic classification of identified (13)C-labeled proteins was biased by the incomplete metagenome information of public databases, it matched with RNA-SIP results at genus level. The detection of (13)C-labeled proteins related to toluene dioxygenase and catechol 2,3-dioxygenase suggests benzene degradation by a dihydroxylation pathway with subsequent meta-cleavage of formed catechol. PMID:23398624

  18. Ethyl 1-acetyl-1H-indole-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Tasneem Siddiquee

    2009-08-01

    Full Text Available The title compound, C13H13NO3, was synthesized by acetylation of ethyl 1H-indole-3-carboxylate. The aromatic ring system of the molecule is essentially planar, but the saturated ethyl group is also located within this plane and the overall r.m.s. deviation from planarity is only 0.034?Å. Pairs of C—H...O interactions connect molecules into chains along the diagonal of the unit cell. Molecules also form weakly connected dimers via ?...? stacking interactions of the indole rings with centroid–centroid separations of 3.571?(1?Å. C—H...? interactions between methylene and methyl groups and the indole and benzene ring complete the directional intermolecular interactions found in the crystal structure.

  19. Ethyl 2-[3-(4-nitrobenzoylthioureido]benzoate

    Directory of Open Access Journals (Sweden)

    Sohail Saeed

    2010-04-01

    Full Text Available In the title compound, C17H15N3O5S, the nitro and thioureido groups are twisted by 7.2?(7 and 21.4?(2°, respectively, from the nitrobenzene ring plane whereas the thioureido and the ethyl ester group make dihedral angles of 43.0?(1 and 18.0?(2°, respectively, with the benzene rings to which they are attached. Intramolecular N—H...O hydrogen-bonding interactions are observed. In the crystal, intermolecular N—H...O hydrogen bonds connect the molecules into chains running along the a axis.

  20. 1-{Phen-yl[1-(p-tol-yl)ethyl-amino]meth-yl}-2-naphthol.

    Science.gov (United States)

    Li, Yong Hua; Zhao, Min Min; Zhang, Yuan

    2008-01-01

    The title compound, C(26)H(25)NO, was obtained via a one-pot synthesis from the reaction of 2-naphthol, 1-(p-tol-yl)ethyl-amine, p-toluene-sulfonic acid and benzaldehyde. There are three mol-ecules per asymmetric unit, all having similar conformations. There are intra-molecular O-H?N and C-H?O hydrogen bonds, with only van der Waals forces found between mol-ecules. PMID:21201203

  1. Aerobic cometabolism of trichloroethene and cis-dichloroethene with benzene and chlorinated benzenes as growth substrates.

    Science.gov (United States)

    Elango, Vijai; Kurtz, Harry D; Freedman, David L

    2011-06-01

    Using inoculum from a microcosm study that exhibited aerobic transformation of cis-1,2-dichloroethene (cDCE) and trichloroethene (TCE) commensurate with biodegradation of monoaromatic compounds, enrichment cultures were developed by providing benzene, chlorobenzene (CB), dichlorobenzene (DCB) isomers and 1,2,4-trichlorobenzene as carbon and energy sources. Isolates that grow on benzene, CB, 1,2-DCB and 1,3-DCB were identified as Rhodococcus, Ralstonia, Variovorax and Ralstonia spp., respectively. Cometabolic transformation of cDCE and TCE by resting cells was demonstrated. Transformation capacities (T(c)=0.47-1.0 ?g TCE mg(-1)biomass; 1.3-5.3 ?g cDCE mg(-1)biomass), transformation yields (T(y)=0.18-0.27 ?g TCE mg(-1)substrate; 0.46-2.1 ?g cDCE mg(-1)substrate), and pseudo-first-order cometabolic degradation rate constants (0.00081-0.0031 L mg TCE(-1)d(-1); 0.0012-0.030 L mg cDCE(-1)d(-1)) for resting cells grown on benzene, CB, 1,2-DCB and 1,3-DCB were generally lower in comparison to phenol and toluene-grown isolates. Cometabolic transformation of cDCE and TCE also occurred while the cultures concurrently consumed their growth substrate (T(c)(')=0.15-0.33 ?g TCE mg(-1)biomass; 4.9-11 ?g cDCE mg(-1)biomass; T(y)(')=0.06-0.11 ?g TCE mg(-1)substrate; 1.7-4.6 ?g cDCE mg(-1)substrate), a condition that is more likely to be encountered in situ compared to cometabolic transformations by resting cells. This study is the first to report transformation rates, capacities, and yields for cometabolism of cDCE and TCE during aerobic growth on benzene, CB, 1,2-DCB and 1,3-DCB. This type of information is needed to predict the potential for natural attenuation when these compounds occur as co-contaminants. PMID:21531438

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

    Directory of Open Access Journals (Sweden)

    Gema Mikulskiene

    2006-01-01

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

  3. Ethyl diazoacetate synthesis in flow

    OpenAIRE

    Delville, Mariëlle M E; van Hest, Jan C. M.; Rutjes, Floris P.J.T.

    2013-01-01

    Ethyl diazoacetate is a versatile compound in organic chemistry and frequently used on lab scale. Its highly explosive nature, however, severely limits its use in industrial processes. The in-line coupling of microreactor synthesis and separation technology enables the synthesis of this compound in an inherently safe manner, thereby making it available on demand in sufficient quantities. Ethyl diazoacetate was prepared in a biphasic mixture comprising an aqueous solution of glycine ethyl este...

  4. 1-Benzyl-5-ethyl-5-hydroxy-1H-pyrrol-2(5H-one

    Directory of Open Access Journals (Sweden)

    Yan-Jiao Gao

    2013-07-01

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

  5. Collision lifetimes of polyatomic molecules at low temperatures: Benzene–benzene vs benzene–rare gas atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jie; Krems, Roman V. [Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada); Li, Zhiying [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2014-10-28

    We use classical trajectory calculations to study the effects of the interaction strength and the geometry of rigid polyatomic molecules on the formation of long-lived collision complexes at low collision energies. We first compare the results of the calculations for collisions of benzene molecules with rare gas atoms He, Ne, Ar, Kr, and Xe. The comparison illustrates that the mean lifetimes of the collision complexes increase monotonically with the strength of the atom–molecule interaction. We then compare the results of the atom–benzene calculations with those for benzene–benzene collisions. The comparison illustrates that the mean lifetimes of the benzene–benzene collision complexes are significantly reduced due to non-ergodic effects prohibiting the molecules from sampling the entire configuration space. We find that the thermally averaged lifetimes of the benzene–benzene collisions are much shorter than those for Xe with benzene and similar to those for Ne with benzene.

  6. Collision lifetimes of polyatomic molecules at low temperatures: Benzene–benzene vs benzene–rare gas atom collisions

    International Nuclear Information System (INIS)

    We use classical trajectory calculations to study the effects of the interaction strength and the geometry of rigid polyatomic molecules on the formation of long-lived collision complexes at low collision energies. We first compare the results of the calculations for collisions of benzene molecules with rare gas atoms He, Ne, Ar, Kr, and Xe. The comparison illustrates that the mean lifetimes of the collision complexes increase monotonically with the strength of the atom–molecule interaction. We then compare the results of the atom–benzene calculations with those for benzene–benzene collisions. The comparison illustrates that the mean lifetimes of the benzene–benzene collision complexes are significantly reduced due to non-ergodic effects prohibiting the molecules from sampling the entire configuration space. We find that the thermally averaged lifetimes of the benzene–benzene collisions are much shorter than those for Xe with benzene and similar to those for Ne with benzene

  7. 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

  8. Phylogenetic and functional diversity within toluene-degrading, sulphate-reducing consortia enriched from a contaminated aquifer.

    Science.gov (United States)

    Kuppardt, Anke; Kleinsteuber, Sabine; Vogt, Carsten; Lüders, Tillmann; Harms, Hauke; Chatzinotas, Antonis

    2014-08-01

    Three toluene-degrading microbial consortia were enriched under sulphate-reducing conditions from different zones of a benzene, toluene, ethylbenzene and xylenes (BTEX) plume of two connected contaminated aquifers. Two cultures were obtained from a weakly contaminated zone of the lower aquifer, while one culture originated from the highly contaminated upper aquifer. We hypothesised that the different habitat characteristics are reflected by distinct degrader populations. Degradation of toluene with concomitant production of sulphide was demonstrated in laboratory microcosms and the enrichment cultures were phylogenetically characterised. The benzylsuccinate synthase alpha-subunit (bssA) marker gene, encoding the enzyme initiating anaerobic toluene degradation, was targeted to characterise the catabolic diversity within the enrichment cultures. It was shown that the hydrogeochemical parameters in the different zones of the plume determined the microbial composition of the enrichment cultures. Both enrichment cultures from the weakly contaminated zone were of a very similar composition, dominated by Deltaproteobacteria with the Desulfobulbaceae (a Desulfopila-related phylotype) as key players. Two different bssA sequence types were found, which were both affiliated to genes from sulphate-reducing Deltaproteobacteria. In contrast, the enrichment culture from the highly contaminated zone was dominated by Clostridia with a Desulfosporosinus-related phylotype as presumed key player. A distinct bssA sequence type with high similarity to other recently detected sequences from clostridial toluene degraders was dominant in this culture. This work contributes to our understanding of the niche partitioning between degrader populations in distinct compartments of BTEX-contaminated aquifers. PMID:24623528

  9. Carbon Doping of MgB2 by Toluene and Malic-Acid-in-Toluene

    OpenAIRE

    Bohnenstiehl, S. D.; Susner, M. A.; Yang, Y.; Collings, E. W.; Sumption, M. D.; Rindfleisch, M. A.; Boone, R.

    2010-01-01

    The decomposition of malic acid in the presence of Mg and B was studied using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) which revealed that malic acid reacted with Mg but not B. Also, the addition of toluene to dissolve malic acid followed by subsequent drying resulted in no reaction with Mg, indicating that the malic acid had decomposed during the dissolution/drying stage. The total carbon contributed by toluene versus a toluene/5 wt% mali...

  10. Major sources of benzene exposure.

    OpenAIRE

    Wallace, L.A.

    1989-01-01

    Data from EPA's TEAM Study allow us to identify the major sources of exposure to benzene for much of the U.S. population. These sources turn out to be quite different from what had previously been considered the important sources. The most important source of exposure for 50 million smokers is the mainstream smoke from their cigarettes, which accounts for about half of the total population burden of exposure to benzene. Another 20% of nationwide exposure is contributed by various personal act...

  11. Effects of Benzene on human hematopoiesis

    OpenAIRE

    Kirkeleit, Jorunn; Riise, Trond; Gjertsen, Bjørn Tore; Moen, Bente E.; Bra?tveit, Magne; Bruserud, Øystein

    2008-01-01

    Benzene, an aromatic hydrocarbon that is a natural component of crude oil and natural gas, is toxic to the blood and blood-forming organs. Epidemiological studies have established an association between benzene exposure and acute myeloid leukemia, and increasing evidence also indicates a possible association between benzene and multiple myeloma. A specific benzene-associated myelodysplastic syndrome has also been suggested. Chronic hematotoxic effects of benzene exposure, includin...

  12. Reversible toluene adsorption on monolithic carbon aerogels.

    Science.gov (United States)

    Maldonado-Hódar, Francisco J; Moreno-Castilla, Carlos; Carrasco-Marín, Francisco; Pérez-Cadenas, Agustín F

    2007-09-30

    Thirteen monolithic carbon aerogels with different pore textures were used as toluene adsorbents. Adsorption was carried out under both static and dynamic conditions. Under static conditions at 25 degrees C and at saturation, an adsorption capacity as high as 1.36 cm(3) g(-1) or 1180 mg g(-1) was obtained. Toluene adsorption was a reversible process in all carbon aerogels, and the adsorbed toluene was completely recovered by heating them at 400 degrees C. Regenerated adsorbents showed larger surface area and micropore width than the original samples, indicating that no pore blockage was produced. Adsorption under dynamic conditions at 100 degrees C was also completely reversible after at least three consecutive adsorption-desorption cycles. The ability of these carbon aerogels to reversibly adsorb toluene could be useful for their application in thermal swing adsorption or pressure swing adsorption equipment. PMID:17433536

  13. 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

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

    Directory of Open Access Journals (Sweden)

    Ai Guo Zhu

    2012-10-01

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

  15. 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.

  16. Crystal structure of azilsartan methyl ester ethyl acetate hemisolvate.

    Science.gov (United States)

    Li, Zhengyi; Liu, Rong; Zhu, Meilan; Chen, Liang; Sun, Xiaoqiang

    2015-02-01

    The title compound, C26H22N4O5 (systematic name: methyl 2-eth-oxy-1-{4-[2-(5-oxo-4,5-di-hydro-1,2,4-oxa-diazol-3-yl)phenyl]benz-yl}-1H-1,3-benzo-diazole-7-carboxyl-ate ethyl acetate hemisolvate), was obtained via cyclization of methyl (Z)-2-eth-oxy-1-{(2'-(N'-hy-droxy-carbamimido-yl)-[1,1'-biphen-yl]-4-yl)meth-yl}-1H-benzo[d]imidazole-7-carboxyl-ate with diphen-yl carbonate. There are two independent mol-ecules (A and B) with different conformations and an ethyl acetate solvent mol-ecule in the asymmetric unit. In mol-ecule A, the dihedral angle between the benzene ring and its attached oxa-diazole ring is 59.36?(17); the dihedral angle between the benzene rings is 43.89?(15) and that between the benzene ring and its attached imidazole ring system is 80.06?(11)°. The corres-ponding dihedral angles in mol-ecule B are 58.45?(18), 50.73?(16) and 85.37?(10)°, respectively. The C-O-C-Cm (m = meth-yl) torsion angles for the eth-oxy side chains attached to the imidazole rings in mol-ecules A and B are 93.9?(3) and -174.6?(3)°, respectively. In the crystal, the components are linked by N-H?N and C-H?O hydrogen bonds, generating a three-dimensional network. Aromatic ?-? stacking inter-actions [shortest centroid-centroid separation = 3.536?(3)Å] are also observed. PMID:25878884

  17. Toluene solubility in water and organic partitioning from gasoline and diesel fuel into water at elevated temperatures and pressures

    International Nuclear Information System (INIS)

    A simple and reliable system for determining the solubility and partitioning behavior of liquid fuel components in liquid water up to 250 C has been developed. The system shows good agreement with literature values at ambient temperature for the solubility of toluene and for fuel/water partitioning coefficients (Kfw). Toluene solubility increased ?23-fold by raising the temperature from ambient to 200 C but was not affected at ambient temperature by changing the pressure from 1 to 50 bar. The increases in partitioning of benzene, toluene, ethylbenzene, xylenes, and naphthalene from gasoline into liquid water with increasing temperature ranged from 10-fold for benzene to 60-fold for naphthalene when the temperature was raised from ambient to 200 C. Similarly, the increases in partitioning of polycyclic aromatic hydrocarbons from diesel fuel into liquid water ranged from ?130-fold for naphthalene to 470-fold for methylnaphthalene when the temperature was raised from ambient to 250 C. The effect of temperature on the partitioning of naphthalene into water from gasoline and from diesel fuel was similar, indicating that the fuel composition had little effect on the fuel/water partitioning behavior

  18. Session 4: Study of alkyl-aromatics hydrodealkylation reaction to orient the production of benzene from the catalytic reforming process

    Energy Technology Data Exchange (ETDEWEB)

    Toppi, S.; Thomas, C.; Sayag, C.; Brodzki, D.; Djega-Mariadassou, G. [Universite Pierre et Marie Curie, Lab. de Reactivite de Surface, UMR CNRS 7609, 75 - Paris (France); Toppi, S.; Travers, C.; Le Peltier, F. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)

    2004-07-01

    Due to more stringent environmental constraints, the benzene content in the gasoline decreases regularly and has been fixed to 1% since January 2001. In the same time, the demand in aromatics, benzene, toluene, and xylenes, for the petrochemistry continuously increases. The aim of this work is to study the hydrodealkylation reactions and particularly the benzene formation under reforming operating conditions, with the bifunctional industrial catalyst. It is, therefore, of great importance to determine the role of each function of the catalyst involved in the benzene production in order to orient the reaction by modification of the catalyst. n-propylbenzene transformation was investigated on each family of model catalysts and allowed us to propose a detailed scheme for the reaction on acidic and metallic sites. The identified reactions are: - on metallic sites: dehydrogenation, cyclisation and hydrogenolysis A detailed reaction scheme for this transformation has already been proposed involving the formation of cyclisation products and the existence of a common reactive adsorbate for the indene compounds and ethylbenzene; - on acidic sites: dehydrogenation, isomerization and cracking. The study of the cracking reactions coupled with measurements of the acidity of the catalyst, shows that benzene is the preferentially formed cracking product, on the Broensted sites of the catalyst, through a carbo-cationic mechanism. Conversely, ethylbenzene and toluene are formed through a 'radical' mechanism over the Lewis acid sites of alumina. As far as the cracking reaction leading to benzene is concerned, two compulsory steps were pointed out: the first one is the isomerization of n-propylbenzene to iso-propylbenzene, and the second one is the cracking of iso-propylbenzene into benzene. The increase of strong Broensted acidity over model acidic catalysts, has been correlated with a strong increase of the benzene formation rate, emphasizing the role of strong Broensted sites in the formation of benzene. With the bifunctional Pt-Al{sub 2}O{sub 3}-Cl catalysts, an increase of the acidity is also correlated to a strong increase of the benzene formation rate, while ethylbenzene and toluene formation rates are not affected. The introduction of Sn in this previous catalyst leads from one hand, to a decrease of the global activity and, to the other hand, when Sn content is higher than 0,1 wt% to a decrease of the formation of benzene. This latter decrease could be attributed to a modification of the Broensted acid sites through the Sn atoms interacting with the support. The studies performed on model monofunctional and bifunctional catalysts allowed us to conclude that on bifunctional catalysts, toluene and ethylbenzene are formed on metallic sites by hydrogenolysis while benzene comes from the cracking of n-propylbenzene through isopropylbenzene formation on strong Broensted acid sites. From these studies new ways for reforming catalysts preparation could be considered to limit the benzene content in the reformate and particularly, the limitation as far as possible, of the chlorine content, and may be the use of more adequate tin precursor. (authors)

  19. 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 dependenhe temperature dependence of measured viscosities for [EMIM][EtSO4]. All measured properties were detailed compared with the reported data by other author.

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

    International Nuclear Information System (INIS)

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

  1. Behavior of fullerene C60 in toluene solutions

    International Nuclear Information System (INIS)

    By using X-ray scattering method were studied the behavior of fullerene C60 in toluene solutions. It is shown that the inclusion of fullerene C60 molecules to toluene solutions leads to changing of solvent structure

  2. Neuroendocrine effects in printing workers exposed to toluene.

    OpenAIRE

    Svensson, B. G.; Nise, G; Erfurth, E M; H. Olsson

    1992-01-01

    The effect of exposure to toluene on plasma concentrations of testosterone, prolactin, luteinising (LH) and follicle stimulating (FSH) hormones was investigated in 47 rotogravure printers (time weighted average air toluene below 80 ppm; blood toluene concentration post-shift 0.19-7.99 mumol/l) and compared with a reference group. Increasing exposure concentrations of toluene (concentrations less than 5 to greater than 45 ppm) were significantly associated with decreasing plasma concentrations...

  3. Benzodiazepine-like discriminative stimulus effects of toluene vapor

    OpenAIRE

    Shelton, Keith L.; Nicholson, Katherine L.

    2013-01-01

    In vitro studies show that the abused inhalant toluene affects a number of ligand-gated ion channels. The two most consistently implicated of these are ?-aminobutyric acid type A (GABAA) receptors which are positively modulated by toluene and N-methyl-D-aspartate (NMDA) receptors which are negatively modulated by toluene. Behavioral studies also suggest an interaction of toluene with GABAA and/or NMDA receptors but it is unclear if these receptors underlie the abuse-related intoxicating effe...

  4. The effect of toluene on oxidative processes in rat blood

    OpenAIRE

    Stajkovic, Silvana S.; Borozan, Suncica Z.; GORDANA GADJANSKI-OMEROVIC

    2009-01-01

    This study was designed to investigate the effects of toluene treatment on oxidative stress in rat blood. Since toluene metabolism produces reactive oxygen and nitrogen species, it was hypothesized that the toluene treatment would: 1) provoke changes in the activities of antioxidant enzymes, 2) impair the integrity of the cell membrane and 3) induce structural changes in the plasma proteins. Female Wistar rats were treated with toluene intraperitonally, at a daily dose of 0.38 mmol/kg body we...

  5. 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 ...

  6. Micellar electrophoretic capillary chromatographic analysis of the products produced in the radiolytic oxidation of toluene and phenol

    International Nuclear Information System (INIS)

    In this paper, we consider the effect of CH3 and OH substitution on a benzene ring in directing the site of OH radical attack in oxidative processes initiated by the gamma radiolysis of aqueous solutions of phenol and toluene. The analytical method used was micellar electrophoretic capillary chromatography. This approach permits the resolution of the radiolytic products resulting from the oxidation of the hydroxycyclohexadienyl radicals initially produced by addition of ·OH to the aromatic compounds and allows one to obtain a complete mechanistic picture of the radiation chemical processes

  7. Occupational exposure to benzene in China.

    OpenAIRE

    Yin, S N; Li, Q (Qin); Liu, Y; Tian, F; Du, C.; Jin, C.

    1987-01-01

    Of a total of 528,729 workers exposed to benzene or benzene mixtures in China, 508,818 (96.23%) were examined. Altogether 2,676 cases of benzene poisoning were found, a prevalence of 0.15%. A higher prevalence of benzene poisoning was found in the cities of Hangjou, Hefei, Nanjing, Shenyang, and Xian. The geometric mean concentration of benzene in 50,255 workplaces was 18.1 mg/m3 but 64.6% of the workplaces had less than 40 mg/m3. There was a positive correlation between the prevalence of ben...

  8. Effect of solvents on the radiation-induced polymerization of ethyl and isopropyl vinyl ethers

    International Nuclear Information System (INIS)

    The effect of solvents on the radiation-induced cationic polymerization of ethyl and isopropyl vinyl ethers (EVE and IPVE, respectively) was investigated. EVE and IPVE polymerizations were carried out in bulk and in solution under superdry conditions in which polar impurities, especially water, have been reduced to negligible levels. This was accomplished by means of a sodium mirror technique using joint free baked out glass equipment and high vacuum. Plots of the monomer conversions and irradiation times were obtained for EVE and IPVE polymerizations in bulk and in benzene solution at constant monomer concentrations. The monomer concentration dependence of the polymerization rate was studied for EVE polymerization in bulk and in benzene, diethlyl ether, diglyme and methylene chloride, and for IPVE polymerization in bulk and in benzene. Solvent effect on the estimated propagating rate constants was examined for EVE and IPVE polymerization in bulk and in solution. The effect of temperature on the polymerization rate was also investigated for EVE polymerization in bulk ad in benzene, diethyl and diisopropyl ethers, methylene chloride and nitromethane, and for IPVE ploymerization in bulk and in benzene

  9. 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

  10. Ethyl diazoacetate synthesis in flow

    Directory of Open Access Journals (Sweden)

    Mariëlle M. E. Delville

    2013-09-01

    Full Text Available Ethyl diazoacetate is a versatile compound in organic chemistry and frequently used on lab scale. Its highly explosive nature, however, severely limits its use in industrial processes. The in-line coupling of microreactor synthesis and separation technology enables the synthesis of this compound in an inherently safe manner, thereby making it available on demand in sufficient quantities. Ethyl diazoacetate was prepared in a biphasic mixture comprising an aqueous solution of glycine ethyl ester, sodium nitrite and dichloromethane. Optimization of the reaction was focused on decreasing the residence time with the smallest amount of sodium nitrite possible. With these boundary conditions, a production yield of 20 g EDA day?1 was achieved using a microreactor with an internal volume of 100 ?L. Straightforward scale-up or scale-out of microreactor technology renders this method viable for industrial application.

  11. A quantitative method for estimating dermal benzene absorption from benzene-containing hydrocarbon liquids.

    Science.gov (United States)

    Petty, Stephen E; Nicas, Mark; Boiarski, Anthony A

    2011-01-01

    This study examines a method for estimating the dermal absorption of benzene contained in hydrocarbon liquids that contact the skin. This method applies to crude oil, gasoline, organic solvents, penetrants, and oils. The flux of benzene through occluded skin as a function of the percent vol/vol benzene in the liquid is derived by fitting a curve to experimental data; the function is supralinear at benzene concentrations benzene is on nonoccluded skin, benzene may preferentially evaporate from the liquid, which thereby decreases the benzene flux. We present a time-averaging method here for estimating the reduced dermal flux during evaporation. Example calculations are presented for benzene at 2% vol/vol in gasoline, and for benzene at 0.1% vol/vol in a less volatile liquid. We also discuss other factors affecting dermal absorption. PMID:22069926

  12. 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)

  13. 27 CFR 21.108 - Ethyl ether.

    Science.gov (United States)

    2010-04-01

    ...Firearms 1 2010-04-01 2010-04-01 false Ethyl ether. 21.108 Section 21.108 Alcohol, Tobacco Products...AND RUM Specifications for Denaturants § 21.108 Ethyl ether. (a) Odor. Characteristic odor. (b) Specific...

  14. 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 irf 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.

  15. Effect of trichloroethylene (TCE) and toluene concentrations on TCE and toluene biodegradation and the population density of TCE and toluene degraders in soil.

    OpenAIRE

    Mu, D. Y.; Scow, K. M.

    1994-01-01

    Toluene is one of several cosubstrates able to support the cometabolism of trichloroethylene (TCE) by soil microbial communities. Indigenous microbial populations in soil degraded TCE in the presence, but not the absence, of toluene after a 60- to 80-h lag period. Initial populations of toluene and TCE degraders ranged from 0.2 x 10(3) to 4 x 10(3) cells per g of soil and increased by more than 4 orders of magnitude after the addition of 20 micrograms of toluene and 1 microgram of TCE per ml ...

  16. 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

  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. Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei

    International Nuclear Information System (INIS)

    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adduon of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased

  19. 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...

  20. 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...

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

    OpenAIRE

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

    2003-01-01

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

  2. 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

  3. Developmental toxicity of prenatal exposure to toluene

    OpenAIRE

    Bowen, Scott E.; Hannigan, John H.

    2006-01-01

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

  4. Mechanistic considerations in benzene physiological model development.

    OpenAIRE

    Medinsky, M. A.; Kenyon, E. M.; Seaton, M. J.; Schlosser, P. M.

    1996-01-01

    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 synergis...

  5. 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.

  6. Human response to varying concentrations of toluene

    DEFF Research Database (Denmark)

    Bælum, Jesper; Lundqvist, G R

    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, increased irritation in the nose and the lower airways, feeling of intoxication, and there were tendencies (P less than 0.1) towards irritation in the throat, headache and dizziness. In the four performance tests there was a tendency towards a lower score in a vigilance test while no effect of toluene exposure was seen in a peg board test, a five choice serial reaction test, or a colour test, indicating only minimal if any effect on the psychomotor or visual performance. There was no difference in the acute effects caused by the exposure containing peak concentrations and by the constant exposure.

  7. Novel Pathway of Toluene Catabolism in the Trichloroethylene-Degrading Bacterium G4

    OpenAIRE

    Shields, Malcolm S.; Montgomery, Stacy O.; Chapman, Peter J.; Cuskey, Stephen M.; Pritchard, P. H.

    1989-01-01

    o-Cresol and 3-methylcatechol were identified as successive transitory intermediates of toluene catabolism by the trichloroethylene-degrading bacterium G4. The absence of a toluene dihydrodiol intermediate or toluene dioxygenase and toluene dihydrodiol dehydrogenase activities suggested that G4 catabolizes toluene by a unique pathway. Formation of a hybrid species of 18O- and 16O-labeled 3-methylcatechol from toluene in an atmosphere of 18O2 and 16O2 established that G4 catabolizes toluene by...

  8. Ethyl 3-carboxy-5-nitrobenzoate

    Directory of Open Access Journals (Sweden)

    Yong-Jun He

    2009-05-01

    Full Text Available In the title compound, C10H9NO6, the carboxy, ethoxycarbonyl and nitro groups form dihedral angles of 3.8?(1, 4.5?(1 and 164.8?(1°, respectively, with the mean plane of the benzene ring. In the crystal structure, molecules lying about inversion centers are linked through O—H...O hydrogen bonds. C—H...O interactions are also present.

  9. [Effect of thermal enhanced soil vapor extraction on benzene removal in different soil textures].

    Science.gov (United States)

    Li, Peng; Liao, Xiao-Yong; Yan, Xiu-Lan; Cui, Xiao-Yong; Ma, Dong

    2014-10-01

    Experiments were carried out to investigate the effect of thermal enhanced soil vapor extraction (SVE) on benzene removal from sand, loam and clay and the mechanism. Compared to the routine control treatment, the benzene removal rates were improved by 13. 1% and 12. 3% and the remediation periods were reduced by 75% and 14%, from sand and loam respectively using thermal enhanced SVE. Thermal enhancement decreased the moisture content and increased the soil permeability of clay. On the surface of clay particles, absorption peaks of carboxyl and ethyl disappeared and the content of soil organic substances decreased significantly. Compared to the conventional SVE, the benzene removal rate was improved by 34% in clay soil treated by thermal enhanced SVE. For sand and loam, thermal enhancement could increase the removal rate by promoting the diffusion of benzene in the soil and achieve substantial removal of pollutants in a relatively short period of time. For clay, it could enhance the effect of SVE by reducing the absorption capacity between soil particle surface and contaminant and improving the performance of the gas diffusion in soil by decreasing the moisture content and increasing the soil permeability. PMID:25693398

  10. MEASUREMENT OF BENZENE OXIDE IN THE BLOOD OF RATS FOLLOWING ADMINISTRATION OF BENZENE

    Science.gov (United States)

    Although it is generally assumed that metabolism of benzene proceeds through an initial step involving oxidation to benzene oxide (BO) by CYP450 in the liver, the production of BO has never been unambiguously confirmed in animals dosed with benzene. Furthermore, prevailing hypo...

  11. 3-Ethyl-4-[(E-2-methylbenzylideneamino]-1H-1,2,4-triazole-5(4H-thione

    Directory of Open Access Journals (Sweden)

    Shan-Heng Wang

    2008-08-01

    Full Text Available Crystals of the title compound, C12H14N4S, were obtained from a condensation reaction of 4-amino-3-ethyl-1H-1,2,4-triazole-5(4H-thione and 2-methylbenzaldehyde. In the molecular structure, there is a short N=C double bond [1.255?(2?Å], and the benzene and triazole rings are located on opposite sites of this double bond. The two rings are approximately parallel to each other, the dihedral angle being 1.75?(11°. A partially overlapped arrangement is observed between the nearly parallel triazole and benzene rings of adjacent molecules; the perpendicular distance of the centroid of the triazole ring from the benzene ring is 3.482?Å, indicating the existence of ?–? stacking in the crystal structure.

  12. The fate of benzene-oxide.

    Science.gov (United States)

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

    2010-03-19

    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 alpha,beta-unsaturated aldehyde, trans-trans-muconaldehyde (MCA). Further reduction or oxidation of MCA gives rise to either 6-hydroxy-trans-trans-2,4-hexadienal or 6-hydroxy-trans-trans-2,4-hexadienoic acid. Both MCA and the hexadienal metabolite are myelotoxic in animal models. Alternatively, benzene-oxide can undergo conjugation with glutathione (GSH), resulting in the eventual formation and urinary excretion of S-phenylmercapturic acid. Benzene-oxide is also a substrate for epoxide hydrolase, which catalyzes the formation of benzene dihydrodiol, itself a substrate for dihydrodiol dehydrogenase, producing catechol. Finally, benzene-oxide spontaneously rearranges to phenol, which subsequently undergoes either conjugation (glucuronic acid or sulfate) or oxidation. The latter reaction, catalyzed by cytochromes P450, gives rise to hydroquinone (HQ) and 1,2,4-benzene triol. Co-administration of phenol and HQ reproduces the myelotoxic effects of benzene in animal models. The two diphenolic metabolites of benzene, catechol and HQ undergo further oxidation to the corresponding ortho-(1,2-), or para-(1,4-)benzoquinones (BQ), respectively. Trapping of 1,4-BQ with GSH gives rise to a variety of HQ-GSH conjugates, several of which are hematotoxic when administered to rats. Thus, benzene-oxide gives rise to a cascade of metabolites that exhibit biological reactivity, and that provide a plausible metabolic basis for benzene-mediated myelotoxicity. Benzene-oxide itself is remarkably stable, and certainly capable of translocating from its primary site of formation in the liver to the bone marrow. However, therein lies the challenge, for although there exists a plethora of information on the metabolism of benzene, and the fate of benzene-oxide, there is a paucity of data on the presence, concentration, and persistence of benzene metabolites in bone marrow. The major metabolites in bone marrow of mice exposed to 50 ppm [(3)H]benzene are muconic acid, and glucuronide and/or sulfate conjugates of phenol, HQ, and catechol. Studies with [(14)C/(13)C]benzene revealed the presence in bone marrow of protein adducts of benzene-oxide, 1,4-BQ, and 1,4-BQ, the relative abundance of which was both dose and species dependent. In particular, histones are bone marrow targets of [(14)C]benzene, although the identity of the reactive metabolite(s) giving rise to these adducts remain unknown. Finally, hematotoxic HQ-GSH conjugates are present in the bone marrow of rats receiving the HQ/phenol combination. In summary, although the fate of benzene-oxide is known in remarkable detail, coupling this information to the site, and mechanism of action, remains to be established. PMID:20036650

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

    International Nuclear Information System (INIS)

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

  14. Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

    OpenAIRE

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

  16. Structure of ethyl phenyl selenone.

    Science.gov (United States)

    Hoier, H; Carrell, H L; Glusker, J P; Spears, C P

    1993-03-15

    C8H10O2Se, M(r) = 217.13, monoclinic, P2(1)/n, a = 9.511 (2), b = 15.741 (3) c = 11.467 (2) A, beta = 91.31 (2) degrees, V = 1716.3 (6) A3, Z = 8 (two molecules per asymmetric unit), Dx = 1.68 Mg m-3, lambda (Mo K alpha) = 0.71069 A, mu = 4.19 mm-1, F(000) = 864, T congruent to 295 K, R(obs) = 0.060 for 1944 unique reflections with I > 2 sigma (I). The two molecules in the asymmetric unit are very similar; they differ only in the conformation of the ethyl side chain. There is considerable disorder in one molecule, that possibly can be represented by torsion about the Se-C(ethyl) bond. In each case the O atoms of the SeO2 group lie near the plane of the phenyl group. Se-O ... H-C interactions appear to be the only significant intermolecular interactions. These involve an H atom of the alpha-C atom of the ethyl group in addition to the H atoms of the phenyl group. PMID:8484923

  17. Toluene mediated oxidative stress and granulo-monocytopoiesis

    OpenAIRE

    Boži? Tatjana P.; Z?, Stevanovic? Jelka; Kova?evi? Milica M.; Jovi? Slavoljub Z.; Luki? Sanja; Petakov Marijana D.; Borozan Sun?ica Z.; Mija?evi? Zora M.; Kneževi? Milijana A.; Bulaji? Snežana B.

    2003-01-01

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

  18. Antipyrine clearance during experimental and occupational exposure to toluene.

    OpenAIRE

    Døssing, M.; Baelum, J.; 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 u...

  19. Somatosensory evoked potentials in workers exposed to toluene and styrene.

    OpenAIRE

    St?tkárová, I; Urban, P; Procházka, B; Lukás, E

    1993-01-01

    Somatosensory evoked potentials (SEPs) were used to evaluate possible subclinical impairment of the nervous system due to occupational exposure to toluene and styrene. A group of 36 rotogravure printers with severe exposure to toluene, 20 workers with severe exposure to styrene in a glass laminate manufacturing plant, and a comparison group of healthy subjects were studied. The severity of exposure was documented by measurements of toluene and styrene concentrations in breathing zone air, by ...

  20. Novel strategies for imaging temperature distribution using Toluene LIF

    International Nuclear Information System (INIS)

    The distinct temperature dependence of toluene fluorescence has enabled the application of toluene laser-induced fluorescence (LIF) for quantitative imaging of temperature. Two novel thermometry techniques based on toluene LIF are introduced and demonstrated: a single-color detection method, which can be applied for temperature measurements in homogeneously seeded flows and a two-color detection technique (i.e. the simultaneous detection of two different wavelength regions of the fluorescence spectrum) that can be applied in inhomogeneously seeded systems

  1. Anaerobic degradation of toluene by a denitrifying bacterium.

    OpenAIRE

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

    1991-01-01

    A denitrifying bacterium, designated strain T1, that grew with toluene as the sole source of carbon under anaerobic conditions was isolated. The type of agar used in solid media and the toxicity of toluene were determinative factors in the successful isolation of strain T1. Greater than 50% of the toluene carbon was oxidized to CO2, and 29% was assimilated into biomass. The oxidation of toluene to CO2 was stoichiometrically coupled to nitrate reduction and denitrification. Strain T1 was toler...

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

    International Nuclear Information System (INIS)

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

  3. 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.

  4. 1-Butyl-3-ethyl-1H-benzimidazol-3-ium tetrafluoroborate

    Directory of Open Access Journals (Sweden)

    Denise M. Junge

    2012-10-01

    Full Text Available In the title salt, C13H19N2+·BF4?, an ionic liquid, the butyl and ethyl substituents bonded to the N atoms of the imidazole ring [r.m.s. deviation = 0.019?(1?Å] adopt equatorial positions. The crystal structure exhibits slipped ?–? interactions between the imidazole and benzene rings of neighbouring molecules [centroid–centroid distance = 3.529?(2?Å]. In the tetrafluoroborate anion, the B and F atoms are disordered over two sets of sites with site-occupancy factors of 0.813?(7 and 0.187?(7.

  5. 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; 0.3ppm) 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

  6. Epoxidation of cyclohexene by ethyl benzene hydroperoxide in the presence of molybdenum catalyst

    International Nuclear Information System (INIS)

    The change in the catalytic activity of Mo(CO)6 in the course of epoxydation of olephins (cyclohexene) by ethylbenzene hydroperoxide in an ethylbenzene solution was investigated. It is shown that the latent period is due to the transition of Mo(CO)6 to an active form corresponding to the complex Mo(CO)6-Mo(CO)sub(6-(n+1))Olsub(n)ROOH, where Ol is an olephin molecule and n=1 or 2

  7. Epoxidation of cyclohexene by ethyl-benzene hydroperoxide in the presence of molybdenum catalyst

    International Nuclear Information System (INIS)

    A study has been made of the kinetic experimental pattern and mechanism of epoxidation of cyclohexene by ethylbenzene hydroperoxide during catalysis by Mo(CO)6 in various solvents. A first order of reaction with respect to the catalyst and complex order of reaction with respect to the hydroperoxide and olefine have been established. Simple (square and cross) inhibition by reaction products, cyclohexene oxide and methylphenylcarbinol, have been found. An increase in the dielectric constant of the solvent diminishes the epoxidation rate. The mechanism scheme of the process is proposed and main kinetic parameters calculated

  8. Epoxidation of cyclohexene by ethyl-benzene hydroperoxide in the presence of molybdenum catalyst

    International Nuclear Information System (INIS)

    A study has been made of catalytic activity of molybdenum hexacarbonyl derivatives in the process of epoxidation of cyclohexene by ethylbenzene peroxide in an ethylbenzene solution. The effect of the degree of substitution of the CO group and nature of a non-carbonyl ligand has been investigated. The reaction has been found to have the first order with respect to the catalyst for all the carbonyl complexes studied. A new method has been proposed for preparation of the catalytic system active in epoxidation using ultraviolet irradiation of Mo(CO)6 solutions

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

    OpenAIRE

    Cimi A Daniel; S. Sugunan

    2013-01-01

    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...

  10. Tricarbonylbis(tricyclohexylphosphine-?Pruthenium(0 toluene solvate

    Directory of Open Access Journals (Sweden)

    Andreas Nader

    2008-11-01

    Full Text Available The title compound, [Ru(C18H33P2(CO3]·C7H8, shows a distorted trigonal-bipyramdial coordination around the central Ru atom, with the two phosphine ligands occupying the axial positions. Two toluene molecules per asymmetric unit with site-occupation factors of 0.5 are observed. One of them forces two of the CO ligands to enclose a wider C—Ru—C bond angle [127.5?(3°] than in the solvent-free crystal structure of [Ru(PCy32(CO3] (Cy is cyclohexyl.

  11. Structure and hardness of ethyl halides and ethyl tosylate

    International Nuclear Information System (INIS)

    Structures of EtX (X = F, Cl, Br, I, OTs) are ab initio (RHF) optimized by using of different basis sets. Total charges on atoms of EtX are determined. It is found that Mulliken and NPA analysis can not give the proper electron density distribution in the molecules of the compounds studied. Topological analysis for the calculated EtX in the framework of Bader's theory of atoms in molecule are performed. The global hardness and the relative local hardness of the ethylating agents studied were estimated

  12. Effects of Relative Humidity on Ozone and Secondary Organic Aerosol Formation from the Photooxidation of Benzene and Ethylbenzene

    Science.gov (United States)

    Jia, L.; Xu, Y.

    2012-12-01

    The formation of ozone and secondary organic aerosol from benzene-NOx and ethylbenzene-NOx irradiations was investigated under different levels of relative humidity (RH) in a smog chamber. The results show that the increase in RH can greatly reduce the maximum O3 by the transformation of -NO2 and -ONO2-containing products into the particle phase. In benzene irradiations, the SOA number concentration increases over 26 times as RH rises from ethylbenzene irradiations, ethylglyoxal favors the formation of monohydrate, which limits the RH effects. During evaporating processes, the lost substances have similar structures for both benzene and ethylbenzene. This demonstrates that ethyl-containing substances are very stable and difficult to evaporate. For benzene some of glyoxal hydrates are left to form C-O-C and C=O-containing species like hemiacetal and acetal after evaporation, whereas for ethylbenzene, glyoxal favors cross reactions with ethylglyoxal during the evaporating process. It is concluded that the increase in RH can irreversibly enhance the yields of SOA from both benzene and ethylbenzene.

  13. Toxicokinetics of toluene and urinary excretion of hippuric acid after human exposure to 2H8-toluene.

    OpenAIRE

    Löf, A; Wigaeus Hjelm, E; Colmsjö, A; Lundmark, B O; Norström, A; Sato, A

    1993-01-01

    Nine male volunteers were exposed to 2H8-toluene (200 mg/m3 for two hours during a workload of 50 W) via inspiratory air with the aid of a breathing valve and mouthpiece. Labelled toluene was used to differentiate between hippuric acid originating from exposure to toluene and hippuric acid normally excreted in urine. The total uptake of toluene was 2.2 (standard deviation (SD) 0.2) mmol, or 50% of the amount inhaled. Four hours after the end of exposure 1.4 (SD 0.3) mmol or 65% of the total u...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-30

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

  15. 75 FR 52768 - Withdrawal of Approval of New Animal Drug Applications; Dichlorophene and Toluene Capsules

    Science.gov (United States)

    2010-08-27

    ...Drug Applications; Dichlorophene and Toluene Capsules AGENCY: Food and Drug Administration...NADAs) for use of dichlorophene and toluene deworming capsules for cats and dogs...101-497 for TINY TIGER (dichlorophene/toluene) Worming Capsules, NADA 101-498...

  16. Studies of the Cataluminescence of Benzene Homologues onNanosized γ–Al2O3/Eu2O3 and the Development of a Gas Sensorfor Benzene Homologue Vapors

    Directory of Open Access Journals (Sweden)

    Cuiqin Wu

    2006-12-01

    Full Text Available The cataluminescence (CTL of benzene and the benzene homologues tolueneand xylene on nanosized γ–Al2O3 doped with Eu2O3 (γ–Al2O3/Eu2O3 was studied and asensor of determining these gases was designed. The proposed sensor showed highsensitivity and selectivity at an optimal temperature of 432 ºC, a wavelength of 425 nm anda flow rate of 400 mL/min. Quantitative analysis was performed at the optimal conditions.The linear ranges of CTL intensity versus concentration of the benzene homologues were asfollows: benzene 2.4~5000 mL/m3, toluene 4.0~5000 mL/m3 and xylene 6.8~5000 mL/m3,with detection limits (3σ of 1.8 mL/m3, 3.0 mL/m3 and 3.4 mL/m3 for each one,respectively. The response time of this system was less than 3 s. The coexistence of othergases, such as SO2, CO and NH3, caused interference at levels around 11.7%, 5.8% and8.9% respectively. The technique is a convenient and fast way of determining the vapors ofbenzene homologues in air.

  17. Morpholine-4-carboxamidinium ethyl carbonate

    OpenAIRE

    Ioannis Tiritiris

    2012-01-01

    The asymmetric unit of the title salt, C5H12N3O+·C3H5O3?, contains two carboxamidinium and two ethyl carbonate ions. In the crystal, the C—N bond lengths in the central CN3 units of the cations range between 1.324?(2) and 1.352?(2)?Å, indicating partial double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charges are delocalized in the...

  18. BEHAVIOR OF TOLUENE ADDED TO SLUDGE-AMENDED SOILS

    Science.gov (United States)

    Toluene is a priority pollutant that can be introduced to soils in a variety of wastes, including some municipal sludges. aboratory experiments were conducted to study the behavior of toluene in two soils in the presence and absence of municipal sludge. ludge additions increased ...

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

    OpenAIRE

    Isken, S.; Bont, J. A.

    1996-01-01

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

  20. Four Bacillus sp. soil isolates capable of degrading phenol, toluene, biphenyl, naphthalene and other aromatic compounds exhibit different aromatic catabolic potentials

    OpenAIRE

    ?oki? Lidija; Naran?i? Tanja; Nikodinovi?-Runi? Jasmina; Bajki? Sanja; Vasiljevi? Branka

    2011-01-01

    Two novel Bacillus sp. were isolated from a soil sample from a bank of the Tamiš river in close proximity to a petrochemical facility. They were capable of utilizing a broad range of aromatic compounds as a sole source of carbon and energy (including phenol, benzene, toluene, biphenyl, naphthalene). The isolates were designated as Bacillus sp. TN41 and TN42, based on their 16S rDNA sequence. Their catabolic potential was compared to two Bacillus sp. strains (PS1 and PS11) isolated from...

  1. Identification of a Novel Dioxygenase Involved in Metabolism of o-Xylene, Toluene, and Ethylbenzene by Rhodococcus sp. Strain DK17

    OpenAIRE

    Kim, Dockyu; Chae, Jong-Chan; Zylstra, Gerben J.; Kim, Young-Soo; Kim, Seong-Ki; Nam, Myung Hee; Kim, Young Min; Kim, Eungbin

    2004-01-01

    Rhodococcus sp. strain DK17 is able to grow on o-xylene, benzene, toluene, and ethylbenzene. DK17 harbors at least two megaplasmids, and the genes encoding the initial steps in alkylbenzene metabolism are present on the 330-kb pDK2. The genes encoding alkylbenzene degradation were cloned in a cosmid clone and sequenced completely to reveal 35 open reading frames (ORFs). Among the ORFs, we identified two nearly exact copies (one base difference) of genes encoding large and small subunits of an...

  2. The inorganic analogues of carbo-benzene

    Science.gov (United States)

    Jalife, Said; Audiffred, Martha; Islas, Rafael; Escalante, Sigfrido; Pan, Sudip; Chattaraj, Pratim K.; Merino, Gabriel

    2014-08-01

    Inspired by carbo-benzene, we have analyzed in silico the stability of carbo-borazine (C12B3N3H6) and the iminobora-mer of borazine (B9N9H6). Both systems may be regarded as the inorganic analogues of carbo-benzene, being B9N9H6 the perfect case. Unlike aromatic carbo-benzene, C12B3N3H6 and B9N9H6 can be classified as almost nonaromatic systems as indicated by the computed induced magnetic field. All these systems undergo dimerization very readily; therefore, they cannot be synthesized as such. However, akin to substituted carbo-benzene, the substitution of the hydrogen atom of C12B3N3H6 and B9N9H6 by other groups could stabilize them.

  3. Adsorption of toluene and toluene–water vapor mixture on almond shell based activated carbons

    OpenAIRE

    Martínez de Yuso, A.; Izquierdo Pantoja, María Teresa; Rubio Villa, Begoña; Carrot, P. J. M.

    2013-01-01

    The aim of work is to study the adsorption of a common volatile organic compound such as toluene using activated carbons prepared by chemical activation with phosphoric acid of a lignocellulosic precursor, almond shell, under different conditions. The Impregnation ratio, temperature and time of activation were modified to obtain activated carbons with different characteristics. Regarding the characteristics of the activated carbons, the effects of porous structure and surface chemistry on the...

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

    Czech Academy of Sciences Publication Activity Database

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

    2012-01-01

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

  5. The effect of toluene on oxidative processes in rat blood

    Directory of Open Access Journals (Sweden)

    SILVANA S. STAJKOVIC

    2009-01-01

    Full Text Available This study was designed to investigate the effects of toluene treatment on oxidative stress in rat blood. Since toluene metabolism produces reactive oxygen and nitrogen species, it was hypothesized that the toluene treatment would: 1 provoke changes in the activities of antioxidant enzymes, 2 impair the integrity of the cell membrane and 3 induce structural changes in the plasma proteins. Female Wistar rats were treated with toluene intraperitonally, at a daily dose of 0.38 mmol/kg body weight for 12 days, and 5 mmol/kg body weight for 6 days, respectively, with propylene glycol as the carrier. Toluene significantly increased superoxide dismutase activity at low doses, catalase activity at high doses and the level of erythrocytes malondialdehyde in both treated groups when compared to the control group. The nitrite (NO2- level in both treated groups was not different from that in the control animals. Toluene caused oxidative modification of plasma proteins and, consequently, changes in the concentration of glycoproteins and lipoproteins when compared to the control group. The observed alterations indicate that toluene treatment might be involved in free radical processes.

  6. Development of a hybrid fermentation-enzymatic bioprocess for the production of ethyl lactate from dairy waste.

    Science.gov (United States)

    Koutinas, Michalis; Menelaou, Maria; Nicolaou, Evrydiki N

    2014-08-01

    This work explores the potential for the development of a hybrid fermentation-enzymatic process for the production of ethyl lactate from dairy waste. Cheese whey was used in Kluyveromyces marxianus and Lactobacillus bulgaricus batch cultures to produce ethanol and lactic acid respectively. Subsequently, the fermentation products were transferred into an organic phase through liquid-liquid extraction and ethyl lactate was formed in an esterification reaction catalyzed by lipases. The production of ethanol and lactic acid achieved under different conditions was 23gL(-1) and 29gL(-1), respectively. Furthermore, the efficiency of various organic solvents for the esterification reaction was evaluated and toluene was chosen for application in the process. The effect of water content was determined aiming to maximize the product yield and 40mgml(-1) was the optimal enzyme concentration. The bioprocess achieved maximum conversion of 33% constituting a valuable alternative to the application of energy demanding chemically derived methods. PMID:24785788

  7. Linking Toluene Degradation with Specific Microbial Populations in Soil

    OpenAIRE

    Hanson, Jessica R.; Macalady, Jennifer L.; Harris,David; Scow, Kate M.

    1999-01-01

    Phospholipid fatty acid (PLFA) analysis of a soil microbial community was coupled with 13C isotope tracer analysis to measure the community’s response to addition of 35 ?g of [13C]toluene ml of soil solution?1. After 119 h of incubation with toluene, 96% of the incorporated 13C was detected in only 16 of the total 59 PLFAs (27%) extracted from the soil. Of the total 13C-enriched PLFAs, 85% were identical to the PLFAs contained in a toluene-metabolizing bacterium isolated from the same so...

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

    OpenAIRE

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

    1990-01-01

    A cohort of 1020 rotogravure printers exposed to toluene and employed for a minimum period of three months in eight plants during 1925-85 was studied. Air levels of toluene were available since 1943 in one plant and since 1969 in most. Based on these measurements and on present concentrations of toluene in blood and subcutaneous fat, the yearly average air levels in each plant were estimated. They reached a maximum of about 450 ppm in the 1940s and 1950s but were only about 30 ppm by the mid-...

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

    Science.gov (United States)

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

    2014-11-26

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

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

    Directory of Open Access Journals (Sweden)

    Moritz Schubert

    2014-09-01

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

  11. 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

  12. Environmental effect of rapeseed oil ethyl ester

    International Nuclear Information System (INIS)

    Exhaust emission tests were conducted on rapeseed oil methyl ester (RME), rapeseed oil ethyl ester (REE) and fossil diesel fuel as well as on their mixtures. Results showed that when considering emissions of nitrogen oxides (NOx), carbon monoxide (CO) and smoke density, rapeseed oil ethyl ester had less negative effect on the environment in comparison with that of rapeseed oil methyl ester. When fuelled with rapeseed oil ethyl ester, the emissions of NOx showed an increase of 8.3% over those of fossil diesel fuel. When operated on 25-50% bio-ester mixed with fossil diesel fuel, NOx emissions marginally decreased. When fuelled with pure rapeseed oil ethyl ester, HC emissions decreased by 53%, CO emissions by 7.2% and smoke density 72.6% when compared with emissions when fossil diesel fuel was used. Carbon dioxide (CO2) emissions, which cause greenhouse effect, decreased by 782.87 g/kWh when rapeseed oil ethyl ester was used and by 782.26 g/kWh when rapeseed oil methyl ester was used instead of fossil diesel fuel. Rapeseed oil ethyl ester was more rapidly biodegradable in aqua environment when compared with rapeseed oil methyl ester and especially with fossil diesel fuel. During a standard 21 day period, 97.7% of rapeseed oil methyl ester, 98% of rapeseed oil ethyl ester and only 61.3% of fossil diesel fuel were biologically decomposed. (author)

  13. Benzene monitoring at CPPI service stations

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Beller, H. R.; Reinhard, M.; Grbic?-galic?, D.

    1992-01-01

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

  15. Effects of ethanol and phenobarbital treatments on the pharmacokinetics of toluene in rats.

    OpenAIRE

    Wang, R. S.; Nakajima, T.

    1992-01-01

    Rats were exposed to toluene at a wide range of concentrations from 50 to 4000 ppm for six hours, and the effects of ethanol and phenobarbital (PB) treatments on the pharmacokinetics of toluene metabolism were investigated. Ethanol treatment influenced toluene metabolism mainly at low exposure concentrations. Thus ethanol accelerated the clearance of toluene from blood only when the blood concentration of toluene was not high (less than 360 microM), and ethanol increased hippuric acid (HA) ex...

  16. Benzylsuccinate Formation as a Means of Anaerobic Toluene Activation by Sulfate-Reducing Strain PRTOL1

    OpenAIRE

    Beller, H. R.; Spormann, A. M.

    1997-01-01

    Permeabilized cells of toluene-mineralizing, sulfate-reducing strain PRTOL1 catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. Recent in vitro studies with two toluene-mineralizing, denitrifying bacteria demonstrated the same fumarate addition reaction and indicated that it may be the first step of anaerobic toluene degradation. This study with strain PRTOL1 shows that anaerobic toluene activation by fumarate addition occurs in bacteria as dispar...

  17. Hepatic metabolism of toluene after gastrointestinal uptake in humans

    DEFF Research Database (Denmark)

    Bælum, Jesper; MØlhave, Lars

    1993-01-01

    The metabolism of toluene and the influence of small doses of ethanol were measured in eight male volunteers after gastrointestinal uptake, the toluene concentration in alveolar air and the urinary excretion of hippuric acid and ortho-cresol being used as the measures of metabolism. During toluene exposure to 2 mg.min-1 for 3 h the alveolar toluene concentration was 0.07 (range 0-0.11) mg.m-3; exposure to 6 mg.min-1 for 30 min increased the alveolar concentration to 0.9 (range 0.03-2.6) mg.m-3. Ingestion of 0.08, 0.16, and 0.32 g of ethanol per kilogram of body weight during toluene exposure of 2 mg.min-1 increased the alveolar concentration within 10 min, and maximal alveolar concentrations of 5 (SD 3), 24 (SD 11), and 39 (SD 28) mg.m-3 were reached after 30, 60, and 90 min for the three doses, respectively. Hippuric acid excretion was only decreased by an ethanol dose of 0.32 g.kg-1. Very low doses of ethanol inhibit toluene metabolism, and the procedure is sensitive enough to measure metabolic interactionsbetween solvents and other xenobiotics in humans.

  18. Semicontinuous microcosm study of aerobic cometabolism of trichloroethylene using toluene

    International Nuclear Information System (INIS)

    A semicontinuous slurry-microcosm method was applied to mimic trichloroethylene (TCE) cometabolic biodegradation field results at the Que-Jen in-situ pilot study. The microcosm study confirmed the process of aerobic cometabolism of TCE using toluene as the primary substrate. Based on the nucleotide sequence of 16S rRNA genes, the toluene-oxidizing bacteria in microcosms were identified, i.e. Ralstonia sp. P-10 and Pseudomonasputida. The first-order constant of TCE-degradation rate was 0.5 day-1 for both Ralstonia sp. P-10 and P.putida. The TCE cometabolic-biodegradation efficiency measured from the slurry microcosms was 46%, which appeared pessimistic compared to over 90% observed from the in-situ pilot study. The difference in the TCE cometabolic-biodegradation efficiency was likely due to the reactor configurations and the effective time duration of toluene presence in laboratory microcosms (1 days) versus in-situ pilot study (3 days). The results of microcosm experiments using different toluene-injection schedules supported the hypothesis. With a given amount of toluene injection, it is recommended to maximize the effective time duration of toluene presence in reactor design for TCE cometabolic degradation

  19. The cyanogen-ethyl ethers of glycerin

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2008-01-01

    Pseudomonas putida S12 is well known for its remarkable solvent tolerance. Transcriptomics analysis of this bacterium grown in toluene-containing chemostats revealed the differential expression of 253 genes. As expected, the genes encoding one of the major solvent tolerance mechanisms, the solvent efflux pump SrpABC and its regulatory genes srpRS were heavily up-regulated. The increased energy demand brought about by toluene stress was also reflected in transcriptional changes: genes involved...

  1. Toluene-4-monooxygenase, a three-component enzyme system that catalyzes the oxidation of toluene to p-cresol in Pseudomonas mendocina KR1.

    OpenAIRE

    Whited, G. M.; Gibson, D. T.

    1991-01-01

    Pseudomonas mendocina KR1 grows on toluene as a sole carbon and energy source. A multicomponent oxygenase was partially purified from toluene-grown cells and separated into three protein components. The reconstituted enzyme system, in the presence of NADH and Fe2+, oxidized toluene to p-cresol as the first detectable product. Experiments with p-deutero-toluene led to the isolation of p-cresol which retained 68% of the deuterium initially present in the parent molecule. When the reconstituted ...

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

    Directory of Open Access Journals (Sweden)

    Waseeq Ahmad Siddiqui

    2008-03-01

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

  3. Determination of the unburnt benzene in the autovehicular emission

    International Nuclear Information System (INIS)

    The exhaust benzene emission from passengers cars has been characterized using a methodology based on deuterated compounds. European vehicles were fueled with a gasoline containing a total benzene concentration (hydrogenated plus deuterated) ranging from 0.98 to 2.75 v/v. Since deuterated benzene at the tail pipe can be present only as unburnt from the fuel, calculating the relative ratio of hydro/deutero compound, the unreacted benzene and that formed in the combustion process can be recognized and the corresponding percentage of unburnt compound qualified. This approach allowed to confirm the benzene formation in the catalytic converter. The experimental data, both for a vehicle equipped with a three way catalytic muffler and for a carburetor car, fit the expected curve describing the percentage of emitted unburnt benzene (considered with respect to the total amount of benzene in the exhaust gas) vs. the benzene content of the gasoline

  4. 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 ...

  5. Hydrogen Absorption at Room Temperature in Nanoscale Titanium Benzene Complexes

    OpenAIRE

    Phillips, A. B.; Shivaram, B. S.

    2009-01-01

    In this letter we report the first room temperature gravimetric measurements of hydrogen absorption in nanoscale titanium-benzene complexes formed by laser ablation in a benzene atmosphere in a UHV chamber. We are able to obtain a 6% by weight absorption as predicted by recent density functional theory based calculations under the conditions of low benzene pressure (35 milli-torr) and for sub-monolayer samples. For samples synthesized under higher benzene pressures we find a...

  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. Dual responsive pickering emulsion stabilized by poly[2-(dimethylamino)ethyl methacrylate] grafted cellulose nanocrystals.

    Science.gov (United States)

    Tang, Juntao; Lee, Micky Fu Xiang; Zhang, Wei; Zhao, Boxin; Berry, Richard M; Tam, Kam C

    2014-08-11

    A weak polyelectrolyte, poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA), was grafted onto the surface of cellulose nanocrystals via free radical polymerization. The resultant suspension of PDMAEMA-grafted-cellulose nanocrystals (PDMAEMA-g-CNC) possessed pH-responsive properties. The grafting was confirmed by FTIR, potentiometric titration, elementary analysis, and thermogravimetric analysis (TGA); the surface and interfacial properties of the modified particles were characterized by surface tensiometer. Compared to pristine cellulose nanocrystals, modified CNC significantly reduced the surface and interfacial tensions. Stable heptane-in-water and toluene-in-water emulsions were prepared with PDMAEMA-g-CNC. Various factors, such as polarity of solvents, concentration of particles, electrolytes, and pH, on the properties of the emulsions were investigated. Using Nile Red as a florescence probe, the stability of the emulsions as a function of pH and temperature was elucidated. It was deduced that PDMAEMA chains promoted the stability of emulsion droplets and their chain conformation varied with pH and temperature to trigger the emulsification and demulsification of oil droplets. Interestingly, for heptane system, the macroscopic colors varied depending on the pH condition, while the color of the toluene system remained the same. Reversible emulsion systems that responded to pH were observed and a thermoresponsive Pickering emulsion system was demonstrated. PMID:24983405

  8. 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.

  9. 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.

  10. 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: 2.423, year: 2013

  11. Comparative Study on the EC50 Value in Single and Mixtures of Dimethylformamide, Methyl Ethyl Ketone, and Toluene.

    Science.gov (United States)

    Kim, Ki-Woong; Won, Yong Lim; Park, Dong Jin; Kim, Doh-Hee; Song, Kwan Young

    2014-09-01

    The aim of this research was to improve our understanding of human toxicity due to exposure to DMF, MEK, or TOL individually as compared to exposure to DMF-MEK or DMF-TOL mixtures, by comparing EC50 values as well as the morphological changes in HepG2 cells treated with these substances. We found that there was marked cell necrosis in the groups treated with mixtures than in those treated with the compounds alone, and that the amount of cell death and the EC50 value were more dependent on MEK and TOL than on DMF. Moreover, analysis of the changes in effective concentration curves revealed that MEK had an antagonistic effect on the human toxicity of DMF, whereas TOL had a synergistic effect. Accordingly, these results suggest that in workplaces involved in the manufacture of synthetic leather, mixtures of DMF and TOL should be avoided as much as possible in order to minimize environmental toxicity and protect the health of the workers. PMID:25343014

  12. Comparative Study on the EC50 Value in Single and Mixtures of Dimethylformamide, Methyl Ethyl Ketone, and Toluene

    OpenAIRE

    Kim, Ki-Woong; Won, Yong Lim; Park, Dong Jin; Kim, Doh-Hee; Song, Kwan Young

    2014-01-01

    The aim of this research was to improve our understanding of human toxicity due to exposure to DMF, MEK, or TOL individually as compared to exposure to DMF-MEK or DMF-TOL mixtures, by comparing EC50 values as well as the morphological changes in HepG2 cells treated with these substances. We found that there was marked cell necrosis in the groups treated with mixtures than in those treated with the compounds alone, and that the amount of cell death and the EC50 value were more dependent on MEK...

  13. 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 reported values for toluene removal in trickling filters. The removal was determined by the gas/liquid mass transfer and the biological degradation as well. An analytical model described the toluene removal as a half-order removal by use of two sets of parameters for the gas/liquid mass transfer and the biological degradation due to the two different gas flows. The mass transfer coefficients and the surface removal rates estimated by parameter fitting corresponded to previously observed values. The effect of the gas flow on the mass transfer coefficient and the biological removal rate may be explained by different flow patterns of the gas and the liquid phases. A characterisation of the biofilm showed an almost even biofilm growth over the filter height, which was in accordance with a constant liquid concentration throughout the column. (C) 1997 IAWQ. Published by Elsevier Science Ltd.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Nuria Vidal

    2012-12-01

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

  16. 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.

  17. The importance of the diluent for airway transport of toluene diisocyanate following intranasal dosing of mice.

    Science.gov (United States)

    Ebino, K; Lemus, R; Karol, M H

    1999-03-01

    Uncertainty of the transport of reactive chemicals to the lung is a major concern when using intranasal dosing of animals. In a preliminary study using mice, intranasal instillation of the dyes methylene blue (in water) and Sudan black B (in 1:4 ethyl acetate:olive oil), indicated that the following conditions were necessary to achieve transport to the lung: (1) aqueous diluent, (2) light anesthesia prior to dosing, (3) holding the animal in a supine position during chemical application, and (4) maintaining the animal in the same position postdosing. Using these conditions, we investigated the distribution of toluene diisocyanate (TDI), a major industrial asthmogen, to the lung following intranasal administration. Female C57BL/6 mice received 20 microl of 1% TDI in ethyl acetate:olive oil (1:4). Group 1 received a single application on day 1; group 2, single applications on 2 consecutive days; group 3, single applications on 4 consecutive days; and group 4, a single application of the vehicle on 2 consecutive days. All mice were necropsied 24 h after the final application. The nasal passages, upper pharynx, trachea, lungs, and olfactory bulbs of each animal were examined with hematoxylin-eosin and immunohistochemical staining, the latter using a rabbit anti-TDI antiserum. Histopathology revealed desquamation of ciliated epithelial cells as well as inflammatory cell debris in the nasal cavity and upper pharynx of animals in groups 1-3. The intensity of these changes was dependent on the number of applications. No inflammation was observed in the trachea, lungs, or olfactory bulbs in any of the groups. Immunohistochemical examination revealed positive staining for the TDI moiety in epithelial cells of the nasal cavity and upper pharynx in animals of groups 1-3. No staining was observed in the trachea, lungs, or olfactory bulbs of any animal. These results suggest that TDI, when dissolved in olive oil:ethyl acetate and applied intranasally, does not reach the trachea and/or lower airways. PMID:10380165

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

    OpenAIRE

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

    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 possibilit...

  19. 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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  2. 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

  3. Synthesis of carbon-14 labelled ethyl chloride

    International Nuclear Information System (INIS)

    A new efficient method of synthesis of ethyl chloride (1,2-14C), based on the Ba14CO3 and dry hydrogen chloride as starting materials has been developed and described. Addition of the hydrogen chloride to ethylene (1,2-14C), obtained from Ba14CO3, has been carried out in the presence of the AlCl3 as catalyst. The outlined method leads to ethyl chloride (1,2-14C) of high specific activity. The radiochemical yield of the reaction based on the activity of barium carbonate used was 72%. (author)

  4. Toluene concentrations in the blood and alveolar air of workers during the workshift and the morning after.

    OpenAIRE

    Brugnone, F.; Rosa, E.; Perbellini, L.; Bartolucci, G. B.

    1986-01-01

    Occupational toluene exposure was studied during the workshift and the morning after by the analysis of environmental air, alveolar air, and blood. Environmental toluene exposure was measured by both continuous and instantaneous sampling. Instantaneous environmental toluene concentrations correlated better with alveolar toluene concentrations (r = 0.94; n = 155) than with blood toluene concentrations (r = 0.71; n = 52). Continuous environmental toluene concentrations correlated better with bl...

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

    Science.gov (United States)

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

  6. 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.

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

    OpenAIRE

    Shunmugavel, Saravanamurugan; Riisager, Anders

    2011-01-01

    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 amoun...

  8. 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.

  9. 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.

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

    OpenAIRE

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

    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.

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

    OpenAIRE

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

    1996-01-01

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

  12. Aerobic and Anaerobic Toluene Degradation by a Newly Isolated Denitrifying Bacterium, Thauera sp. Strain DNT-1

    OpenAIRE

    Shinoda, Yoshifumi; Sakai, Yasuyoshi; Uenishi, Hiroshi; Uchihashi, Yasumitsu; Hiraishi, Akira; Yukawa, Hideaki; Yurimoto, Hiroya; Kato, Nobuo

    2004-01-01

    A newly isolated denitrifying bacterium, Thauera sp. strain DNT-1, grew on toluene as the sole carbon and energy source under both aerobic and anaerobic conditions. When this strain was cultivated under oxygen-limiting conditions with nitrate, first toluene was degraded as oxygen was consumed, while later toluene was degraded as nitrate was reduced. Biochemical observations indicated that initial degradation of toluene occurred through a dioxygenase-mediated pathway and the benzylsuccinate pa...

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

    OpenAIRE

    Ogawa Masanori; Sasahara Teppei

    2012-01-01

    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 bef...

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

    OpenAIRE

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

    1983-01-01

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

  15. Substrate induction and metabolite accumulation during anaerobic toluene utilization by the denitrifying strain T1.

    OpenAIRE

    Frazer, A. C.; Ling, W.; Young, L. Y.

    1993-01-01

    The denitrifying strain T1 utilizes toluene anaerobically. We now report that anaerobic toluene degradation is inducible in strain T1. Fluoracetate treatment of cell suspensions inhibited both the rate of toluene metabolism and the formation of the toluene dead-end products benzylsuccinate and benzylfumarate, which is consistent with the pathway proposed by Evans et al. (Appl. Environ. Microbiol. 58:496-501, 1992). In addition, when either nitrate was limiting or fluoroacetate was added, benz...

  16. Benzene-mediated protein kinase C activation.

    OpenAIRE

    Da Silva, C.; Fan, X. T.; Castagna, M.

    1989-01-01

    Extracellular ligands transfer information into the cell through several pathways that operate in an integrated fashion. Protein kinase C, and enzyme that plays a pivotal role in signal transduction, is the molecular target for tumor promoters from the series of phorbol esters. A number of structurally unrelated tumor promoters also enhance protein kinase C, interacting or not interacting with the phorbol ester binding site. Evidence is provided that benzene potently activate protein kinase C...

  17. DEVELOPMENT OF A SYSTEMATIC APPROACH TO ACCURATELY MEASURE TRACE LEVELS OF VOLATILE ORGANIC COMPOUNDS (VOCS) IN SOIL AND SEDIMENT CONTAINING HIGH MOISTURE TO MEET THE EPA'S RISK ASSESSMENT NEEDS

    Science.gov (United States)

    A majority of the contaminated sites within the United States contain volatile organic compounds (VOCs), either as industrial chlorinated solvents or petroleum products commonly referred to as BTEX (benzene, toluene, ethyl benzene, and xylene). The present EPA methods for low le...

  18. 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)...

  19. 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.

  20. Identification and Expression of Benzylsuccinate Synthase Genes in a Toluene-Degrading Methanogenic Consortium?

    OpenAIRE

    Washer, Cheryl E.; Edwards, Elizabeth A.

    2006-01-01

    Benzylsuccinate synthase (BSS) initiates anaerobic toluene biodegradation, and BSS genes have been found in several nitrate- and iron-reducing organisms. Here, two new putative bssA genes were identified in a methanogenic toluene-degrading culture. Transcription was upregulated with toluene but not with benzoate, consistent with the proposed function. These are the first bss sequences from a methanogenic culture.

  1. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 2010-07-01 false Toluene sulfonamide bis-phe-nol A epoxy adduct...Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct...chemical substance identified generically as toluene sulfonamide bisphenol A epoxy...

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

    Science.gov (United States)

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

  3. Interactions between Asphaltenes and Water in Solutions in Toluene

    DEFF Research Database (Denmark)

    Khvostichenko, Daria; Andersen, Simon Ivar

    2008-01-01

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

  4. Antipyrine clearance during experimental and occupational exposure to toluene

    DEFF Research Database (Denmark)

    DØssing, M; Bælum, Jesper

    1983-01-01

    Exposure to toluene vapour enhances hepatic microsomal enzyme function in animals as assessed by the metabolism of the test drug antipyrine. Thirty six printing trade workers with long term occupational exposure to a mixture of organic solvents and 39 matched controls were randomly allocated into four groups. Eighteen printers and 21 controls were exposed to 100 ppm of toluene during 6.5 hours in an exposure chamber. The remaining 18 printers and 18 controls were exposed to 0 ppm of toluene under similar conditions. The salivary clearance of antipyrine was measured immediately after the stay in the exposure chamber to investigate a possible acute change in liver function and was repeated two weeks later, shortly before the summer vacation. Antipyrine clearance was measured again at the end of the summer vacation-four weeks after exposure. To study a possible effect of chronic exposure on antipyrine clearance 12 printing trade workers with 17 years (median) of occupational exposure to toluene vapour at concentrations of about 100 ppm were investigated before and four weeks after cessation of exposure. No difference in antipyrine clearance was found either within the groups or between the groups at any of the measurements.

  5. Transalkylation of toluene with trimethylbenzenes over large-pore zeolites.

    Czech Academy of Sciences Publication Activity Database

    Krej?í, Andrea; Al-Khattal, S.; Ashraf Ali, M.; Voláková, Martina; ?ejka, Ji?í

    2010-01-01

    Ro?. 377, 1-2 (2010), s. 99-106. ISSN 0926-860X R&D Projects: GA AV ?R 1QS400400560 Institutional research plan: CEZ:AV0Z40400503 Keywords : transalkylation * toluene * zeolites Beta Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.383, year: 2010

  6. Influence of 3d-metal acetylacetonates on toluene ?-radiolysis

    International Nuclear Information System (INIS)

    Formation of toluene radiolysis dimeric products in the presence of cobalt, iron and manganese acetylacetonates is studied. It is shown that Co(AA)2 considerably decreases the yield of benzyl-methyl cyclohexadiene but has no specific influence on dibenzyl yield. Explanation of the observed acetylacetonate influence is presented

  7. Radiation oxidation of the water solution of toluene

    International Nuclear Information System (INIS)

    The radiation oxidation of toluene in water solution saturated with air, N2O and Ar was investigated. Organic hydroperoxide was not detected. H2O2 addition to the system had a great influence on the accumulation rate of dimers and on the hydrogenperoxide itself. This fact indicates that hydrogenperoxide takes part in the reaction. The reaction rate is also discussed. (author)

  8. 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.

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

    International Nuclear Information System (INIS)

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

  10. 46 CFR 151.50-42 - Ethyl ether.

    Science.gov (United States)

    2010-10-01

    ...2010-10-01 2010-10-01 false Ethyl ether. 151.50-42 Section 151.50-42...Requirements § 151.50-42 Ethyl ether. (a)(1) Gravity tanks shall...taken to prevent the contamination of ethyl ether by strong oxidizing agents. (h)...

  11. 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...

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

    OpenAIRE

    R.C. Werlang; A.A. Silva

    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 isola...

  13. Water and polymer dynamics in poly(hydroxyl ethyl acrylate-co-ethyl acrylate) copolymer hydrogels

    OpenAIRE

    Rodríguez Hernández, José Carlos; Gómez Ribelles, José Luís; Monleón Pradas, Manuel; P. Pissis; Kyritsis, A.; Spanoudaki, A.; Pandis, C.; Hartmann, L.; Pelster, R.; Shinyashiki, N; PISSIS, POLYKARPOS

    2011-01-01

    Water and polymer dynamics in hydrogels based on random copolymers of hydrophilic poly( hydroxyl ethyl acrylate) (PHEA) and hydrophobic poly(ethyl acrylate) (PEA), in wide ranges of composition, were investigated by means of two dielectric techniques, thermally stimulated depolarization currents (TSDC) and, mainly, broadband dielectric relaxation spectroscopy (DRS) at several levels of relative humidity/water content. Water sorption of the hydrogels was studied by equilibrium sorption isother...

  14. 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.

  15. Some effects of temperature on fluorescence for pure toluene and liquid scintillator

    International Nuclear Information System (INIS)

    The fluorescence maxima of pure toluene shift to longer wavelengths at lower temperatures. At room temperature the wavelength of the fluorescence maximum of pure toluene is longer than that of hexane. The red shift suggests that the fluorescence emission from excimer of toluene is promoted at lower temperatures. The fluorescence intensity from pure toluene and PPO solution in toluene increases with decreasing temperature. The differential pulse-height distributions from ?- and phenomena are explained by the promoted solvent excimer fluorescence at lower temperatures. (author)

  16. 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...

  17. 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

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

    OpenAIRE

    Smith, Martyn T.; Zhang, Luoping; Mchale, Cliona M.; Skibola, Christine F.; Rappaport, Stephen M.

    2011-01-01

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

  19. Ethyl 3,7-dichloroquinoline-8-carboxylate

    Directory of Open Access Journals (Sweden)

    Fengxia Zhu

    2008-11-01

    Full Text Available The title compound, C12H9Cl2NO2, was prepared by the esterification of 3,7-dichloroquinoline-8-carboxylic acid with triethyl phosphite. The crystal structure is stabilized by aromatic ?–? stacking between the benzene and the pyridine rings of neighbouring molecules [centroid–centroid distances = 3.716?(2 and 3.642?(2?Å]. In addition, weak intermolecular C—H...N hydrogen bonds are present in the structure.

  20. (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.

  1. Effective Liquid-phase Nitration of Benzene Catalyzed by a Stable Solid Acid Catalyst: Silica Supported Cs2.5H0.5PMo12O40

    International Nuclear Information System (INIS)

    Silica supported Cs2.5H0.5PMo12O40 catalyst was prepared through sol-gel method with ethyl silicate-40 as silicon resource and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen adsorption-desorption and potentiometric titration methods. The Cs2.5H0.5PMo12O40 particles with Keggin-type structure well dispersed on the surface of silica, and the catalyst exhibited high surface area and acidity. The catalytic performance of the catalysts for benzene liquid-phase nitration was examined with 65% nitric acid as nitrating agent, and the effects of various parameters were tested, which including temperature, time and amount of catalyst, reactants ratio, especially the recycle of catalyst was emphasized. Benzene was effectively nitrated to mononitro-benzene with high conversion (95%) in optimized conditions. Most importantly, the supported catalyst was proved has excellent stability in the nitration progress, and there were no any other organic solvent and sulfuric acid were used in the reaction system, so the liquid-phase nitration of benzene that we developed was an eco-friendly and attractive alternative for the commercial technology

  2. Clean production of methyl ethyl ketone (MEK)

    International Nuclear Information System (INIS)

    Methyl ethyl ketone oxime (MEKO) was obtained by reaction of methyl ethyl ketone (MEK) with ammonia and hydrogen peroxide using titanium silicalite-1 (TS-1) as catalyst. The effect of reaction temperature, type of solvent, molar ratios of NH3/MEK, H2O2/MEK and mg catalyst/mmol MEK ratio was studied. Water was the most appropriate solvent to obtain high selectivity to oxime. 100% selectivity to MEKO and 60% conversion of MEK was obtained at 70 Celsius degrade using the following parameters: H2O2/MEK = 0,7 and NH3/MEK = 1,12. mg.catalyst/mmol MEK = 10,5. Little decrease in the catalytic activity was observed after reusing the catalysts twice suggesting that incorporated Ti in the MFI structure is rather stable under the studied conditions

  3. Methyl ethyl ketone extraction of Tc species

    International Nuclear Information System (INIS)

    Methyl ethyl ketone extraction of technetium species from aqueous solutions of neutron irradiated ammonium molybdate crystals was studied. The two species extracted were separated by high voltage paper electrophoresis. One of them was the sup(99m)TcOsub(4)sup(-) ion and the other a sup(99m)Tc non-charged immobile species, probably TcOsub(2).aq, which concentrated at the point of application on the electrophoresis paper strip. (author)

  4. Ethyl ester production from (RBD) palm oil

    OpenAIRE

    Oscar Mauricio Martínez Ávila; Francisco José Sánchez Castellanos; Oscar Yesid Suárez Palacios

    2010-01-01

    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 ...

  5. Crystal structure of ethyl 2-amino-4-(4-meth-oxy-phen-yl)-4H-1-benzothieno[3,2-b]pyran-3-carboxyl-ate.

    Science.gov (United States)

    Bakhouch, Mohamed; Kerbal, Abdelali; El Yazidi, Mohamed; Saadi, Mohamed; El Ammari, Lahcen

    2015-05-01

    The mol-ecule of the title compound, C21H19NO4S, features a fused ring system whereby a five-membered ring is flanked by two six-membered rings. This is linked to an ethyl 3-carboxyl-ate group and to a meth-oxy-benzene group. The fused-ring system is quasi-planar, with the greatest deviation from the mean plane being 0.131?(1)?Å for the methine C atom. The plane through the meth-oxy-benzene ring is nearly perpendicular to that through the fused-ring system, as indicated by the dihedral angle of 85.72?(6)°. An intra-molecular N-H?O hydrogen bond is noted. In the crystal, mol-ecules are linked by N-H?O hydrogen bonds, forming layers that stack along the a axis. PMID:25995952

  6. Crystal structure of ethyl 2-amino-4-(4-meth­oxy­phen­yl)-4H-1-benzothieno[3,2-b]pyran-3-carboxyl­ate

    Science.gov (United States)

    Bakhouch, Mohamed; Kerbal, Abdelali; El Yazidi, Mohamed; Saadi, Mohamed; El Ammari, Lahcen

    2015-01-01

    The mol­ecule of the title compound, C21H19NO4S, features a fused ring system whereby a five-membered ring is flanked by two six-membered rings. This is linked to an ethyl 3-carboxyl­ate group and to a meth­oxy­benzene group. The fused-ring system is quasi-planar, with the greatest deviation from the mean plane being 0.131?(1)?Å for the methine C atom. The plane through the meth­oxy­benzene ring is nearly perpendicular to that through the fused-ring system, as indicated by the dihedral angle of 85.72?(6)°. An intra­molecular N—H?O hydrogen bond is noted. In the crystal, mol­ecules are linked by N—H?O hydrogen bonds, forming layers that stack along the a axis. PMID:25995952

  7. (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.

  8. 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.

  9. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Alkyl benzene sulfonic acids and alkyl sulfates, amine salts... § 721.9595 Alkyl benzene sulfonic acids and alkyl sulfates, amine salts...identified generically as alkyl benzene sulfonic acids and alkyl sulfates,...

  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. 76 FR 52875 - 2-Propenoic Acid, Polymer With Ethenylbenzene and (1-methylethenyl) Benzene, Sodium Salt...

    Science.gov (United States)

    2011-08-24

    ...1- methylethenyl) Benzene, Sodium Salt; Tolerance Exemption AGENCY: Environmental...1-methylethenyl) benzene, sodium salt when used as an inert ingredient in a pesticide...1- methylethenyl) benzene, sodium salt on food or feed commodities. DATES:...

  12. 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...

  13. Antibodies to toluene diisocyanate in an environmentally exposed population.

    OpenAIRE

    Orloff, K G; Batts-Osborne, D; Kilgus, T; Metcalf, S; Cooper, M

    1998-01-01

    Residents living near a polyurethane foam manufacturing facility expressed concern to health officials over chemical emissions from the plant. Environmental monitoring of ambient air near the plant indicated the presence of toluene diisocyanate (TDI), which was used in foam production. Health officials collected blood samples from 113 residents and analyzed the blood sera for antibodies to TDI and related diisocyanates. Ten of the 113 residents (9%) had elevated levels of IgG or IgE antibodie...

  14. Persistent reactive airway dysfunction syndrome after exposure to toluene diisocyanate.

    OpenAIRE

    Luo, J C; Nelsen, K G; Fischbein, A

    1990-01-01

    Two police officers developed asthma like illness after a single but prolonged exposure to toluene diisocyanate (TDI) by being in the immediate vicinity of a tank car that had overturned on a highway. One officer experienced upper and lower respiratory tract symptoms with chest tightness about 4.5 hours after initial exposure. Shortness of breath, cough, and wheezing were noted the following day. The other experienced symptoms immediately on exposure, developed shortness of breath 20 minutes ...

  15. Eco friendly nitration of toluene using modified zirconia

    OpenAIRE

    K.R. Sunaja Devi; Jayashree, S

    2013-01-01

    Nitration of toluene has been studied in the liquid phase over a series of modified zirconia catalysts.  Zirconia, zirconia- ceria (Zr0.98Ce0.02)O2, 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 wa...

  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. Reactions of recoiling 11C atoms with toluene

    International Nuclear Information System (INIS)

    Formation of benzocyclobutene, a characteristic rearrangement product of tolylmethylenes, strongly suggests that these species are formed as intermediates in the reactions of recoiling carbon-11 atoms and toluene. Degradation and additive studies indicated that both singlet and triplet carbon atoms can lead to benzocyclobutene formation through insertion into ring C-H bonds. Styrene is also formed, predominantly by insertion of singlet C-11 atoms into a methyl C-H bond, followed by rearrangement of the resulting benzylmethylene

  18. Toluene nitration in irradiated nitric acid and nitrite solutions

    International Nuclear Information System (INIS)

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

  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. N-[4-Acetyl-5-isobutyl-5-(2-p-tolylpropyl-4,5-dihydro-1,3,4-thiadiazol-2-yl]acetamide ethyl acetate hemisolvate

    Directory of Open Access Journals (Sweden)

    Noureddine Mazoir

    2009-01-01

    Full Text Available The racemic title compound, a new terpenoid, C20H29N3O2S·0.5C4H8O2, was synthesized from Cedrus Atlantica essential oil. The compound crystallizes with a disordered ethyl acetate solvent molecule. The thiadiazole ring is almost planar, with a maximum deviation from the mean plane of 0.015?(2?Å for the C atom connected to the isobutyl group and has a puckering amplitude of 0.026?(2?Å. The dihedral angle between the benzene and thiadiazole rings is 18.32?(8°. The crystal packing involves intermolecular N—H...O hydrogen bonds.

  1. (4R-Ethyl 4-(4-chlorophenyl-2-hydroxy-5-oxo-2,3,4,5-tetrahydropyrano[3,2-c]chromene-2-carboxylate

    Directory of Open Access Journals (Sweden)

    Yifeng Wang

    2010-01-01

    Full Text Available The title compound, C21H17ClO6, is optically pure and adopts an R configuration. It was obtained by an organocatalytic asymmetric Michael addition of 4-hydroxycoumarin with (E-ethyl 4-(4-chlorophenyl-2-oxobut-3-enoate. The structure consists of a tetrahydropyran unit fused to the coumarin ring ring system. The hydroxyl and phenyl groups are on the same side of the tetrahydropyrane ring. The benzene ring is almost perpendicular to the coumarin ring [dihedral angle of 72.89?(3°]. In the crystal structure, intermolecular O—H...O hydrogen bonds are observed. An intramolecular O—H...O contact also occurs.

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

    Science.gov (United States)

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

    2015-01-01

    The draft genome of a member of the bacterial family Desulfobulbaceae (phylum Deltaproteobacteria) was assembled from the metagenome of a sulfidogenic [13C6]toluene-degrading enrichment culture. The “Desulfobulbaceae bacterium Tol-SR” genome is distinguished from related, previously sequenced genomes by suites of genes associated with anaerobic toluene metabolism, including bss, bbs, and bam. PMID:25593261

  3. Xenobiotic metabolism and the mechanism(s) of benzene toxicity.

    Science.gov (United States)

    Snyder, Robert

    2004-10-01

    The investigation of the mechanism(s) of benzene toxicity/leukemogenesis over the past 50 years has been contemporaneous with developments in the study of xenobiotic metabolism. Research on the cytochrome P450 (CYP) enzyme system, and related systems in vivo and in vitro, which culminated in the isolation and reconstitution of the many CYPs, established pathways for the study of xenobiotic metabolism and its relationship to the biological activity of many chemicals. The essential role for metabolism of benzene as a precursor to the demonstration of benzene toxicity led to extensive studies of benzene metabolism, many of which will be reviewed here. Benzene toxicity/leukemogenesis, however, is a function of the bone marrow, a site remote from the liver where most benzene metabolism occurs. Studies of benzene metabolism have delineated the array of metabolites which appear to play a role in bone marrow damage, but further studies, both in vivo and in vitro, using appropriate animal models, will be needed to fully understand the impact of benzene and its metabolites on bone marrow function. PMID:15554234

  4. ASPEN HYSYS SIMULATION AND COMPARISON BETWEEN ORGANIC SOLVENTS (SULFOLANE AND DMSO USED FOR BENZENE EXTRACTION

    Directory of Open Access Journals (Sweden)

    T. zaiz

    2013-05-01

    Full Text Available Due to the high increase of the production of aromatic hydrocarbons: benzene, toluene and xylenes BTX from oil because of the large activity of their big markets especially with the availability of great quantities of these aromatic fractions in the oil. This study has two main parts the first presents a general vision of the aromatic hydrocarbons, the second is going to focus on the liquid-liquid extraction with the selected solvents as a separation method. The solvent selection depends on many properties. In this second part there will be a simulation (conception and execution of the liquid-liquid extraction of aromatics by two different organic solvents Sulfolane and DMSO followed by a comparison between the results obtained by the simulation. The simulator used will be ASPEN HYSYS 7.2.The results of the simulation showed that the use DMSO is better than Sulfolane because of the separation efficiency the economic value and the regeneration rate although its use is more dangerous (more toxic than the Sulfolane

  5. Bright-orange organic light emitting diodes fabricated using benzene-naphthalene co-polymer

    International Nuclear Information System (INIS)

    Poly-p-phenylene is a very attractive conducting polymer due to its resemblance with poly-p-phenylene vinylene. Since it is very rigid, intractable and difficult to process, it has not been very popular in the fabrication of organic light emitting diodes (OLEDs). We have co-polymerized benzene and naphthalene using Kovacic's method, which uses the mechanism of propagation of oxidative coupling occurring through a dehydrogenation step via radical cations. The resulting co-polymer is soluble in common organic solvents like toluene and has interesting electrical and optical properties and shows strong photoluminescence. The co-polymer has low melting point and can be purified using vacuum sublimation. The new polymer has an optical absorption band in the visible region of the optical spectrum and a photoluminescence maximum in the orange region. The polymer has been characterized using spectroscopic and thermogravimetric techniques. OLED structure has been fabricated using indium-tin oxide as the bottom electrode, evaporated polymer as the luminescent layer and aluminum as the cathode. The devices give bright electroluminescence on application of approximately 5-V d.c. The photoluminescence of the polymer has also been reported

  6. 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.

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

    OpenAIRE

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

    1988-01-01

    Toluene and m-xylene were rapidly mineralized in an anaerobic laboratory aquifer column operated under continuous-flow conditions with nitrate as an electron acceptor. The oxidation of toluene and m-xylene was coupled with the reduction of nitrate, and mineralization was confirmed by trapping 14CO2 evolved from 14C-ring-labeled substrates. Substrate degradation also took place when nitrous oxide replaced nitrate as an electron acceptor, but decomposition was inhibited in the presence of molec...

  8. Ethyl 5-(4-aminophenylisoxazole-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Jun-Tao Zhao

    2012-04-01

    Full Text Available The asymmetric unit of the title compound, C12H12N2O3, contains two molecules in which the benzene and isoxazole rings are almost coplanar, the dihedral angles between their mean planes being 1.76?(9 and 5.85?(8°. The two molecules interact with each other via N—H...N and N—H...O hydrogen bonds, which link the molecules into layers parallel to the ac plane. The layers stack in a parallel mode with an interlayer distance of 3.36?(7?Å.

  9. 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

  10. Structural, morphological and spectroelectrochemical characterization of poly (2-ethyl aniline)

    OpenAIRE

    Schemid Andreia L.; Co?rdoba, Torresi Susana I.; Bassetto Alessandra N.; Carlos Ivani A.

    2000-01-01

    In this paper a comparative study of the structure, morphology, and the spectroelectrochemical response of poly (2-ethyl aniline) and polyaniline for different counterions is presented. Spongeous structure of poly (2-ethyl aniline) is obtained when mineral acids are used, while homogeneous and compact films are formed using organic acids. The electrochemical response of poly (2-ethyl aniline) depends on the charge/size ratio of the counterion due to both steric and electronic effects. The cor...

  11. 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

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

    Scientific Electronic Library Online (English)

    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 comb [...] inado 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. Abstract in english 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.

  13. Contact dermatitis caused by ethyl alcohol

    Directory of Open Access Journals (Sweden)

    Pasricha J

    1990-01-01

    Full Text Available A 45-year-old lady developed itching and burning sensation in the right cubital fossa, 10 minutes after local application of blue spirit, for withdrawing blood. Erythematous papulo-vesicular lesion appeared in the area after about 8 hours and the dermatitis subsided completely in 5 days with topical fluocinolone acetonide. Two weeks later, she noticed itching and a mild dermatitis on the finger-tips on holding a spirit swab between her fingers. Patch tests resulted in severe papulo-vesicular reactions with blue spirit and absolute ethyl alcohol, but negative reaction with copper sulphate.

  14. Fungal metabolism of toluene: monitoring of fluorinated analogs by (19)F nuclear magnetic resonance spectroscopy

    OpenAIRE

    Prenafeta-boldu, F. X.; Luykx, D. M.; Vervoort, J. J. M.; Bont, J. A. M.

    2001-01-01

    We used isomeric fluorotoluenes as model substrates to study the catabolism of toluene by five deuteromycete fungi and one ascomycete fungus capable of growth on toluene as the sole carbon and energy source, as well as by two fungi (Cunninghamella echinulata and Aspergillus niger) that cometabolize toluene. Whole cells were incubated with 2-, 3-, and 4-fluorotoluene, and metabolites were characterized by 19F nuclear magnetic resonance. Oxidation of fluorotoluene by C. echinulata was initiated...

  15. Fungal Metabolism of Toluene: Monitoring of Fluorinated Analogs by 19F Nuclear Magnetic Resonance Spectroscopy

    OpenAIRE

    Prenafeta-boldu?, Francesc X.; Luykx, Dion M. A. M.; Vervoort, Jacques; Bont, Jan A. M.

    2001-01-01

    We used isomeric fluorotoluenes as model substrates to study the catabolism of toluene by five deuteromycete fungi and one ascomycete fungus capable of growth on toluene as the sole carbon and energy source, as well as by two fungi (Cunninghamella echinulata and Aspergillus niger) that cometabolize toluene. Whole cells were incubated with 2-, 3-, and 4-fluorotoluene, and metabolites were characterized by 19F nuclear magnetic resonance. Oxidation of fluorotoluene by C. echinulata was initiated...

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

    OpenAIRE

    G. Sarwar; K. W. Appel; A. G. Carlton; Mathur, R.; K. Schere; Zhang, R; MAJEED, M.A.

    2010-01-01

    A new condensed toluene mechanism is incorporated into the Community Multiscale Air Quality Modeling system. Model simulations are performed using the CB05 chemical mechanism containing the existing (base) and the new toluene mechanism for the western and eastern US for a summer month. With current estimates of tropospheric emission burden, the new toluene mechanism increases monthly mean daily maximum 8-h ozone by 1.0–3.0 ppbv in Los Angeles, Portland, Seattle, Chicago, Cleveland, northeaste...

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

    OpenAIRE

    Sarwar, G.; Appel, K. W.; Carlton, A. G.; Mathur, R.; Schere, K.; 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, northeas...

  18. Catabolite-mediated mutations in alternate toluene degradative pathways in Pseudomonas putida.

    OpenAIRE

    Leddy, M B; Phipps, D W; Ridgway, H F

    1995-01-01

    Pseudomonas putida 54g grew on mineral salts with toluene and exhibited catechol-2,3-dioxygenase (C23O) activity, indicating a meta pathway. After 10 to 15 days on toluene, nondegrading (Tol-) variants approached nearly 10% of total CFU. Auxotrophs were not detected among variants, suggesting selective loss of catabolic function(s). Variant formation was substrate dependent, since Tol- cells were observed on neither ethylbenzene, glucose, nor peptone-based media nor when toluene catabolism wa...

  19. 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...

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

    OpenAIRE

    Hildebrandt, L.; Donahue, N. M.; Pandis, S. N.

    2009-01-01

    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 co...

  1. Anaerobic degradation of toluene and o-xylene by a methanogenic consortium.

    OpenAIRE

    Edwards, E. A.; Grbic?-galic?, D.

    1994-01-01

    Toluene and o-xylene were completely mineralized to stoichiometric amounts of carbon dioxide, methane, and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was creosote-contaminated sediment from Pensacola, Fla. The adaptation periods before the onset of degradation were long (100 to 120 days for toluene degradation and 200 to 255 days for o-xylene). Successive transfers of the toluene- and o-xylene-degrading cultures remained active. C...

  2. Phenol- and Toluene-Degrading Microbial Populations from an Aquifer in Which Successful Trichloroethene Cometabolism Occurred

    OpenAIRE

    Fries, M. R.; Forney, L. J.; Tiedje, J. M.

    1997-01-01

    We characterized the bacterial populations that grew in a Moffett Field, Calif., aquifer following three sequential field tests of phenol- or toluene-driven cometabolism of trichloroethene (TCE). Reducing the toluene and phenol concentrations in most-probable-number (MPN) tubes from 50 to 5 ppm increased the population density measured for these degraders by 1.5 and 1 log units, respectively, suggesting that natural populations might be quite sensitive to these substrates. Phenol and toluene ...

  3. 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.

  4. Anaerobic Toluene Activation by Benzylsuccinate Synthase in a Highly Enriched Methanogenic Culture

    OpenAIRE

    Beller, Harry R.; Edwards, Elizabeth A.

    2000-01-01

    Permeabilized cells of a highly enriched, toluene-mineralizing, methanogenic culture catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. The specific in vitro rate of benzylsuccinate formation was >85% of the specific in vivo rate of toluene consumption. This is the first report of benzylsuccinate synthase activity in a methanogenic culture; the activity has previously been reported to occur in denitrifying, sulfate-reducing, and anoxygenic photot...

  5. Induction of resistance to X-rays in E. coli by toluene

    International Nuclear Information System (INIS)

    Incubation of unirradiated bacteria with 10 M toluene in buffer for 30 min at 220C did not affect their viability. When E. Coli K12AB1157 were incubated in buffer/toluene (10 M) for 30 min and then X-irradiated under either aerobic or anaerobic conditions in the presence of toluene the derived curves contained large shoulders; the Dsub(q) values were calculated to be 271 Gy and 921 Gy for bacteria irradiated under oxic and anoxic conditions respectively. The final exponential slopes for both curves were less steep than those for the strictly exponential curves obtained for X-irradiated bacteria which had neither been pre-incubated with toluene nor X-irradiated in the presence of toluene. When bacteria were exposed to toluene during the time of X-irradiation only, exponential survival curves were observed with slopes approximately the same as the terminal slopes of the curves for the bacteria pretreated and irradiated in the presence of toluene. When the bacteria were exposed initially to X-rays and then incubated with toluene, the survival curves were identical to those obtained for bacteria untreated with toluene. Survival after U.V. irradiation was the same whether or not the bacteria were treated with toluene before exposure to U.V. The modification of radioresistance by toluene appeared to be independent of the presence of oxygen at the time of irradiation. It is suggested that toluene does not effect the primary fixation of lesions, but may influence ty fixation of lesions, but may influence their subsequent removal. (U.K.)

  6. Reported survival with severe mixed acidosis and hyperlactemia after toluene poisoning

    OpenAIRE

    Omar Amr; Rahman Masood; Abuhasna Said

    2011-01-01

    Lactic acidosis is a recognized complication of the inhalant abuse such as toluene, especially in patients with renal insufficiency. We report a case of severe metabolic acidosis and hyperlactemia due to toluene sniffing. The favorable outcome, despite extremely poor clinical symptoms, signs, laboratory and radiological findings, was unexpected. Specific aspects of the clinical course are addressed. Toluene sniffing should be considered in evaluating sever metabolic acidosis. Favorable outcom...

  7. Enhanced toluene removal using granular activated carbon and a yeast strain Candida tropicalis in bubble-column bioreactors.

    Science.gov (United States)

    Ahmed, Zubair; Hwang, Sun-Jin; Shin, Seung-Kyu; Song, JiHyeon

    2010-04-15

    The yeast strain Candida tropicalis was used for the biodegradation of gaseous toluene. Toluene was effectively treated by a liquid culture of C. tropicalis in a bubble-column bioreactor, and the toluene removal efficiency increased with decreasing gas flow rate. However, toluene mass transfer from the gas-to-liquid phase was a major limitation for the uptake of toluene by C. tropicalis. The toluene removal efficiency was enhanced when granular activated carbon (GAC) was added as a fluidized material. The GAC fluidized bioreactor demonstrated toluene removal efficiencies ranging from 50 to 82% when the inlet toluene loading was varied between 13.1 and 26.9 g/m(3)/h. The yield value of C. tropicalis ranged from 0.11 to 0.21 g-biomass/g-toluene, which was substantially lower than yield values for bacteria reported in the literature. The maximum elimination capacity determined in the GAC fluidized bioreactor was 172 g/m(3)/h at a toluene loading of 291 g/m(3)/h. Transient loading experiments revealed that approximately 50% of the toluene introduced was initially adsorbed onto the GAC during an increased loading period, and then slowly desorbed and became available to the yeast culture. Hence, the fluidized GAC mediated in improving the gas-to-liquid mass transfer of toluene, resulting in a high toluene removal capacity. Consequently, the GAC bubble-column bioreactor using the culture of C. tropicalis can be successfully applied for the removal of gaseous toluene. PMID:20031312

  8. Complete oxidation of toluene under strictly anoxic conditions by a new sulfate-reducing bacterium.

    OpenAIRE

    Rabus, R.; Nordhaus, R; Ludwig, W.; Widdel, F.

    1993-01-01

    A toluene-degrading sulfate-reducing bacterium, strain Tol2, was isolated from marine sediment under strictly anoxic conditions. Toluene was toxic if applied directly to the medium at concentrations higher than 0.5 mM. To provide toluene continuously at a nontoxic concentration, it was supplied in an inert hydrophobic carrier phase. The isolate had oval, sometimes motile cells (1.2 to 1.4 by 1.2 to 2.0 microns). The doubling time was 27 h. Toluene was completely oxidized to CO2, as demonstrat...

  9. 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 lab-scale trickling filter for treatment of toluene-polluted air. The biofilm growth and the activity of P. putida, a representative of the toluene-degrading species in the biofilm which have been described previously (Pedersen et al., 1997) were simulated. The simulation indicated that the volume fraction of the toluene degraders in the biofilm decreased from 12% to only 2% (11% of dry weight) during two weeks. In spite of the low fraction in the biofilm, the toluene degraders supported growth of the dominating part ofnon-toluene-degrading heterotrophs in the biofilm, as toluene was the sole carbon source supplied to the system. The maximum intrinsic growth rate of P. putida in the biofilm was only 20% of the maximum growth rare determined in a batch experiment with suspended P. putida cells. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.

  10. Competition in chemostat culture between Pseudomonas strains that use different pathways for the degradation of toluene.

    OpenAIRE

    Duetz, W. A.; Jong, C.; Williams, P. A.; Andel, J. G.

    1994-01-01

    Pseudomonas putida mt-2, P. cepacia G4, P. mendocina KR1, and P. putida F1 degrade toluene through different pathways. In this study, we compared the competition behaviors of these strains in chemostat culture at a low growth rate (D = 0.05 h-1), with toluene as the sole source of carbon and energy. Either toluene or oxygen was growth limiting. Under toluene-limiting conditions, P. mendocina KR1, in which initial attack is by monooxygenation of the aromatic nucleus at the para position, outco...

  11. 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

  12. Tricarbonylbis(tricyclohexylphosphine-?P)ruthenium(0) toluene solvate

    OpenAIRE

    Andreas Nader; Helmar Görls; Wolfgang Imhof

    2008-01-01

    The title compound, [Ru(C18H33P)2(CO)3]·C7H8, shows a distorted trigonal-bipyramdial coordination around the central Ru atom, with the two phosphine ligands occupying the axial positions. Two toluene molecules per asymmetric unit with site-occupation factors of 0.5 are observed. One of them forces two of the CO ligands to enclose a wider C—Ru—C bond angle [127.5?(3)°] than in the solvent-free crystal structure of [Ru(PCy3)2(CO)3] (Cy is cyclohexyl).

  13. Desorption of toluene from modified clays using supercritical carbon dioxide

    Scientific Electronic Library Online (English)

    D. G. P., Carneiro; M. F., Mendes; G. L. V., Coelho.

    2004-12-01

    Full Text Available The main objective of this work is to study the regeneration capacity of modified clays using supercritical fluid. These modified clays are used as organic compound adsorvents. The experimental step was done using a packed column with the clay contaminated by toluene. The results obtained showed the [...] influence of the density of the supercritical CO2 and of the organic modifier in the desorption process. These data were modeled with first- and second-order models. Better results were obtained using the second-order model. This study makes possible the scale-up of the desorption process for regeneration of solid matrices using supercritical fluids.

  14. 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

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

    OpenAIRE

    Urban, P.; Lukás, E

    1990-01-01

    Visual evoked potentials (VEPs) from stimulation by checkerboard pattern reversal were examined in 54 rotogravure printers exposed to toluene (all men, aged 22-64 years, duration of exposure 1-41 years). A control group consisted of 46 subjects (23 men and 23 women; aged 22-54 years). Compared with controls the exposed group showed more frequent responses with reduced reproducibility or absence of some waves, or both; the mean P1 wave latency was prolonged and mean amplitudes N1P1 and P1N2 we...

  16. Degradation of Toluene and Trichloroethylene by Burkholderia cepacia G4 in Growth-Limited Fed-Batch Culture

    OpenAIRE

    Mars, A. E.; Houwing, J.; Dolfing, J.; Janssen, D. B.

    1996-01-01

    Burkholderia (Pseudomonas) cepacia G4 was cultivated in a fed-batch bioreactor on either toluene or toluene plus trichloroethylene (TCE). The culture was allowed to reach a constant cell density under conditions in which the amount of toluene supplied equals the maintenance energy demand of the culture. Compared with toluene only, the presence of TCE at a toluene/TCE ratio of 2.3 caused a fourfold increase in the specific maintenance requirement for toluene from 22 to 94 nmol mg of cells (dry...

  17. Studies on biological effects induced by chronic ?-irradiation combined with benzene injection in rabbits

    International Nuclear Information System (INIS)

    30 healthy male rabbits, 6-7 months of age, were equally divided into 6 groups. Animals of control and radiation, low benzene and low benzene radiation, high benzene and high benzene radiation groups were injected with 0.6 ml peanut oil, 0.6 ml peanut oil 0.06 ml benzene or 0.6 ml peanut oil + 0.6 ml benzene/d/rabbit, respectively, 5 days per week for 14 weeks. After injection, animals of radiation, low benzene radiation, high benzene radiation groups were irradiated at 0.899 mGy/min. x 60/d. The main results were summarized as follows: (1) The changes of hematopoietic function are close related to the injected dosage of benzene. Damages of hematoietic function in rabbits are enhanced by combined effect of benzene and ?-rays. (2) ?-rays and benzene can induce chromosome aberrations and SCEs. Chromosome aberrations in blood lymphocytes are higher than in marrow cells. Chromosome aberrations induced by ?-rays are higher than SCEs, but no significant linear correlation between the dosage and effects was found. The SCEs of blood lymphocytes induced by benzene are more obvious than chromosome aberrations, Moreover, linear dose effect correlation of acentric in high benzene groups and SCE in high benzene and low benzene radiation groups were observed. The chromosome aberration yield induced by ?-rays can significantly be enhanced by treatment with benzene. The combined cytogenetic effects of radiation with benzene could be synergetic mainly in dicentrics plus rings, beic mainly in dicentrics plus rings, being mainly additive in acentric. SCEs induced by benzene combined with ?-radiation could be enhanced in the low benzene radiation groups. (3) Benzene is a weak mutagen for male reproductive cells, because it can induce more abnormal sperms. Histological damages of tests in rabbits were also enhanced by combined effects of ?-radiation and benzene

  18. 40 CFR 80.1270 - Who may generate benzene credits under the ABT program?

    Science.gov (United States)

    2010-07-01

    ...Early benzene credits. Early benzene credits are credits generated...it owns that has an approved benzene baseline under § 80.1285...of this section must process crude oil and/or intermediate...processing units. (iii) Early benzene credits shall be...

  19. Ethyl 4-(tert-butylamino-3-nitrobenzoate

    Directory of Open Access Journals (Sweden)

    Aisyah Saad Abdul Rahim

    2008-08-01

    Full Text Available In the title compound, C13H18N2O4, intramolecular N—H...O, N—H...N and C—H...O (× 3 hydrogen bonds generate S(6 and S(5 ring motifs. There are two crystallographically independent molecules (A and B in the asymmetric unit. The nitro group is coplanar with the benzene ring, with O—N—C—C torsion angles of ?0.33?(13 and 0.93?(14° in molecules A and B, respectively. In the crystal structure, neighbouring molecules are linked together by intermolecular C—H...O hydrogen bonds. In addition, the crystal structure is stabilized by ?–? interactions with centroid–centroid distances ranging from 3.7853?(6 to 3.8625?(6?Å.

  20. IRIS TOXICOLOGICAL REVIEW OF METHYL ETHYL KETONE (2003 Final)

    Science.gov (United States)

    EPA is announcing the release of the final report, "Toxicological Review of Methyl Ethyl Ketone: in support of the Integrated Risk Information System (IRIS)". The updated Summary for Methyl Ethyl Ketone and accompanying Quickview have also been added to the IRIS Database. ...

  1. 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.

  2. 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

  3. Mechanism of microsomal metabolism of benzene to phenol

    International Nuclear Information System (INIS)

    The mechanism of microsomal hydroxylation of benzene to phenol has been studied by examining the microsomal metabolism of the specifically deuterated derivative 1,3,5-[2H3]benzene. Evidence for the formation of the following four products was obtained: 2,3,5-[2H3]phenol, 3,5-[2H2]phenol, 2,4,6-[2H3]phenol, and 2,4-[2H2]phenol. The presence of 2,3,5-[2H3]phenol and 2,4-[2H2]phenol shows that, in the microsomal metabolism of benzene to phenol, a NIH shift had occurred. A deuterium isotope effect (kH/kD) of approximately 4 was detected in both the meta- and para-deuterated phenols. This finding indicates that cyclohexadienone, formed either by isomerization of the epoxide or directly from the enzyme-substrate complex, is a major intermediate in the metabolism of benzene to phenol

  4. 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.

  5. Soot aging from OH-initiated oxidation of toluene.

    Science.gov (United States)

    Qiu, Chong; Khalizov, Alexei F; Zhang, Renyi

    2012-09-01

    We have conducted laboratory experiments to investigate the impacts of secondary organic aerosol formation on soot properties from OH-initiated oxidation of toluene. Monodisperse soot particles are exposed to the oxidation products of the OH-toluene reaction in an environmental chamber, and variations in particle size, mass, organic mass faction, morphology, effective density, hygroscopicity, and optical properties are simultaneously determined by an integrated aerosol analytical system. The thickness of the organic coating, correlated to reaction time and initial reactant concentrations, is shown to largely govern the particle properties. With the development of organic coating, the soot core is changed from a highly fractal to compact form, evident from the measured effective density and dynamic shape factor. The organic coating increases the particle hygroscopicity, and further exposure of coated soot to elevated relative humidity results in a more spherical particle. The single scattering albedo and scattering and absorption cross sections are also enhanced with the organic coating. Our results suggest that the oxidation products of anthropogenic pollutants alter the composition and properties of soot particles and lead to increased particle density, hygroscopicity, and optical properties, considerably enhancing their impacts on air quality, climate forcing, and human health. PMID:22853850

  6. 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 

  7. Progression of neuropsychological deficits following toluene diisocyanate exposure.

    Science.gov (United States)

    Singer, R; Scott, N E

    1987-01-01

    Three wharf workers were acutely exposed to toluene diisocyanate (TDI) during an accidental chemical spill. Toluene is neurotoxic as a solvent, while cyanates can cause nervous tissue injury or death by hypoxia. Chronic symptoms which occurred following the incident included headache, fatigue, concentration problems, irritability, depression, sleep disturbance, memory and sexual dysfunction. Compared with two months post-exposure, at 16 months post-exposure Full Scale IQ dropped an average of 23 points. Results from additional neuropsychological testing at 16 months post-exposure indicated severe deficits in all three subjects in memory, manual dexterity, visuomotor tracking, mental flexibility, ability to detect figure-ground relationships, and word fluency. Nerve conduction velocity testing indicated abnormal peripheral nervous system function in two of the three workers; however, its etiology is not certain. These results may be relevant to the neurotoxicity of methyl isocyanate exposure, such as occurred in Bhopal, India, where an increasing magnitude of depression, anxiety, fatigue, restlessness, and headaches 18 months post-exposure have been reported. In general, continuing decrement in mental function without concomitant environmental exposure should be considered in neuropsychological assessment of chemical toxicity. PMID:14591141

  8. Backward stimulated Raman scattering in shock-compressed benzene

    International Nuclear Information System (INIS)

    Backward stimulated Raman scattering measurements have been used to measure the frequency shift of the 992-cm-1 vibrational ring-stretching mode of benzene shock-compressed to pressures of 0.6 to 1.2 GPa. Results of the dynamic experiment are compared to shifts measured for benzene isothermally compressed with a diamond-anvil cell. A Grueneisen mode #betta# was determined for this vibrational degree of freedom

  9. Environmental and biological monitoring of benzene during self-service automobile refueling.

    OpenAIRE

    Egeghy, P. P.; Tornero-velez, R.; Rappaport, S. M.

    2000-01-01

    Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (...

  10. 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...

  11. Sub-Doppler Electronic Spectrum of the BENZENE-D2 Complex

    Science.gov (United States)

    Hayashi, Masato; Ohshima, Yasuhiro

    2014-06-01

    Excitation spectrum of the benzene-D2 van der Waals (vdW) complex in the vicinity of the S1 ? S0 601 vibronic transition of the monomer was recorded by utilizing mass-selective two-color resonance-enhanced two-photon ionization. Extensive adiabatic cooling with the rotational temperature of ?rb|sub-Doppler resolution yielding the line width of 250 MHz was realized in a collimated molecular beam by employing Fourier-transform-limited ultraviolet pulses for the excitation. In contrast to our previous study on the benzene-H2 complex, weaker binding ortho nuclear-spin isomer, correlating to the j = 0 state of a freely rotating D2, was observed in addition to the stronger binding para isomer (with j = 1), by using a gas sample of normal D2. Three and two vibronic bands involving vdW-mode excitation were observed for the para and ortho isomers, respectively. By comparing the present results with those of the benzene-H2 complex, we made unambiguous assignments on the vdW modes involved in each observed band, and obtained complete sets of vibrational frequencies of all the three vdW modes for the both H2 and D2 isotopomers in the S1 61 manifold. One of the vdW frequency correlates to the splitting between the m = 0 and ± 1 sublevels in the j = 1 state of a freely rotating H2/D2 molecule, and the potential barrier for the hindered internal rotation has been evaluated to be ca. 60 cm-1 from the values. Ratio of the vdW frequencies between the H2 and D2 species deviate significantly from the value for the harmonic vibration (i.e., ?{2} ? 1.4), indicating substantial anharmonic character of the vdW modes in the complex. M. Hayashi and Y. Ohshima, Chem. Phys. 419, 131-137 (2013). M. Hayashi and Y. Ohshima, J. Phys. Chem. A 117, 9819-9830 (2013).

  12. Kinetics and Mechanism of Pyridinolyses of Ethyl Methyl and Ethyl Propyl Chlorothiophosphates in Acetonitrile

    International Nuclear Information System (INIS)

    The kinetic studies on the reactions of ethyl methyl (2) and ethyl propyl (4) chlorothiophosphates with X-pyridines have been carried out in acetonitrile at 35.0 .deg. C. The free energy correlations with X show biphasic concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of ?X = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of ?X = 0.43(2) and 0.36(4) with weakly basic pyridines are interpreted as a change of the attacking direction of the X-pyridines from a frontside to a backside attack toward the chloride leaving group

  13. (?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.

  14. 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.

  15. 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

  16. Effects of activated carbon fibre-supported metal oxide characteristics on toluene removal.

    Science.gov (United States)

    Liu, Zhen-Shu; Peng, Yu-Hui; Li, Wen-Kai

    2014-01-01

    Few studies have investigated the use of activated carbon fibres (ACFs) impregnated with metal oxides for the catalytic oxidation of volatile organic compounds (VOCs). Thus, the effects of the ACF-supported metal oxides on toluene removal are determined in this study. Three catalysts, namely, Ce, Mn, and Cu, two pretreatment solutions NaOH and H2O2, and three reaction temperatures of 250 degrees C, 300 degrees C, and 350 degrees C, were employed to determine toluene removal. The composition and morphology of the catalysts were analysed using Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometer (FTIR), and thermo-gravimetric analyser (TGA) to study the effects of the catalyst's characteristics on toluene removal. The results demonstrated that the metal catalysts supported on the ACFs could significantly increase toluene removal. The Mn/ACFs and Cu/ACFs were observed to be most active in toluene removal at a reaction temperature of 250 degrees C with 10% oxygen content. Moreover, the data also indicated that toluene removal was slightly improved after pretreating the ACFs with NaOH and H2O2. The results suggested that surface-metal loading and the surface characteristics of the ACFs were the determinant parameters for toluene removal. Furthermore, the removal of toluene over Mn/ACFs-H202 decreased when the reaction temperature considered was > 300 degrees C. PMID:24701949

  17. Abatement of toluene from gas streams via ferro-electric packed bed dielectric barrier discharge plasma

    International Nuclear Information System (INIS)

    Destruction of gaseous toluene via ferro-electric packed bed dielectric barrier discharge plasma in a coaxial cylindrical reactor was carried out at atmospheric pressure and room temperature. The difference among three kinds of reactors was compared in terms of specific energy density (SED), energy yield (EY), toluene decomposition. In order to optimize the geometry of the reactor, the removal efficiency of toluene was compared for various inner electrode diameters. In addition, qualitative analysis on by-products and particular discussion on toluene abatement mechanisms were also presented. It has been found that ferro-electric packed bed DBD reactor could effectively decompose toluene. Toluene removal efficiency enhanced with increasing SED. With respect to toluene conversion, 1.62 mm electrode appeared to be superior to 1.06 mm electrodes. BaTiO3 reactor had the highest toluene removal efficiency among the reactors. For NaNO2 reactor, the highest EY could reach 17.0 mg/kWh to a certain extent.

  18. Toxicity of Trichloroethylene to Pseudomonas putida F1 Is Mediated by Toluene Dioxygenase

    OpenAIRE

    Wackett, Lawrence P.; Householder, Steven R.

    1989-01-01

    Trichloroethylene was metabolically activated by toluene dioxygenase to produce toxic effects in Pseudomonas putida F1. Cytotoxicity was indicated by growth inhibition and by the covalent modification of cellular molecules in P. putida F1 exposed to [14C]trichloroethylene. With a toluene dioxygenase mutant, neither growth inhibition nor alkylation of intracellular molecules was observed.

  19. Collision-induced Energy Transfer and Bond Dissociation in Toluene by H2/D2

    International Nuclear Information System (INIS)

    Energy transfer and bond dissociation of C-Hmethyl and C-Hring in excited toluene in the collision with H2 and D2 have been studied by use of classical trajectory procedures at 300 K. Energy lost by the vibrationally excited toluene to the ground-state H2/D2 is not large, but the amount increases with increasing vibrational excitation from 5000 and 40,000 cm.1. The principal energy transfer pathway is vibration to translation (V-T) in both systems. The vibration to vibration (V-V) step is important in toluene + D2, but plays a minor role in toluene + H2. When the incident molecule is also vibrationally excited, toluene loses energy to D2, whereas it gains energy from H2 instead. The overall extent of energy loss is greater in toluene + D2 than that in toluene + H2. The different efficiency of the energy transfer pathways in two collisions is mainly due to the near-resonant condition between D2 and C-H vibrations. Collision-induced dissociation of C-Hmethyl and C-Hring bonds occurs when highly excited toluene (55,000-70,400 cm-1) interacts with the ground-state H2/D2. Dissociation probabilities are low (10-5?10-2) but increase exponentially with rising vibrational excitation. Intramolecular energy flow between the excited C-H bonds occurring on a subpicosecond timescale is responsible for the bond dissociation

  20. EVALUATING THE NMDA-GLUTAMATE RECEPTOR AS A SITE OF ACTION FOR TOLUENE, IN VIVO

    Science.gov (United States)

    In vitro, toluene disrupts the function of NMDA-glutamate receptors, indicating that effects on NMDA receptor function may contribute to toluene neurotoxicity. NMDA-glutamate receptors are widely present in the visual system and contribute to pattern-elicited visual evoked potent...

  1. DETERMINATION OF SECONDARY ORGANIC AEROSOL PRODUCTS FROM THE PHOTOOXIDATION OF TOLUENE AND THEIR IMPLICATIONS IN AMBIENT PM2.5

    Science.gov (United States)

    Laboratory study was carried out to investigate the secondary organic aerosol products from photooxidation of the aromatic hydrocarbon toluene. The laboratory experiments consisted of irradiating toluene/propylene/NOX/air mixtures in a smog chamber operated in the dynamic mode...

  2. 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.

  3. 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.

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

    OpenAIRE

    Chan, Ming-huan; Chung, Shiang-sheng; Stoker, Astrid K.; Markou, Athina; Chen, Hwei-hsien

    2012-01-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-d-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperat...

  5. Characterization of an inhaled toluene drug discrimination in mice: effect of exposure conditions and route of administration

    OpenAIRE

    Shelton, Keith L.; Slavova-hernandez, Galina

    2009-01-01

    The drug discrimination procedure in animals has been extensively utilized to model the abuse related, subjective effects of drugs in humans, but it has seldom been used to examine abused volatile inhalants like toluene. The present study sought to characterize the temporal aspects of toluene's discriminative stimulus as well assess toluene blood concentrations under identical exposure conditions. B6SJLF1/J mice were trained to discriminate 10 min of exposure to 6000 ppm inhaled toluene vapor...

  6. 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 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

  7. Recruitment and expression of toluene/trichloroethylene biodegradation genes in bacteria native to deep-subsurface sediments.

    OpenAIRE

    Romine, M. F.; Brockman, F. J.

    1996-01-01

    Four plasmids, each encoding a combination of either an Escherichia coli or Pseudomonas putida promoter and either toluene dioxygenase or toluene monooxygenase, were electroporated into five bacterial strains isolated from sediments found at depths of 91 to 295 m. Four of these engineered bacterial strains demonstrated both toluene and trichloroethylene degradation activities.

  8. Perspectives for the biotechnological production of ethyl acetate by yeasts.

    Science.gov (United States)

    Löser, Christian; Urit, Thanet; Bley, Thomas

    2014-06-01

    Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester. PMID:24788328

  9. Ethyl 8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Yoshinobu Ishikawa

    2014-06-01

    Full Text Available In the title compound, C13H13NO4, the asymmetric unit contains four independent molecules, each exhibiting an intramolecular N—H...O hydrogen bond. The ethyl group in one of the four molecules is disordered, with a refined occupancy ratio of 0.295?(16:0.705?(16. A face-to-face stacking interaction is found between the benzene rings of the quinoline units of two of the molecules [centroid–centroid distance = 3.541?(2?Å], which are sandwiched by the other two molecules through N—H...O hydrogen bonding. In the crystal, the sandwiched molecules are assembled via stacking interactions along the b-axis direction with their translation-symmetry equivalents [centroid–centroid distance = 3.529?(2?Å], and are further linked through N—H...O hydrogen bonding. The other two molecules are linked via stacking interactions with their inversion-symmetry equivalents [centroid–centroid distances = 3.512?(3 and 3.716?(4?Å] and via N—H...O hydrogen bonding.

  10. Low level occupational benzene exposure and hematological parameters.

    Science.gov (United States)

    Swaen, Gerard M H; van Amelsvoort, Ludovic; Twisk, Johannes J; Verstraeten, Etienne; Slootweg, Ronald; Collins, James J; Burns, Carol J

    2010-03-19

    At high and prolonged exposure levels (e.g. >30 ppm), benzene can cause hematological effects. However, there is conflicting evidence on potential hematological effects at lower concentrations. We conducted a study to examine hematological effects at low benzene exposure levels in an occupational setting. Extensive exposure data and data from routine hematology examinations were available for Dow employees at the Terneuzen site in the Netherlands. We compared 8532 blood samples of Dow employees with low benzene exposure to 12,173 samples of employees with no benzene exposure that were available for the period between 1981 and 2007. Based on 21,584 benzene air measurements, a Job Exposure Matrix (JEM) was constructed for all employees with exposure. The JEM was used to estimate benzene exposure in the year in which each blood sample was collected. The average lymphocyte counts for the exposed and non-exposed group were similar. By means of mixed model regression adjustments were made for smoking, age and month of blood sample. These adjustments did not change the results and there was no indication for an adverse effect on any of the hematological parameters under investigation. A further stratification of the exposed population into three subgroups (1 ppm) showed no significant differences for any of the hematological parameters between the three exposure categories or compared with the non-exposed group. The analysis modeling the continuous exposure effect relationship showed similar findings. This study does not indicate that workers exposed to low benzene concentrations are at an increased risk for hematological effects. PMID:20074561

  11. 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.

  12. 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.

  13. Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,

    Directory of Open Access Journals (Sweden)

    Mathew Obichukwu EDOGA

    2006-07-01

    Full Text Available First, phenol - formaldehyde (PF and urea - formaldehyde (UFII resins were separately conventionally prepared in our laboratory. Also, UF resin synthesized from the acid modified synthesis procedure was synthesized in a purely acid medium of pH 1.0, FU molar ratio of 1.0 and at 50oC (one-stage acid modified-synthesis procedure. Subsequently, the UF resin II was modified during synthesis by incorporating ethylated urea-ether (EUER (i.e. UFIII and glycerol (GLYC (i.e. UFV cured with and without acid curing agent. The structural and physicochemical analyses of the various resin samples were carried out.The results showed that the unmodified UF resin (UF II synthesized in acid medium of pH 1.0, F/U molar ratio 1.0, and at 50oC, cured in absence of acid curing catalyst, showed features in their spectra which are consistent with a tri-, and/or tetra-substituted urea in the reaction to give a 3 - dimensional network cured UF resin. Modification of the UF resin(UF II with ethylated urea-ether and glycerol to produce UF resins III and respectively V prominently increased the absorbance of methylene and ether groups in the spectra which are consistent with increased hydrophobicity and improved hydrolytic stability. For the conventional UF resin (UF I, the only clear distinction between spectra for the UF resin II and UF resins (III/V is the presence of diminished peaks for methylene groups at 2.2 ppm. The relationship between the logarithmic viscosity of cured PF resin with time showed continuos dependence of viscosity with time during cure up to 70 minutes. Similar trends were shown by UF resins (III/V, cured in absence of acid catalyst. In contrast, the conventional UF resins I and UF IV (i.e. UF II cured with NH4CL showed abrupt discontinuity in viscosity with time just after about 20 minutes of cure.

  14. Switching from photochemical to photothermal mechanism in laser ablation of benzene solutions

    Science.gov (United States)

    Hatanaka, Koji; Kawao, Mitsushi; Tsuboi, Yasuyuki; Fukumura, Hiroshi; Masuhara, Hiroshi

    1997-12-01

    Nanosecond KrF excimer laser ablation of benzyl chloride, benzyl alcohol, toluene, ethylbenzene, and n-propylbenzene diluted in n-hexane, n-heptane, dichloromethane, and 1,2-dichloroethane was investigated by time-resolved photographic, photoacoustic, and absorbance measurements. Ablation threshold values, Fth, for high concentration solutions (?=250 cm-1, 0.6-1 M) were confirmed to be correlated to photochemical reactivity (?-bond cleavage) of the solute molecules, whereas no distinct relation between Fth and boiling point of solvents was observed. Time-resolved absorbance at the laser wavelength was almost constant during the excitation pulse, which means that the main light-absorbing molecules were fixed to the ground-state solutes. It is considered that this type of ablation is initiated by the photochemical fragmentation. On the contrary, Fth observed in relatively low concentration solutions (?=25 cm-1, 0.06-0.1 M) were about twice higher than those for the high concentration solutions, and had no direct correlation with the photochemical reactivity of the solute molecules. The time-resolved absorbance increased during the excitation pulse, and was ascribed to the fact that benzyl radicals produced by the photodissociation of solute molecules absorbed the excitation photons and converted them into heat through "a cyclic multiphotonic absorption process." Furthermore, morphological aspects observed in nanosecond photography exhibited appreciable differences by varying the solute concentrations. These results clearly mean a concentration-dependent ablation mechanism; the ablation mechanism of the benzene derivative solutions switches from photochemical to photothermal as the solute concentration decreases.

  15. 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.

  16. 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.

  17. Analysis of residual toluene in food packaging via headspace extraction method using gas chromatography

    International Nuclear Information System (INIS)

    Polymeric materials are used in many food contact applications as packaging material. The presence of residual toluene in this food packaging material can migrate into food and thus affect the quality of food. In this study, a manual headspace analysis was successfully designed and developed. The determination of residual toluene was carried out with standard addition method and multiple headspace extraction, MHE) method using gas chromatography-flame ionization detector, GC-FID). Identification of toluene was performed by comparison of its retention time with standard toluene and GC-MS. It was found that the suitable heating temperature was 180 degree Celsius with an optimum heating time of 10 minutes. The study also found that the concentration of residual toluene in multicolored sample was higher compared to mono colored sample whereas residual toluene in sample analyzed using standard addition method was higher compared to MHE method. However, comparison with the results obtained from De Paris laboratory, France found that MHE method gave higher accuracy for sample with low analyte concentration. On the other hand, lower accuracy was obtained for sample with high concentration of residual toluene due to systematic errors. Comparison between determination methods showed that MHE method is more precise compared to standard addition method. (author)

  18. Complete oxidation of toluene under strictly anoxic conditions by a new sulfate-reducing bacterium.

    Science.gov (United States)

    Rabus, R; Nordhaus, R; Ludwig, W; Widdel, F

    1993-05-01

    A toluene-degrading sulfate-reducing bacterium, strain Tol2, was isolated from marine sediment under strictly anoxic conditions. Toluene was toxic if applied directly to the medium at concentrations higher than 0.5 mM. To provide toluene continuously at a nontoxic concentration, it was supplied in an inert hydrophobic carrier phase. The isolate had oval, sometimes motile cells (1.2 to 1.4 by 1.2 to 2.0 microns). The doubling time was 27 h. Toluene was completely oxidized to CO2, as demonstrated by measurement of the degradation balance. The presence of carbon monoxide dehydrogenase and formate dehydrogenase indicated a terminal oxidation of acetyl coenzyme A via the CO dehydrogenase pathway. The use of hypothetical intermediates of toluene degradation was tested in growth experiments and adaptation studies with dense cell suspensions. Results do not support a degradation of toluene via one of the cresols or methylbenzoates, benzyl alcohol, or phenylacetate as free intermediate. Benzyl alcohol did not serve as growth substrate; moreover, it was a strong, specific inhibitor of toluene degradation, whereas benzoate utilization was not affected by benzyl alcohol. Sequencing of 16S rRNA revealed a relationship to the metabolically dissimilar genus Desulfobacter and on a deeper level to the genus Desulfobacterium. The new genus and species Desulfobacula toluolica is proposed. PMID:7686000

  19. 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.

  20. 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 studyd in the study

  1. 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.

  2. Complete Toluene Oxidation on Pt/CeO2-ZrO2-ZnO Catalysts

    OpenAIRE

    Nobuhito Imanaka; Toshiyuki Masui; Tomoya Kamata; Min Yeong Kim

    2013-01-01

    A 0.4 wt%Pt/Ce0.76Zr0.19Zn0.05O1.95 catalyst was prepared by the evaporative drying method. The catalytic toluene oxidation activity of the catalyst was investigated and the calcination temperature dependence on the toluene oxidation activity was characterized. It was confirmed that only CO2 and steam were produced by the complete oxidation of toluene, and no toluene-derived compounds were detected as by-products with a gas chromatography-mass spectrometer. Toluene was completely oxidized at ...

  3. 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, ...

  4. Toluene toxicokinetics and metabolism parameters in the rat and guinea pig.

    Science.gov (United States)

    Campo, P; Blachère, V; Payan, J P; Cossec, B; Ducos, P

    2006-05-01

    Cochlear disruptions induced by toluene were shown in the rat but not in the guinea pig. To better understand the differences between species, three investigations were carried out to study (1) the blood affinity and the pulmonary uptake of the solvent, (2) its clearance and (3) its urinary elimination in both species. The blood affinity of toluene was +44% higher in the rat than in the guinea pig (14.4?g/g versus 10?g/g). Similarly, the pulmonary uptake of toluene was approximately 46.5% more efficient in the rat than in the guinea pig (75.4?g/g versus 40.3?g/g) after 3h inhalation of 1500ppm toluene. Therefore, the physicochemical composition of the blood could explain the difference in the uptake performances between rats and guinea pigs. The clearance of the toluene showed that 10min after an intravenous administration of 400?L of vehicle containing 28?L (43mgkg(-1)) of toluene, the solvent concentration was approximately threefold higher in the rat than in the guinea pig blood. The last experiment was carried out to compare the concentrations of the urinary metabolites. The concentrations of o-cresol, hippuric and benzyl mercapturic acids measured in the urines were different before and after the toluene injection. These data give evidence for large differences of toluene uptake and metabolism between rat and guinea pig. Therefore, it seems reasonable to claim that guinea pigs cochleas are not susceptible to toluene as the blood burden of solvent does not reach the concentration required to induce permanent damages. PMID:21783669

  5. Biodegradation of petrochemical industry compounds by cytochrome P450-producing toluene-degrading bacterium

    Directory of Open Access Journals (Sweden)

    Seyed Mahdi Ghasemi

    2012-01-01

    Full Text Available Introduction: Owing to the serious environmental problems which have occurred due to the increasing amount of toxic petroleum hydrocarbons in the environment, bioremediation of these compounds by microorganisms seems to be necessary. Among these, toluene is a common pollutant in petrochemical industry and a serious cause for concern due to its adverse health effects and carcinogenic potential. Materials and methods: In this study, to isolate toluene-degrading bacteria, contaminated seawater and wastewater samples were collected from the Caspian Sea, the Persian Gulf and municipal wastewater. The best toluene-degrading bacterial strain was biochemically and molecularly characterized and its 16S rDNA sequence was submitted as Bacterium Ex-DG74 (accession no. HQ414235 in NCBI. Then, toluene removal rate, cytochrome P450 enzymatic activity, and growth rate of the isolate on oil and petrochemical contaminants were determined.Results: After enrichment procedures in toluene-containing medium, about twenty toluene-degrading bacteria were isolated. Among them, a newly isolated strain from wastewater exhibited great ability to utilize toluene as the sole source of carbon and energy. According to the results obtained by spectrophotometer and gas chromatograph, Bacterium Ex-DG74 showed a significant tolerance to organic solvent as it could grow in the medium containing %25 (v/v toluene and also degraded over 70 of %1 (v/v toluene as the sole source of carbon and energy. Moreover, this bacterium could grow on different toxic oil and petrochemical compounds.Discussion and conclusion: The results of the present study indicated that cytochrome P450 enzymatic activity can have essential role on biodegradation of different pollutants by Bacterium Ex-DG74. Thus, we suggest this bacterium as a potential biological agent for in situ bioremediation of hydrocarbon-polluted environments.

  6. 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.

  7. 77 FR 12740 - Trinexapac-ethyl; Pesticide Tolerances

    Science.gov (United States)

    2012-03-02

    ...inhalation) Classification: ``Not likely...Exposure Evaluation Model (DEEM\\TM...from drinking water. The Agency...water exposure models in the dietary...trinexapac-ethyl in drinking water. These simulation models take into...

  8. 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...

  9. Experimental exposure to toluene: further consideration of cresol formation in man.

    OpenAIRE

    Woiwode, W; Drysch, K

    1981-01-01

    In two separate experiments 10 healthy men each were exposed at rest in an exposure chamber to about 200 ppm toluene in the air. Hippuric acid, o-, m-, p-cresol, and phenol in urine were detected by capillary gas chromatography at the beginning and at the end of exposure, and at variable times after the cessation of exposure. In addition toluene in blood was determined at the same intervals. The results indicate that in addition to hippuric acid, o-, m-, p-cresol are metabolites of toluene; t...

  10. Role of ionic processes in the formation of free radicals in ?-irradiated glassy toluene

    International Nuclear Information System (INIS)

    Spectrophotometric study has been made on the reaction intermediates generated by ?-irradiation in glassy toluene at 77 K. Benzyl and methylcyclohexadienyl radicals are generated roughly in equal amounts, and the total yield (G value) of the radicals is 0.19. The addition of biphenyl results in the formation of biphenyl anion and cation and depletes the radical yield by 40%. The results indicate that the excited-state toluene, the precursor of the radicals, is generated by recombination of ions as well as by the direct effect of the radiation on toluene

  11. Kinetic and mechanistic analysis of toluene ammoxidation to benzonitrile on vanadium-titanium oxides

    International Nuclear Information System (INIS)

    The kinetics of toluene ammoxidation to benzonitrile on a vanadium-titanium oxide (V-Ti-O) catalyst were studied, using a tubular-flow, stacked-pellet reactor. The reactions of benzonitrile and carbon dioxide formation exhibit approximately first-order with respect to the hydrocarbon partial pressure. The rates are independent of oxygen concentration when this exceeds the stoichiometric amount. An inhibition effect of ammonia on the overall toluene conversion has been observed. A Langmuir-Hinshelwood model has been proposed to represent the experimental data; it considers a competition between toluene and ammonia for the same kind of active sites

  12. 2-cyano-5-(?-(trans-4-alkylcyclohexyl)ethyl)pyridines

    International Nuclear Information System (INIS)

    2-Methyl-5-((4-alkyl-1-hydroxycyclohexyl)ethynyl)pyridines were obtained by the reaction of the organomagnesium derivative of 2-metyl-5-ethynylpyridine with 4-alkylcyclohexanones. The hydrogenation of the products gave 2-methyl-5-((4alkyl-1-hydroxycyclohexyl)ethyl)pyridines, the dehydration of which and subsequent hydrogenation led to 2-methyl-5-((4-alkylcyclohexy)ethyl)pyridines; the methyl group was substituted by a nitrile group according to the usual scheme

  13. Ethyl-substituted erythromycin derivatives produced by directed metabolic engineering

    OpenAIRE

    Stassi, D. L.; Kakavas, S. J.; Reynolds, K. A.; Gunawardana, G.; Swanson, S.; Zeidner, D.; Jackson, M.; Liu, H.; Buko, A.; Katz, L.

    1998-01-01

    A previously unknown chemical structure, 6-desmethyl-6-ethylerythromycin A (6-ethylErA), was produced through directed genetic manipulation of the erythromycin (Er)-producing organism Saccharopolyspora erythraea. In an attempt to replace the methyl side chain at the C-6 position of the Er polyketide backbone with an ethyl moiety, the methylmalonate-specific acyltransferase (AT) domain of the Er polyketide synthase was replaced with an ethylmalonate-specific AT domain from the polyketide synth...

  14. Synthesis of new n-ethyl dehydroamino acid derivatives : n-ethyl ?,?-dibromo, n-ethyl ?-bromo ?-substituted, n-ethyl ?,?-disubstituted n-protected dehydroamino acid methyl esters

    OpenAIRE

    Monteiro, Luís S.; Andrade, Juliana J.; Suárez, Ana C.

    2011-01-01

    Recently we reported the use of a sequence of alkylation and dehydration methodologies to obtain from the methyl esters of N-(4-nitrophenylsulfonyl)-?-hydroxyamino acids, new non-proteinogenic amino acids, namely, N-ethyl-?,?-dehydroamino acids. Thus, it was possible to obtain for the first time, non-natural amino acids which incorporate both the N-ethyl and ?,?-dehydro moieties. Herein, we report the application of this N-alkylation procedure to several methyl esters of ?,?-dibromo an...

  15. 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.

  16. Crystal structure of (E)-N-{2-[2-(4-methyl-benzyl-idene)hydrazin-1-yl]-2-oxoeth-yl}-p-toluene-sulfonamide.

    Science.gov (United States)

    Purandara, H; Foro, Sabine; Gowda, B Thimme

    2015-06-01

    The title acyl-hydrazone derivative, C17H19N3O3S, containing an amino acid moiety and electron-donating substituents attached to both the phenyl rings, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. The mol-ecules are bent at the S atom, with C-SO2-NH-CH2 torsion angles of -67.3?(2) and 67.7?(3)° in mol-ecules A and B, respectively. Further, the dihedral angles between the sulfonyl-glycine segments and the p-toluene-sulfonyl rings are 76.1?(1) and 85.8?(1)° in mol-ecules A and B, respectively. The central hydrazone segments and the toluene rings attached to them are almost co-planar with their mean planes being inclined to one another by 5.2?(2) (mol-ecule A) and 2.9?(2)° (mol-ecule B). The dihedral angles between the benzene rings are 86.83?(12) (mol-ecule A) and 74.00?(14)° (mol-ecule B). In the crystal, the A mol-ecules are linked by a pair of N-H?O hydrogen bonds, forming inversion dimers with an R 2 (2)(8) ring motif. The dimers are linked via three N-H?O hydrogen bonds involving the B mol-ecules, forming chains along [100] and enclosing R 2 (2)(12) and R 4 (4)(16) ring motifs. The chains are linked via C-H?O hydrogen bonds and a C-H?? inter-action, forming sheets parallel to (010). There is a further C-H?? inter-action and a slipped parallel ?-? inter-action [inter-centroid distance = 3.8773?(16)?Å] between the sheets, leading to the formation of a three-dimensional framework. PMID:26090163

  17. Crystal structure of (E)-N-{2-[2-(4-methyl­benzyl­idene)hydrazin-1-yl]-2-oxoeth­yl}-p-toluene­sulfonamide

    Science.gov (United States)

    Purandara, H.; Foro, Sabine; Gowda, B. Thimme

    2015-01-01

    The title acyl­hydrazone derivative, C17H19N3O3S, containing an amino acid moiety and electron-donating substituents attached to both the phenyl rings, crystallized with two independent mol­ecules (A and B) in the asymmetric unit. The mol­ecules are bent at the S atom, with C—SO2—NH—CH2 torsion angles of ?67.3?(2) and 67.7?(3)° in mol­ecules A and B, respectively. Further, the dihedral angles between the sulfonyl­glycine segments and the p-toluene­sulfonyl rings are 76.1?(1) and 85.8?(1)° in mol­ecules A and B, respectively. The central hydrazone segments and the toluene rings attached to them are almost co-planar with their mean planes being inclined to one another by 5.2?(2) (mol­ecule A) and 2.9?(2)° (mol­ecule B). The dihedral angles between the benzene rings are 86.83?(12) (mol­ecule A) and 74.00?(14)° (mol­ecule B). In the crystal, the A mol­ecules are linked by a pair of N—H?O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. The dimers are linked via three N—H?O hydrogen bonds involving the B mol­ecules, forming chains along [100] and enclosing R 2 2(12) and R 4 4(16) ring motifs. The chains are linked via C—H?O hydrogen bonds and a C—H?? inter­action, forming sheets parallel to (010). There is a further C—H?? inter­action and a slipped parallel ?–? inter­action [inter-centroid distance = 3.8773?(16)?Å] between the sheets, leading to the formation of a three-dimensional framework. PMID:26090163

  18. Combination of photocatalysis downstream the non-thermal plasma reactor for oxidation of gas-phase toluene

    International Nuclear Information System (INIS)

    Ozone is an undesirable byproduct of non-thermal plasma (NTP) for volatile organic compounds (VOCs) control. Photocatalysis combined downstream the NTP reactor and ozone was utilized to oxidize toluene. The multiple synergies of O3/UV/TiO2 system and the mechanism of toluene decomposition were investigated. The influence factors such as energy density, humidity and UV sources were also intensively studied. The combination of photocatalysis in the post-plasma increased the conversion of toluene and ozone to almost 80 and 90%, respectively. Water vapor played a dual role in toluene destruction and ozone removal. In total, 0.75% humidity had the best conversion of toluene and ozone at these experimental conditions. The conversion of toluene enhanced with increasing ozone removal. Among the multiple oxidation processes in the O3/UV/TiO2 system, the O3/TiO2 process played a key role in the decomposition of toluene.

  19. Hydrogen bonding in the benzene-ammonia dimer

    Science.gov (United States)

    Rodham, David A.; Suzuki, Sakae; Suenram, Richard D.; Lovas, Frank J.; Dasgupta, Siddharth; Goddard, William A., III; Blake, Geoffrey A.

    1993-01-01

    High-resolution optical and microwave spectra of the gas-phase benzene-ammonia dimer were obtained, showing that the ammonia molecule resides above the benzene plane and undergoes free, or nearly free, internal rotation. To estimate the binding energy (De) and other global properties of the intermolecular potential, theoretical calculations were performed for the benzene-ammonia dimer, using the Gaussian 92 (Fritsch, 1992) program at the MP2/6-31G** level. The predicted De was found to be at the lowest end of the range commonly accepted for hydrogen bonding and considerably below that of C6H6-H2O, consistent with the gas-phase acidities of ammonia and water. The observed geometry greatly resembles the amino-aromatic interaction found naturally in proteins.

  20. 40 CFR 80.1334 - What are the requirements for early compliance with the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ...FUEL ADDITIVES Gasoline Benzene Hardship Provisions...compliance with the gasoline benzene program? (a)(1) A refinery may comply with the benzene requirements at...gasoline by processing crude and/or...

  1. Molecular Origin of Thermal Diffusion in Benzene+Cyclohexane Mixtures

    International Nuclear Information System (INIS)

    The isotope effect in thermal diffusion (Soret effect) of benzene+cyclohexane mixtures has been investigated by a holographic grating technique. The Soret coefficient can be split into additive contributions. One contribution, the isotope effect, stems from the differences of both mass and moment of inertia, and is independent of composition. An additional ''chemical'' contribution depends on concentration and even changes its sign at a benzene mole fraction xbenz?0.7 . The mass effect is in agreement with molecular dynamics calculations: the heavier component migrates to the cold side

  2. Molecular origin of thermal diffusion in benzene + cyclohexane mixtures.

    Science.gov (United States)

    Debuschewitz, C; Köhler, W

    2001-07-30

    The isotope effect in thermal diffusion (Soret effect) of benzene+cyclohexane mixtures has been investigated by a holographic grating technique. The Soret coefficient can be split into additive contributions. One contribution, the isotope effect, stems from the differences of both mass and moment of inertia, and is independent of composition. An additional "chemical" contribution depends on concentration and even changes its sign at a benzene mole fraction x(benz) approximately 0.7. The mass effect is in agreement with molecular dynamics calculations: the heavier component migrates to the cold side. PMID:11497788

  3. Benzene formation in the inner regions of protostellar disks

    CERN Document Server

    Woods, P M; Woods, Paul M.; Willacy, Karen

    2006-01-01

    Benzene (c-C6H6) formation in the inner 3 AU of a protostellar disk can be efficient, resulting in high abundances of benzene in the midplane region. The formation mechanism is different to that found in interstellar clouds and in protoplanetary nebulae, and proceeds mainly through the reaction between allene (C3H4) and its ion. This has implications for PAH formation, in that some fraction of PAHs seen in the solar system could be native rather than inherited from the interstellar medium.

  4. Coal chemistry. 8. Reactions of tetralin with coal and with some carbon-14-containing model compounds

    International Nuclear Information System (INIS)

    When coal was treated with tetralin-l-14C at 4000C, small yields of ?- and ?-methylnaphthalenes-14C were observed. In order to determine the mechanism of the reaction, tetralin was heated with 14C-labeled 1,3-diphenylpropanes (1), with 1,3-diphenylpropene (2), and with 14C-labeled phenetoles (3). In each case methylnaphthalenes were observed, and the origins of the methyl groups were determined with carbon-14. In addition to the methylnaphthalenes, 1 and 2 also yielded toluene and ethylbenzene (after 19 h), whereas phenetole-?-14C (3-?-14C) yielded toluene (unlabeled) plus ethyl-14C-benzene, benzene, phenol, and a mixture of ?- and ?-ethyl-14C-naphthalenes. Crossover experiments with labeled phenetole and unlabeled ethyl p-tolyl ether proved the intramolecularity of the reaction phenetole ? toluene + ethylbenzene, thus illustrating a 1,2-phenyl shift from oxygen to carbon

  5. 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

  6. 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

  7. 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.

  8. Total cross section of solid mesitylene, toluene and a mixture of them at thermal neutron energies

    International Nuclear Information System (INIS)

    The total neutron cross sections of mesitylene, toluene and a solution 3:2 by volume of mesitylene and toluene were measured at the electron LINAC based pulsed neutron source of Centro Atomico Bariloche. Measurements were performed at 180 K, 120 K and 31.6 K for mesitylene and at 120 K and 31.6 K for toluene and a solution 3:2 by volume of mesitylene and toluene. The systems are potential moderator materials to be considered in the design of a cold neutron source due to their high resistance to radiation and the richness in low-energy excitations of their frequency spectra, that lead to produce an enhanced cold neutron flux.

  9. Plasma induced toluene decomposition on alumina-supported Mn-based composite oxides catalysts

    International Nuclear Information System (INIS)

    This paper presents a two-stage hybrid plasma catalyst system for toluene decomposition in air. It consists of a dielectric barrier discharge reactor and Mn-based composite oxides catalysts. Experimental results show that removal efficiency of toluene was 10 % by only plasma, but a 100 % destruction efficiency as well as 100% ozone removal was achieved by plasma catalysis at a specific energy density of 28.8 J L?1. The catalytic decomposition efficiency of toluene and ozone produced in the first stage is in the following order: NTP+ Mn-Co/Al > NTP + Mn-Ce/Al > NTP+ Mn-Ni/Al > NTP. Compared to other catalysts coupled with non-thermal plasma in a two-stage plasma catalytic reactor, the alumina-supported Mn-based composite oxides catalysts showed a better performance for toluene and ozone removals, especially the Mn-Co/Al catalyst.

  10. Physiology of toluene-degrading pseudomonas strains under variuous conditions of nutrient limitation in chemastat culture

    OpenAIRE

    Duetz, Wouter Adriaan

    1996-01-01

    This thesis is concerned with the influence of the growth conditions on the physiology of bacteria capable of degrading toluene and other monoaromatic hydrocarbons. Unless state do therwise, the experiments were performed with Pseudomonasp utida mt-2. Zie: Summary

  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. Photodecomposition of gaseous toluene using TiO2 prepared by SANSS

    International Nuclear Information System (INIS)

    This study examined the photodecomposition of volatile organic compounds (VOCs) using TiO2 catalyst fabricated by the submerged arc nanoparticle synthesis system (SANSS). The TiO2 catalyst was employed to decompose gaseous toluene and compared with Degussa-P25 TiO2 in terms of decomposition efficiency. It was found that gaseous toluene exposed to UV irradiation produced intermediates that were even harder to decompose. After 60-min of photocomposition, Degussa-P25 TiO2 reduced the concentration of gaseous toluene to 8.18% while the concentration after decomposition by SANSS TiO2 catalyst dropped to 0.35%. The results show that TiO2 prepared by SANSS has great efficiency in decomposing both gaseous toluene and its intermediates

  13. Determination of substituted benzenes in water samples by fiber-in-tube liquid phase microextraction coupled with gas chromatography.

    Science.gov (United States)

    Wang, Jun-Xia; Jiang, Dong-Qing; Yan, Xiu-Ping

    2006-01-15

    A method for determination of toluene, ethylbenzene, p-xylene, o-xylene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene in water samples was developed by a fiber-in-tube liquid phase microextraction technique (fiber-in-tube LPME) coupled with GC-flame ionization detector (FID). The method used a tube packed with polytetrafluoroethylene (PTFE) fibers as an extraction medium, improving the stableness of the solvent and the performance of extraction. Certain amounts of curled PTFE fibers were packed into a section of PTFE tube. Because the fibers were curled, they formed network structure in the tube. The fiber packed tube was firstly immersed into organic solvent to be filled with organic solvent and then was exposing to an aqueous solution to extract the target compounds. The extract was then retracted by a conventional GC microsyringe and analyzed by GC-FID. Extraction of the analytes in 8 ml aqueous solution for 15 min yielded enrichment factors of 224-361. The precision (R.S.D., n=5) was 3.6-8.1% for peak area. The limit of detection (LOD, S/N=3) for the six substituted benzenes were in the range of 0.3-5.0 microgl(-1). PMID:18970414

  14. Benzene homologues in environmental matrixes from a pesticide chemical region in China: Occurrence, health risk and management.

    Science.gov (United States)

    Wang, Tieyu; Bo, Pang; Bing, Tan; Zhaoyun, Zhu; Liyu, Du; Yonglong, Lu

    2014-06-01

    The contamination status and health risks of benzene, toluene, ethylbenzene and xylene (BTEX) in air, soil, dust and groundwater were evaluated in a pesticide chemical region located in Hebei province, China. The concentrations of BTEX in air ranged from 7.80 to 238ug/m(3) and those in soil and dust ranged from lower than limit of detection (LOD) to 32,360ng/g dw, and those in groundwater varied from 2.68 to 98.6ug/L. Generally, the levels of BTEX in multimedia matrixes were all below the standards established in China. Health risk assessment was performed based on the monitoring data via inhalation, dermal contact and ingestion pathways and hazard quotient (HQ) was calculated to be on the order of 10(-7), below 10(-6), and Hazard index (HI) levels of BTEX were lower than 1.0. However, both HQ and HI ascended with an increase in work experience/exposure. Integrated risk management was proposed to eliminate BTEX pollution and to protect occupational health of workers in those industries. PMID:24736026

  15. 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.

  16. 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

  17. Increased leukemia-associated gene expression in benzene-exposed workers

    OpenAIRE

    Keqiu Li; Yaqing Jing; Caihong Yang; Shasha Liu; Yuxia Zhao; Xiaobo He; Fei Li; Jiayi Han; Guang Li

    2014-01-01

    Long-term exposure to benzene causes several adverse health effects, including an increased risk of acute myeloid leukemia. This study was to identify genetic alternations involved in pathogenesis of leukemia in benzene-exposed workers without clinical symptoms of leukemia. This study included 33 shoe-factory workers exposed to benzene at levels from 1?ppm to 10?ppm. These workers were divided into 3 groups based on the benzene exposure time, 1- < 7, 7- < 12, and 12- < 24 years. 17 indivi...

  18. Effects of intraperitoneal application of toluene dissolved in propylene glycol on erythropoiesis in Wistar rats

    OpenAIRE

    Kova?evi?-Filipovi? Milica; Z?, Stevanovic? Jelka; Boži? Tatjana P.; Petakov Marijana D.

    2004-01-01

    The potential toxic effect of toluene on erythropoiesis was investigated during the enhanced erythropoietic activity provoked by application of propylene glycol (known as a mild hemolytic agent) in adult female Wistar rats. The animals were treated daily for 3, 7 or 11 days, with an intraperitoneal dose of toluene dissolved in propylene glycol (T+PG) or propylene glycol (PG) alone. The effects of T+PG and PG on some hematological parameters in peripheral blood and bone marrow were evaluated a...

  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.; Field, J. A.

    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. Urinary hippuric acid and orthocresol excretion in man during experimental exposure to toluene.

    OpenAIRE

    Døssing, M.; Aelum, J B; Hansen, S.H.; Lundqvist, G. R.; Andersen, N. T.

    1983-01-01

    It is not known whether urinary excretion of hippuric acid (HA) or orthocresol (O-Cr) is to be preferred for the biological monitoring of workers with occupational exposure to toluene. To study this, 42 printing trade workers with more than 10 years' exposure to a mixture of organic solvents including toluene (0-20 ppm) and 43 control subjects matched by age, smoking habits, and living accommodation were investigated. Each matched pair was randomised to an experimental exposure of either 100 ...