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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.)

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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)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2008-03-01

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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)

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.

K. L. Shivabasappa

2008-03-01

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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)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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.

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

2073-20-01

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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

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Comparison of measurement methods for benzene and toluene  

Science.gov (United States)

Diffusive sampling and active (pumped) sampling (tubes filled with Tenax TA or Carbopack B) were compared with an automatic BTX instrument (Chrompack, GC/FID) for measurements of benzene and toluene. The measurements were made during differing pollution levels and different weather conditions at a roof-top site and in a densely trafficked street canyon in Stockholm, Sweden. The BTX instrument was used as the reference method for comparison with the other methods. Considering all data the Perkin-Elmer diffusive samplers, containing Tenax TA and assuming a constant uptake rate of 0.406 cm3 min-1, showed about 30% higher benzene values compared to the BTX instrument. This discrepancy may be explained by a dose-dependent uptake rate with higher uptake rates at lower dose as suggested by laboratory experiments presented in the literature. After correction by applying the relationship between uptake rate and dose as suggested by Roche et al. (Atmos. Environ. 33 (1999) 1905), the two methods agreed almost perfectly. For toluene there was much better agreement between the two methods. No sign of a dose-dependent uptake could be seen. The mean concentrations and 95% confidence intervals of all toluene measurements (67 values) were (10.80±1.6) ?g m -3 for diffusive sampling and (11.3±1.6) ?g m -3 for the BTX instrument, respectively. The overall ratio between the concentrations obtained using diffusive sampling and the BTX instrument was 0.91±0.07 (95% confidence interval). Tenax TA was found to be equal to Carbopack B for measuring benzene and toluene in this concentration range, although it has been proposed not to be optimal for benzene. There was also good agreement between the active samplers and the BTX instrument.

Wideqvist, U.; Vesely, V.; Johansson, C.; Potter, A.; Brorström-Lundén, E.; Sjöberg, K.; Jonsson, T.

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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)

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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)

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Dermal exposure assessment to benzene and toluene using charcoal cloth pads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Charcoal cloth pads have been used to assess volatile chemicals on the skin in a laboratory setting; however, they have not yet been applied to measure dermal exposure in occupational settings. This study aimed at evaluating whether charcoal pads can be used to assess dermal exposure to benzene and toluene in workers of a petrochemical plant. Inhalation and dermal exposure levels to benzene and toluene were assessed for workers of a petrochemical plant performing different jobs. Benzene uptak...

Joode, B. V.; Tielemans, E.; Vermeulen, R.; Wegh, H. C. P.; Kromhout, H.

2005-01-01

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

Science.gov (United States)

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.

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

2007-01-01

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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

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 (d...

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

2007-01-01

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

International Nuclear Information System (INIS)

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

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Dermal exposure assessment to benzene and toluene using charcoal cloth pads.  

Science.gov (United States)

Charcoal cloth pads have been used to assess volatile chemicals on the skin in a laboratory setting; however, they have not yet been applied to measure dermal exposure in occupational settings. This study aimed at evaluating whether charcoal pads can be used to assess dermal exposure to benzene and toluene in workers of a petrochemical plant. Inhalation and dermal exposure levels to benzene and toluene were assessed for workers of a petrochemical plant performing different jobs. Benzene uptake was assessed by determining S-phenylmercapturic acid in workers' urine samples. Dermal exposure levels on the charcoal pads were adjusted for ambient air levels of benzene and toluene by subtracting the amount of benzene or toluene measured in personal air from the amount of benzene or toluene measured on the charcoal pad. In general, measured external and internal exposure levels were low. The estimated contribution of the dermal route to internal benzene exposure levels was less than 0.06% for all jobs. Toluene personal air concentrations and benzene and toluene dermal exposure levels differed statistically significantly between job titles. For benzene, differences between jobs were larger for adjusted dermal exposures (maximum 17-fold, P = 0.02) than for inhalation exposures (maximum two-fold, P = 0.08). Also for toluene, although less clear, differences between jobs were larger for adjusted dermal exposures (maximum 23-fold, P = 0.01) as compared to inhalation exposures (maximum 10-fold, P = 0.01). Charcoal pads appeared to measure dermal exposures to benzene and toluene in addition to ambient air levels. Future studies applying charcoal cloth pads for the dermal exposure assessment at workplaces with higher dermal exposure to organic solvents may provide more insight into the biological relevance of dermal exposure levels measured by charcoal cloth pads. In addition, the design of the dermal sampler might be improved by configuring a dermal sampler, where part of the sampler is protected against direct contact and splashes, but still permeable for the gas phase. This design would most likely result in a better ability to correct for airborne concentrations at a given body location. PMID:15083162

van Wendel de Joode, Berna; Tielemans, Erik; Vermeulen, Roel; Wegh, Hillion; Kromhout, Hans

2005-01-01

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Effects of toluene and benzene air mixtures on human lung cells (A549).  

Science.gov (United States)

Human epithelial lung cells (A549) were exposed to toluene and benzene in the air as individual compounds and mixtures at concentrations of about 0.25ppmv in a specifically adapted fumigation device. Possible early toxicological effects at cellular level have been determined by lactate dehydrogenase (LDH), glutathione redox status (GSH) and comet assay. An hour of exposure to 0.25ppmv of toluene in the air induced DNA damages which were repaired within 24h after the treatment. No DNA damage was detected by applying a similar concentration of benzene, but there was a decrease in the glutathione ratio. Exposure to a mixture of toluene and benzene in air led to an increase in the cytotoxic effect and DNA damage without any further repair, but did not induce any changes in the glutathione redox status. PMID:19046626

Pariselli, F; Sacco, M G; Ponti, J; Rembges, D

2009-07-01

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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

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Catalytic hydroxylation of benzene and toluene by an iron complex bearing a chelating di-pyridyl-di-NHC ligand.  

Science.gov (United States)

This work reports on iron-catalysed hydroxylation of benzene and toluene using aqueous H2O2. While benzene is hydroxylated with a high selectivity to phenol, toluene is hydroxylated to cresols with a high selectivity for the ortho and para-position. An inverse KIE indicates the presence of a high valent Fe=O species during catalysis. PMID:24840886

Raba, Andreas; Cokoja, Mirza; Herrmann, Wolfgang A; Kühn, Fritz E

2014-10-01

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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

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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

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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

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

International Nuclear Information System (INIS)

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

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Ethyl benzene should be considered ototoxic at occupationally relevant exposure concentrations.  

Science.gov (United States)

Organic solvents can produce ototoxic effects in both man and experimental animals. The objective of this study was to review the literature on the effects of low-level exposure to ethyl benzene on the auditory system and consider its relevance for the occupational settings. Both human and animal investigations were evaluated only for realistic exposure concentrations based on the permissible exposure limits. In Quebec, the Time-Weighed Average Exposure Value for 8A h (TWAEV) is 100A ppm (434A mg/m(3)) and the Short-Term Exposure Value for 15A min (STEV) is 125A ppm (543A mg/m(3)). In humans, the upper limit for considering ototoxicity data relevant to the occupational exposure situation was set at STEV. Animal data were evaluated only for exposure concentrations up to 100 times the TWAEV. In workers, there is no evidence of either ethyl benzene-induced hearing losses or ototoxic interaction after combined exposure to ethyl benzene and noise. In rats, ethyl benzene affects the auditory function mainly in the cochlear mid-frequency range and ototoxic interaction was observed after combined exposure to noise and ethyl benzene. Further studies with sufficient data on the ethyl benzene exposure of workers are necessary to make a definitive conclusion. Given the current evidence from animal studies, we recommend considering ethyl benzene as an ototoxic agent. PMID:19022877

Vyskocil, A; Leroux, T; Truchon, G; Lemay, F; Gendron, M; Gagnon, F; El Majidi, N; Viau, C

2008-05-01

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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

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Analysis of benzene, toluene, ethylbenzene and m-xylene in biological samples from the general population.  

Science.gov (United States)

A method for the determination of benzene, toluene, ethylbenzene and xylene in blood and urine of people not occupationally exposed to solvents is described. The headspace technique combined with gas chromatography with a mass spectrometer detector is used. The sensitivity of recent mass spectrometers is good enough to furnish reliable results also in biological samples collected from the general population. No treatment for concentrating solvents present in the blood or urine is necessary. The main features of the method are easy preparation of biological samples, small volumes (7 ml), good repeatability and linearity in the range of interest. The limits of detection in blood were 16, 43, 22 and 52 ng/l for benzene, toluene, ethylbenzene and m-xylene respectively. Slightly greater sensitivity was found for urine samples. The results obtained in biological samples from 25 woodworkers not occupationally exposed to BTEX (15 non-smokers and 10 smokers) are comparable to those obtained by other investigators. PMID:12376127

Perbellini, Luigi; Pasini, Francesco; Romani, Serena; Princivalle, Andrea; Brugnone, Francesco

2002-10-01

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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)

26

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)

27

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

28

Separation of aromatic hydrocarbons (toluene or benzene) from aliphatic hydrocarbon (n-heptane) by extraction with ethylene carbonate  

International Nuclear Information System (INIS)

Selectivity factors and partition coefficients of ethylene carbonate and the (ethylene carbonate + sulfolane) solvent mixture for the separation of benzene or toluene from (benzene or toluene + n-heptane) are obtained from the experimental (liquid + liquid) equilibrium data for ternary mixtures of (ethylene carbonate + benzene or toluene + n-heptane) at temperatures of (303.15 and 313.15) K and quaternary mixture of (ethylene carbonate + sulfolane + benzene + n-heptane) at 303.15 K. The composition of liquid phases at equilibrium was determined by gas-liquid chromatography and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The parameters of the models were evaluated and reported. The phase diagrams for the mixtures studied are presented and the correlated tie line results have been compared with the experimental results. The comparisons indicate the applicability of the UNIQUAC and NRTL activity coefficients model for (liquid + liquid) equilibrium calculations of the mixtures studied.

29

Separation of aromatic hydrocarbons (toluene or benzene) from aliphatic hydrocarbon (n-heptane) by extraction with ethylene carbonate  

Energy Technology Data Exchange (ETDEWEB)

Selectivity factors and partition coefficients of ethylene carbonate and the (ethylene carbonate + sulfolane) solvent mixture for the separation of benzene or toluene from (benzene or toluene + n-heptane) are obtained from the experimental (liquid + liquid) equilibrium data for ternary mixtures of (ethylene carbonate + benzene or toluene + n-heptane) at temperatures of (303.15 and 313.15) K and quaternary mixture of (ethylene carbonate + sulfolane + benzene + n-heptane) at 303.15 K. The composition of liquid phases at equilibrium was determined by gas-liquid chromatography and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The parameters of the models were evaluated and reported. The phase diagrams for the mixtures studied are presented and the correlated tie line results have been compared with the experimental results. The comparisons indicate the applicability of the UNIQUAC and NRTL activity coefficients model for (liquid + liquid) equilibrium calculations of the mixtures studied.

Mohsen-Nia, M., E-mail: m.mohsennia@kashanu.ac.i [Thermodynamic Research Laboratory, University of Kashan, Kashan (Iran, Islamic Republic of); Department of Chemical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Mohammad Doulabi, F.S. [Thermodynamic Research Laboratory, University of Kashan, Kashan (Iran, Islamic Republic of)

2010-10-15

30

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

Energy Technology Data Exchange (ETDEWEB)

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).

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

2009-12-23

31

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

International Nuclear Information System (INIS)

Ways of energy dissipation resulting from Eu(fod)3 electronic excitation in homological series of solvents-benzene, toluene and o-xylene have been studied. It is ascertained that probability of the electronic excitation energy degradation increases with an increase in the number of methyl groups at aromatic ring. The values of the activation energy of Eu(fod)3 chelate excited state quenching, which correlate with the number of methyl groups in the series benzene (35.6±1.3 kJ/mol), toluene (39.3±1.3 kJ/mol), o-xylene (54.4±0.8 kJ/mol), have been determined. The results obtained suggest that the main contribution to Eu(3+) electronic excitation energy degradation in homological series benzene, toluene, o-xylene is made by nonradiating energy transfer to high-frequency overtones of oscillations in the solvent C-H groups

32

High energy electron beam generation of oxidants for the treatment of benzene and toluene in the presence of radical scavengers  

International Nuclear Information System (INIS)

High energy electron beam irradiation of benzene and toluene in aqueous solution results in their destruction and the formation of highly oxidized reaction byproducts. The product distribution depends upon absorbed dose and pH and results from the reaction of benzene and toluene with the hydroxyl radical (OH·), followed by continued oxidation of intermediate by-products. The dose required to remove 99% (D0.99) of the benzene from solution, at an initial solute concentration of 17.0 ? M (1.3 mg l-1), was 95 krad. In presence of a known radical scavenger, i.e. 3.3 mM methanol, a dose of 1510 krad was required to achieve the same removal. Toluene showed greater removal, in the absence of methanol, than benzene under similar experimental condition. The D0.99 required to destroy an initial toluene concentration of 47.7 ?M (4.4 mg l-1) was 165 krad, whereas the D0.99 for an initial toluene concentration of 16.4 ? M, in the presence of 3.3 mM methanol, was 2074 krad. (Author)

33

Evaluation of Occupational Exposure of Shoe Makers to Benzene and Toluene Compounds in Shoe Manufacturing Workshops in East Tehran  

Science.gov (United States)

Background Shoe making is among the oldest traditional occupations. Hazardous chemical substances such as adhesives containing benzene and toluene are used in the manufacturing process. Due to the lack of studies on exposure of shoemakers to benzene and toluene in Iran, this study was organized aiming at evaluating occupational exposure and risk assessment in shoemakers. Materials and Methods Overall, 48 shoemakers (12 workshops) in East Tehran were selected randomly for this study. Personal exposure of shoemakers in four different task groups of cutting, modeling, fitting and finishing was examined during three consecutive months (October, November and December) with different climatic conditions. Sampling and analysis of samples were based on an OSHA method (Method No.12). Results The results of personal monitoring of subjects’ exposure to benzene and toluene in each of the three consecutive months (Mean ± standard error) were 1.10± 0.11, 1.37 ± 0.14 and 1.52 ± 0.18ppm, 11.78 ± 1.77, 14.87 ± 1.71 and 16.08 ± 2.31ppm respectively. Due to climatic temperature changes from October to December and restriction of air flow due to closure of windows and shut down of general ventilation systems, a general trend of increased exposure was noticed. However, the difference among these three examinations was not statistically significant. Shoemakers in four task groups did not have statistically significant differences in exposure to benzene and toluene. The severity of shoemaker's exposure to toluene was significantly correlated with the number of manufactured shoes and the amount of glue used for the process. Conclusion Considering the magnitude of personal exposure of task groups to benzene and toluene which was higher than TLV-TWA and unacceptably high risk of cancer and non-cancerous diseases in these subjects, improvement of work conditions for shoemakers seems imperative. PMID:25191437

Hosseini, Vajihe; Jafari, Mohammad Javad; Soori, Hamid; Asadi, Parisa; Mousavion, Seid Mohammad Ali

2012-01-01

34

Chapter 13 Theoretical and Experimental Studies of the Gas-Phase Cl-Atom Initiated Reactions of Benzene and Toluene  

Science.gov (United States)

The reactions of benzene (Bz) and toluene (PhMe) with chlorine atoms in the gas phase have been studied using both theoretical and experimental techniques. Energy and geometry of reaction complexes and transition states were calculated in the Cl-atom initiated reaction of benzene and toluene using modern hybrid functional PBE0 method with the aug-pc1 basis set with an additional CCSD(T)/aug-CC-pVDZ energy single point calculation. Three stationary structures have been found for the Bz...Cl complex: hexahapto-complex, [pi]-complex and [sigma]-complex. The first one is a transition state between two opposite [pi]-complexes. PhMe...Cl has additional structures due to ipso-, ortho-, meta- and para-isomerization. The stability of all calculated complexes was determined and compared. Two reaction pathways for benzene and toluene with a Cl atom were evaluated: (a) the hydrogen abstraction of benzene and toluene by Cl atom, which is seemingly barrierless and endothermic, and (b) the hydrogen substitution reaction that in contrast has a relatively high energy of activation. Rate coefficients for these same reactions were measured using ethane, n-butane, and chloro-, dichloro- and trichloromethane, as reference compounds, with gas chromatography equipped with mass detection spectrometry and flame ionization detection (GC-MSD and GC-FID). The reaction rates were estimated as (5.57±0.15)×10-11 and for benzene and toluene, respectively. Chlorinated products of the reactions were analyzed by GS-MS. Chlorobenzene was the only identified product between a reaction of benzene and the Cl atom. The major products of the PhMe + Cl reaction were chloromethylbenzene with ortho- and para-chlorotoluenes.

Ryzhkov, A.; Ariya, P. A.; Raofie, F.; Niki, H.; Harris, G. W.

35

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)

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.)

Dupont, L.

2001-02-01

36

Heats of adsorption of benzene and toluene vapors on polyhydroxyaluminum montmorillonite  

Science.gov (United States)

Changes that occur in the surface properties and porous structure of montmorillonite when sodium ions are replaced with polyhydroxyaluminum ions are studied. It is established that thermal evacuation significantly affects the adsorption and energy properties of polyhydroxyaluminum montmorillonite (PHAM). The dependences of the differential isosteric heats of adsorption and desorption on the amount of adsorbed substance are determined from data on a series of isosteres for the sorption of benzene and toluene on dehydrated PHAMs, where the curves of the heats of sorption of C6H6 and C7H8 are of an extreme character. It is concluded that the occurrence of maxima is determined by the interaction between molecules of adsorbates and active centers (and with one another) due to packing upon the filling of the volumes of slittype micropores.

Muminov, S. Z.; Khandamov, D. A.; Agzamkhodzhaev, A. A.

2014-09-01

37

UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho-, and para-xylene  

International Nuclear Information System (INIS)

New measurements of the absorption cross sections of gaseous benzene, toluene, meta-, ortho-, and para-xylene have been performed with a Fourier transform spectrometer Bruker IFS120 M at the resolution of 1 cm-1 over the 30 000-42 000 cm-1 spectral range. The recordings were carried out under different pressure and temperature conditions with pure samples. The effect of the temperature on the absorption cross sections is investigated. Comparison with the literature shows large differences, largely attributed to the experimental difficulties encountered during these previous measurements and to a resolution effect. To our knowledge, it is the first time that such a dataset of UV absorption cross sections with temperature dependence is reported in the literature. Such data should be useful for upcoming remote sensing applications, such as atmospheric studies both on Earth and on other planets.

38

N-Cyclo­hexyl-N-ethyl­benzene­sulfonamide  

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The title compound, C14H21NO2S, synthesized by N-methyl­ation of cyclo­hexyl­amine sulfonamide with ethyl iodide is of inter­est as a precursor to biologically active sulfur-containing heterocyclic compounds. There are two independent mol­ecules in the asymmetric unit. The dihedral angles between the mean planes of the phenyl ring and the cyclo­hexyl ring are 40.29?(11) and 37.91?(13)° in the two mol­ecules.

Khan, Islam Ullah; Haider, Zeeshan; Zia-ur-rehman, Muhammad; Arshad, Muhammad Nadeem; Shafiq, Muhammad

2009-01-01

39

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.

40

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

 
 
 
 
41

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

Science.gov (United States)

One major drawback of ion mobility spectrometry (IMS) is the dependence of the response to a certain analyte on the concentration of water or the presence of other compounds in the sample gas. Especially for low proton affine analytes, e.g., benzene, which often exists in mixtures with other volatile organic compounds, such as toluene and xylene (BTX), a time-consuming preseparation is necessary. In this work, we investigate BTX mixtures using a compact IMS operated at decreased pressure (20 mbar) and high kinetic ion energies (HiKE-IMS). The reduced electric field in both the reaction tube and the drift tube can be independently increased up to 120 Td. Under these conditions, the water cluster distribution of reactant ions is shifted toward smaller clusters independent of the water content in the sample gas. Thus, benzene can be ionized via proton transfer from H3O(+) reactant ions. Also, a formation of benzene ions via charge transfer from NO(+) is possible. Furthermore, the time for interaction between ions and neutrals of different analytes is limited to such an extent that a simultaneous quantification of benzene, toluene, and xylene is possible from low ppbv up to several ppmv concentrations. The mobility resolution of the presented HiKE-IMS varies from R = 65 at high field (90 Td) to R = 73 at lower field (40 Td) in the drift tube, which is sufficient to separate the analyzed compounds. The detection limit for benzene is 29 ppbv (2 s of averaging) with 3700 ppmv water, 12.4 ppmv toluene, and 9 ppmv xylene present in the sample gas. Furthermore, a less-moisture-dependent benzene measurement with a detection limit of 32 ppbv with ca. 21?000 ppmv (90% relative humidity (RH) at 20 °C) water present in the sample gas is possible evaluating the signal from benzene ions formed via charge transfer. PMID:25360539

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

2014-12-01

42

N-Cyclo­hexyl-N-ethyl-4-methyl­benzene­sulfonamide  

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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.

Haider, Zeeshan; Arshad, Muhammad Nadeem; Simpson, Jim; Khan, Islam Ullah; Shafiq, Muhammad

2009-01-01

43

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

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

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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.

Sanghamitra Barman

2010-01-01

45

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

Science.gov (United States)

The capacity of a periodic mesoporous organosilica (PMO) to adsorb the aromatic compounds benzene, toluene, o-, and p-xylenes (BTX), which are usually present in produced waters, was investigated under both column and batch processes. The PMO was synthesized by condensation of 1,4 bis(triethoxisilyl)benzene (BTEB) under acidic conditions by using structure-directing agent (SDA) Pluronic P123 in the presence of KCl. Thermogravimetric analysis showed that the presence of the surfactant decreases the thermal stability of the PMO. The small-angle X-ray diffraction pattern, as well as the nitrogen adsorption/desorption isotherm measurements, revealed that the synthesized material has a crystalline structure, with hexagonally-ordered cylindrical mesopores. The adsorption kinetics study indicated an adsorption equilibrium time of 50 min and also showed that the data best fitted the pseudo-first order kinetic model. The intraparticle diffusion model was also tested and pointed to the occurrence of such process in all cases. Both Langmuir and Temkin models best represented the adsorption isotherms of toluene; Langmuir and Redlich-Peterson models best represented the data obtained for the other compounds. Adsorption capacity decreases in the order benzene>o-xylene>p-xylene>toluene. Satisfactory results were observed in the application of the synthesized PMO for the removal of BTX from aqueous solution. PMID:21868024

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

2011-11-15

46

Subclinical effects of groundwater contaminants. Pt. 4. Effects of repeated oral exposure to combinations of benzene and toluene on regional brain monoamine metabolism in mice  

Energy Technology Data Exchange (ETDEWEB)

The effect of combined treatment with benzene and toluene on the endogenous concentrations of the catecholamines norepinephrine (NE) and dopamine (DA), the catecholamine metabolites vanillylmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the indoleamine serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), were investigated in six discrete brain regions of CD-1 mice. Groups of male, adult mice were continuously exposed to benzene (166 mg/l), toluene (80 and 325 mg/l), and combinations of benzene + toluene (80 or 325 mg/l) in drinking water for 4 weeks. Benzene produced increases of NE in the hypothalamus, cortex, midbrain and medulla oblongata, DA in the hypothalamus and corpus striatum, and 5-HT in all dissected brain regions except cerebellum. Elevated levels of various monoamine metabolites were also observed in these brain areas. Toluene ingestion alone also significantly increased the concentrations of NE, DA, 5-HT, and their metabolites in several brain regions. Mice given the combined treatments exhibited raised regional neurochemical levels when compared to the untreated controls. Increased concentrations of biogenic amine metabolites in several brain regions were greater in the combined exposures of benzene and toluene than when either chemical was used alone. The findings were different from those observed on immune parameters using similar treatment protocols, where simultaneous exposure to toluene prevented the immunotoxic effects of benzene. (orig./MG).

Hsieh, G.C.; Parker, R.D.R. (Utah State Univ., Logan, UT (USA). Dept. of Biology); Sharma, R.P. (Utah State Univ., Logan, UT (USA). Dept. of Animal, Dairy and Veterinary Sciences)

1990-11-01

47

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

48

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

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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.

H Heidari

2012-05-01

49

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

International Nuclear Information System (INIS)

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

50

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)

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 yielded a trimodal distribution indicating that these compounds predominantly share the same or co-located sources within the city and that a significant fraction of NOx is directly emitted as NO2. 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 ± 0.3 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 for ozone in the mid-afternoon (~40 ppbv O3) all at 360 ± 10 m a.g.l.

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

2014-10-01

51

A comparative investigation on catalytic oxidation of CO, benzene, and toluene over birnessites derived from different routes  

Science.gov (United States)

Catalytic oxidation of CO, benzene, and toluene was studied over the octahedral layered birnessites (OL-1, OL-2, OL-3, and OL-4) derived from different routes. Physicochemical properties of the samples were characterized by a number of different analytical techniques. It is found that all of the samples have birnessite-type octahedral layered structure and an interlayer spacing of ca. 0.72 nm. Surface areas and pore volumes of the OL-3 and OL-4 samples were much higher than those of the OL-1 and OL-2 samples. There was co-presence of Mn3+, Mn4+ and/or Mn2+ on the surface of these samples. Based on the manganese ion contents, the average oxidation states of surface Mn species in the birnessite samples were in the range of 3.2-3.5, which was lower than those (3.5-3.9) obtained from the H2-TPR studies. The amounts of oxygen vacancies and lattice oxygen mobility of the OL-1 and OL-4 samples were higher than those of the OL-2 and OL-3 samples. Either in CO oxidation or in benzene or toluene oxidation, the catalytic activity decreased in the order of OL-1 > OL-4 >> OL-3 > OL-2, with the OL-1 sample showing the best performance (T50% = 115 and T100% = 150 °C for CO oxidation at 15,000 mL/(g h), T50% = 200 °C and T95% = 240 °C for benzene oxidation, and T50% = 190 °C and T95% = 230 °C for toluene oxidation at 40,000 mL/(g h)). We conclude that catalytic performance of the octahedral layered birnessite samples was associated with the Mn oxide nature, surface lattice oxygen mobility, and reducibility.

Ye, Qing; Lu, Heng; Zhao, Jun; Cheng, Shuiyuan; Kang, Tianfang; Wang, Dao; Dai, Hongxing

2014-10-01

52

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

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Full Text Available A comprehensive evaluation of the adverse health effects of human exposures to BTX from service station emissions was carried out using BTX exposure data from the scientific literature. The data was grouped into different scenarios based on activity, location and occupation and plotted as Cumulative Probability Distributions (CPD plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ at 50% (CEXP50 and 95% (CEXP95 exposure levels. HQ50 and HQ95 > 1 were obtained with benzene in the scenario for service station attendants and mechanics repairing petrol dispensing pumps indicating a possible health risk. The risk was minimized for service stations using vapour recovery systems which greatly reduced the benzene exposure levels. HQ50 and HQ95 < 1 were obtained for all other scenarios with benzene suggesting minimal risk for most of the exposed population. However, HQ50 and HQ95 < 1 was also found with toluene and xylene for all scenarios, suggesting minimal health risk. The lifetime excess Cancer Risk (CR and Overall Risk Probability for cancer on exposure to benzene was calculated for all Scenarios and this was higher amongst service station attendants than any other scenario.

Benjamin Edokpolo

2014-06-01

53

Infrared spectroscopy of gas phase benzenium ions: protonated benzene and protonated toluene, from 750 to 3400 cm-1.  

Science.gov (United States)

Gas phase C 6H 7 (+) and C 7H 9 (+) ions are studied with infrared photodissociation spectroscopy (IRPD) and the method of rare gas tagging. The ions are produced in a pulsed electric discharge supersonic expansion source from benzene or toluene precursors. We observe exclusively the formation of either the C 2 v benzenium ion (protonated benzene) or the para isomer of the toluenium ion (protonated toluene). The infrared spectral signatures associated with each ion are established between 750 and 3400 cm (-1). Comparing the gas phase spectrum of the benzenium ion to the spectrum obtained in a superacid matrix [ Perkampus, H. H.; Baumgarten, E. Angew. Chem. Int. Ed. 1964, 3, 776 ], we find that the C 2 v structure of the gas phase species is minimally affected by the matrix environment. An intense band near 1610 cm (-1) is observed for both ions and is indicative of the allylic pi-electron density associated with the six membered ring in these systems. This spectral signature, also observed for alkyl substituted benzenium ions and protonated naphthalene, compares favorably with the interstellar, unidentified infrared emission band near 6.2 microm (1613 cm (-1)). PMID:18459757

Douberly, G E; Ricks, A M; Schleyer, P v R; Duncan, M A

2008-06-01

54

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)

55

Redetermination of ethyl-ene-diammonium bis-(p-methyl-benzene-sulfonate) monohydrate.  

Science.gov (United States)

In the asymmetric unit of the title compound, C(2)H(10)N(2) (2+)·2C(7)H(7)O(3)S(-)·H(2)O, there are two independent 4-methyl-benzene-sulfonate anions, one ethyl-enediammonium cation and a water mol-ecule. The present redetermination was carried out to improve the treatment of disorder, which was not refined in the previous study [Ahn & Kim (1985 ?). J. Korean Chem. Soc.29, 335-340]. One of the sulfonate groups is disordered over two positions, with site-occupancy factors of 0.588?(14) and 0.412?(14). Inter-molecular N-H?O and O-H?O hydrogen bonds hold the three components together, affording a layer structure extending parallel to the (001) plane. PMID:21200908

Shen-Tu, Chao; Ma, Lin-Lin; Xu, Wei; Chen, Ying; Jin, Zhi-Min

2007-01-01

56

Redetermination of ethyl­ene­diammonium bis­(p-methyl­benzene­sulfonate) monohydrate  

Science.gov (United States)

In the asymmetric unit of the title compound, C2H10N2 2+·2C7H7O3S?·H2O, there are two independent 4-methyl­benzene­sulfonate anions, one ethyl­enediammonium cation and a water mol­ecule. The present redetermination was carried out to improve the treatment of disorder, which was not refined in the previous study [Ahn & Kim (1985 ?). J. Korean Chem. Soc. 29, 335–340]. One of the sulfonate groups is disordered over two positions, with site-occupancy factors of 0.588?(14) and 0.412?(14). Inter­molecular N—H?O and O—H?O hydrogen bonds hold the three components together, affording a layer structure extending parallel to the (001) plane. PMID:21200908

Shen-Tu, Chao; Ma, Lin-Lin; Xu, Wei; Chen, Ying; Jin, Zhi-Min

2008-01-01

57

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)

58

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

59

Analytical method for evaluation of exposure to benzene, toluene, xylene in blood by gas chromatography preceded by solid phase microextraction.  

Science.gov (United States)

Frequency of intentional exposure to organic solvents has been increasing among children and adolescents in Brazil. Analysis of benzene, toluene and xylenes (BTX) in human blood is necessary to diagnose the intentional and accidental exposure to these solvents. A method for BTX determination in blood samples by gas chromatography preceded by solid phase microextration (SPME) from headspace (HS) has been described. SPME has several advantages when compared to other extraction techniques such as simplicity, low cost and solvent-free extraction. The method presents good repeatability (precision was of 2.2-8.0%), accuracy from -4.7 to -9.4%, limit of detection 0.99), which shows to be efficient and adequate for the detection of exposure to BTX in blood samples. PMID:15282110

Alegretti, Ana Paula; Thiesen, Flavia V; Maciel, Gisele P

2004-09-25

60

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

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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

Cimi A Daniel

2013-12-01

 
 
 
 
61

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-09-15

62

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

63

Simultaneous determination of gasoline oxygenates and benzene, toluene, ethylbenzene and xylene in water samples using headspace-programmed temperature vaporization-fast gas chromatography-mass spectrometry.  

Science.gov (United States)

A sensitive method is presented for the fast analysis of seven fuel oxygenates (methanol, ethanol, tert-butyl alcohol (TBA), methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and diisopropyl ether (DIPE)) and benzene, toluene, ethylbenzene and p-xylene (BTEX) in water samples. The applicability of a headspace (HS) autosampler in combination with a GC device equipped with a programmable temperature vaporizer (PTV) and a MS detector is explored. The proposed method achieves a clear improvement in sensitivity with respect to conventional headspace methods due to the use of the PTV. Two different packed liners with materials of different trapping strengths (glass wool and Tenax-TA) were compared. The benefits of using Tenax-TA instead of glass wool as packed material for the measurement of the 11 compounds emerged as better signal-to-noise ratios and hence better detection limits. The proposed method is extremely sensitive. The limits of detection are of the order of ng/L for six of the compounds studied and of the order of microg/L for the rest, with the exception of the most polar and volatile compound: methanol. Precision (measured as the relative standard deviation for a level with an S/N ratio close to 3) was equal to or lower than 15% in all cases. The method was applied to the determination of the analytes in natural matrixes (tap, river and sea water) and the results obtained can be considered highly satisfactory. The methodology has much lower detection limits than the concentration limits proposed in drinking water by the US Environmental Protection Agency (EPA) and the European Union for compounds under regulation. PMID:17980893

Pérez Pavón, José Luis; del Nogal Sánchez, Miguel; Fernández Laespada, María Esther; Moreno Cordero, Bernardo

2007-12-14

64

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

Science.gov (United States)

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 for a single weekday in 1995. The proportion of vehicles in "stop-go" mode, an 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 micrograms/m3, respectively) and from 16 school sites with moderate concentrations (means: 2.6, 32.2, and 5.7 micrograms/m3, respectively) were measured from 1996 to 1998. Statistical analysis of the data was performed using components of two different statistical models recently used to predict air pollution levels in comparable settings. Two traffic characteristics, traffic volume and traffic jam percentage, adequately described air pollutant concentrations (R2: 0.76-0.80, P literature. PMID:12483801

Carr, David; von Ehrenstein, Ondine; Weiland, Stephan; Wagner, Claudia; Wellie, Oliver; Nicolai, Thomas; von Mutius, Erika

2002-10-01

65

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

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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.

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

2004-10-01

66

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

International Nuclear Information System (INIS)

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

67

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

68

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)

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)

Gonzalez Vanderhaghen, D.E

1998-12-31

69

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

Science.gov (United States)

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

Ding, Liang; Cupples, Alison M

2015-01-01

70

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

Science.gov (United States)

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

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

2014-01-01

71

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

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

Abdulrahman Bahrami

2011-01-01

72

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)

Full Text Available SciELO Argentina | Language: English Abstract in english 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.

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

2010-07-01

73

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

Science.gov (United States)

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

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

2015-02-01

74

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

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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.

Dong-Zhi Chen

2014-12-01

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

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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 contained 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.

Daoxiang Zhang

2011-01-01

76

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)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

77

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

International Nuclear Information System (INIS)

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

78

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

Science.gov (United States)

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

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

2014-11-01

79

(Vapour + liquid) equilibria of (1-butanol + benzene, or toluene, or o-, or m-, or p-xylene) at T=308.15 K  

International Nuclear Information System (INIS)

(Vapour + liquid) equilibria (VLE) data of (1-butanol + benzene, or toluene, or o-, or m-, or p-xylene) measured by the static method at T=(308.15 ± 0.01) K over the entire composition range are reported. The excess molar Gibbs free energies of mixing GEm for these binary systems have been calculated from total vapour pressure data using Barker's method. The GEm for these binary systems are also analyzed in terms of the Mecke-Kempter type of association model with a Flory contribution term using two interaction parameters and it has been found that this model describes well the GEm values of these binary systems

80

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

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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...

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

2013-01-01

 
 
 
 
81

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

82

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-15

83

Ultrasonic velocities in, and adiabatic compressibilities for, binary liquid mixtures of 1,2-dichloroethane with benzene, toluene, p-xylene, quinoline, and cyclohexane  

Energy Technology Data Exchange (ETDEWEB)

Measurements of ultrasonic velocities ..mu.. and adiabatic compressibilities (k/sub s/) have been made for mixtures of 1,2-dichloroethane (CH/sub 2/ClCH/sub 2/Cl) with benzene, toluene, and quinoline at 303.15 and 313.15 K, for mixtures of CH/sub 2/ClCH/sub 2/Cl with p-xylene at 303.15 and 318.15 K, and for mixtures of CH/sub 2/ClCH/sub 2/Cl with cyclohexane at 308.15 K. The values of the quantity ..delta..k/sub s'/ which refers to the deviations of the experimental values of k/sub s/ for mixtures from the mole fraction mixture law values, have been found to be positive for CH/sub 2/ClCH/sub 2/Cl-benzene, CH/sub 2/ClCH/sub 2/Cl-toluene, CH/sub 2/ClCH/sub 2/Cl-p-xylene, and CH/sub 2/ClCH/sub 2/Cl-cyclohexane, and negative for CH/sub 2/ClCH/sub 2/Cl-quinoline.

Nath, J.; Singh, G.

1986-07-01

84

Combined application of conservative transport modelling and compound-specific carbon isotope analyses to assess in situ attenuation of benzene, toluene, and o-xylene  

Science.gov (United States)

In recent years, compound specific isotope analyses (CSIA) have developed into one of the most powerful tools for the quantification of in situ biodegradation of organic contaminants. In this approach, the calculation of the extent of biodegradation of organic contaminants in aquifers is usually based on the Rayleigh equation, and thus neglects physical transport processes such as dispersion that contribute to contaminant dilution in aquifers. Here we combine compound specific isotope analyses with a conservative transport model to study the attenuation of aromatic hydrocarbons at a former gasworks site. The conservative transport model was first used to simulate concentration reductions caused by dilution at wells downgradient of a BTEX source. In a second step, the diluted concentrations, together with the available stable carbon isotope ratios and carbon fractionation factors for benzene, toluene and o-xylene were applied in the Rayleigh equation to quantify the degree of biodegradation at each of those wells. At the investigated site, where other attenuation processes such as sorption and volatilisation were proven to be negligible, the combined approach is recommended for benzene, which represents a compound for which the effect of biodegradation is comparable to or less than the effect of dilution. As demonstrated for toluene and o-xylene, the application of the Rayleigh equation alone is sufficient if dilution can be proved to be insignificant in comparison to biodegradation. The analysis also suggests that the source width and the position of the observation wells relative to the plume center line are significantly related to the degree of dilution.

Mak, K. S.; Griebler, C.; Meckenstock, R. U.; Liedl, R.; Peter, A.

2006-12-01

85

Survival and reproduction of some blue-green and green algae as affected by sewage water, fertilizer factory effluent, brassica oil, phenol, toluene and benzene.  

Science.gov (United States)

Fourteen blue-green and green algae survived for widely different time periods ranging between 22-102 d in control culture medium. Irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different morphological types or natural habitats, they all survived for a short time period ranging between 3-8 d in sewage water, 5-10 d in fertilizer factory effluent, (1/4)-2 d in brassica oil, (1/2)-2 d in phenol, 1-3 d in toluene, and 1-4 d in benzene (showing the relative toxicity of different chemicals to different algae, and the antialgal nature of brassica oil). Dilution decreased the toxicity of these agents very little, indicating that they all were very toxic to algae. None of the agent induced the formation of any reproductive or dormant cells. Sewage water, fertilizer factory effluent, brassica oil and/or benzene favored the formation of necridia cells in Phormidium bohneri, P. foveolarum, Microcoleus chthonoplastes, Lyngbya birgei, and L. major filaments. Scenedesmus quadricauda shed off all spines earlier, Hormidium flaccidum fragmented less or not at all, Scytonema millei formed no false branch and heterocyst, Aphanothece pallida and Gloeocapsa atrata cells did not divide, Cosmarium granatum cells did not form any zygospore and Oedogonium sp. not any oogonia-like cells under all or most of treatments with 25-100 % sewage water, 1-100 % fertilizer factory effluent, 1-100 % brassica oil, 25-100 % phenol, toluene and benzene. PMID:19330547

Agrawal, S C; Gupta, S

2009-01-01

86

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)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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.

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

87

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

88

Thermodynamic properties of (tetradecane + benzene, + toluene, + chlorobenzene, + bromobenzene, + anisole) binary mixtures at T = (298.15, 303.15, and 308.15) K  

International Nuclear Information System (INIS)

Density ?, viscosity ?, and refractive index n D, values for (tetradecane + benzene, + toluene, + chlorobenzene, + bromobenzene, + anisole) binary mixtures over the entire range of mole fraction have been measured at temperatures (298.15, 303.15, and 308.15) K at atmospheric pressure. The speed of sound u has been measured at T = 298.15 K only. Using these data, excess molar volume V E, deviations in viscosity ??, Lorentz-Lorenz molar refraction ?R, speed of sound ?u, and isentropic compressibility ?k s have been calculated. These results have been fitted to the Redlich and Kister polynomial equation to estimate the binary interaction parameters and standard deviations. Excess molar volumes have exhibited both positive and negative trends in many mixtures, depending upon the nature of the second component of the mixture. For the (tetradecane + chlorobenzene) binary mixture, an incipient inversion has been observed. Calculated thermodynamic quantities have been discussed in terms of intermolecular interactions between mixing components

89

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

90

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)

91

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

Science.gov (United States)

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 the number of rRNA operons, dioxygenases, monooxygenases, genomic islands (GIs), and heavy metal resistance genes. A high abundance of phage integrases and GIs and the patterns in several other genetic measures (e.g., GC content, GC skew, Karlin signature, and clustered regularly interspaced short palindromic repeat [CRISPR] gene homology) indicated that strain BD-a59's genomic architecture may have been altered through horizontal gene transfers (HGT), phage attack, and genetic reshuffling during its evolutionary history. The genes for benzene/toluene, ethylbenzene, and xylene degradations were encoded on GI-9, -13, and -21, respectively, which suggests that they may have been acquired by HGT. We used bioinformatics to predict the biodegradation pathways of the six BTEX compounds, and these pathways were proved experimentally through the analysis of the intermediates of each BTEX compound using a gas chromatograph and mass spectrometry (GC-MS). The elevated abundances of dioxygenases, monooxygenases, and rRNA operons in strain BD-a59 (relative to strain 11-1), as well as other genomic characteristics, likely confer traits that enhance ecological fitness by enabling strain BD-a59 to degrade hydrocarbons in the soil environment. PMID:23160122

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

2013-01-01

92

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

Science.gov (United States)

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.

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

2011-12-01

93

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)

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

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

2013-11-01

94

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

95

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2009-01-01

96

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)

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)

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

97

Thermodynamic properties of (tetradecane + benzene, + toluene, + chlorobenzene, + bromobenzene, + anisole) binary mixtures at T = (298.15, 303.15, and 308.15) K  

Energy Technology Data Exchange (ETDEWEB)

Density {rho}, viscosity {eta}, and refractive index n {sub D}, values for (tetradecane + benzene, + toluene, + chlorobenzene, + bromobenzene, + anisole) binary mixtures over the entire range of mole fraction have been measured at temperatures (298.15, 303.15, and 308.15) K at atmospheric pressure. The speed of sound u has been measured at T = 298.15 K only. Using these data, excess molar volume V {sup E}, deviations in viscosity {delta}{eta}, Lorentz-Lorenz molar refraction {delta}R, speed of sound {delta}u, and isentropic compressibility {delta}k {sub s} have been calculated. These results have been fitted to the Redlich and Kister polynomial equation to estimate the binary interaction parameters and standard deviations. Excess molar volumes have exhibited both positive and negative trends in many mixtures, depending upon the nature of the second component of the mixture. For the (tetradecane + chlorobenzene) binary mixture, an incipient inversion has been observed. Calculated thermodynamic quantities have been discussed in terms of intermolecular interactions between mixing components.

Mutalik, Venkatesh [Department of Chemistry, Karnatak University, Dharwad 580 003 (India); Manjeshwar, Lata S. [Department of Chemistry, Karnatak University, Dharwad 580 003 (India)]. E-mail: latamanjeshwar@yahoo.com; Sairam, Malladi [Center of Excellence in Polymer Science, Karnatak University, Dharwad 580 003 (India); Aminabhavi, Tejraj M. [Center of Excellence in Polymer Science, Karnatak University, Dharwad 580 003 (India)]. E-mail: aminabhavi@yahoo.com

2006-08-15

98

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

99

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)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2014-09-01

100

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

Directory of Open Access Journals (Sweden)

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

Wouter A. Herrebout

2013-06-01

 
 
 
 
101

Excess molar volumes and refractive indices of (methoxybenzene+benzene, or toluene, or o-xylene, or m-xylene, or p-xylene, or mesitylene) binary mixtures between T=(288.15 to 303.15)K  

International Nuclear Information System (INIS)

Densities ? and refractive indices nD for (anisole+benzene, or toluene, or o-xylene, or m-xylene or p-xylene or mesitylene) binary mixtures over the entire range of mole fraction, at temperatures (288.15, 293.15, 298.15, and 303.15)K and atmospheric pressure, have been measured. The excess molar volume VE and molar refraction deviation ?Rm, have been calculated and fitted to the Redlich-Kister polynomial relation to estimate the binary coefficients and standard errors. The excess molar volumes are positive for (anisole+mesitylene) binary mixtures and negative for (anisole+benzene, or toluene, or xylene isomers) binary mixtures at various temperatures. Partial molar volumes V-bar i and partial excess molar volumes V-bar iE have been also derived from the experimental data. The calculated values have been used to explain the dependency of intermolecular interaction between the mixing components on the alkyl substitution on benzene ring

102

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  

Energy Technology Data Exchange (ETDEWEB)

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

Wang Haijun [School of Chemical and Material Engineering, Southern Yangtze University Wuxi, Jiangsu 214036 (China)]. E-mail: wanghjzj@163.com; Wu Yonghua [School of Chemical and Material Engineering, Southern Yangtze University Wuxi, Jiangsu 214036 (China); Huang Jihou [School of Chemical and Material Engineering, Southern Yangtze University Wuxi, Jiangsu 214036 (China)

2006-01-15

103

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

104

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

Energy Technology Data Exchange (ETDEWEB)

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

Baragi, Jagadish G. [Department of Chemistry, Karnatak University, Dharwad 580 003 (India); Aralaguppi, Mrityunjaya I. [Department of Chemistry, Karnatak University, Dharwad 580 003 (India)]. E-mail: Aralaguppi@yahoo.com

2006-12-15

105

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

International Nuclear Information System (INIS)

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

106

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

Energy Technology Data Exchange (ETDEWEB)

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

Villamanan, Rosa M. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, Paseo del Cauce s/n, 47011 Valladolid (Spain)], E-mail: rvillama@dce.uva.es; Segovia, Jose J. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, Paseo del Cauce s/n, 47011 Valladolid (Spain)], E-mail: josseg@eis.uva.es; Carmen Martin, M. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, Paseo del Cauce s/n, 47011 Valladolid (Spain)], E-mail: mcmg@eis.uva.es; Vega-Maza, David [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, Paseo del Cauce s/n, 47011 Valladolid (Spain)], E-mail: davveg@eis.uva.es; Chamorro, Cesar R. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, Paseo del Cauce s/n, 47011 Valladolid (Spain)], E-mail: cescha@eis.uva.es; Villamanan, Miguel A. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, Paseo del Cauce s/n, 47011 Valladolid (Spain)], E-mail: miguel.villamanan@eis.uva.es

2009-02-15

107

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

International Nuclear Information System (INIS)

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

108

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

Energy Technology Data Exchange (ETDEWEB)

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

Chen Dongchu [College of Chemistry and Chemical Engineering, Central South University, Changsha 411083 (China)]. E-mail: dcchen@hnust.edu.cn; Ye Hongqi [College of Chemistry and Chemical Engineering, Central South University, Changsha 411083 (China); Wu Hao [College of Chemistry and Chemical Engineering, Central South University, Changsha 411083 (China)

2007-08-15

109

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

International Nuclear Information System (INIS)

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

110

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2013-09-10

111

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

112

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

Directory of Open Access Journals (Sweden)

Full Text Available Consecutive reactions of adducts, resulting from OH radicals and aromatics, with the tropospheric scavenger molecules O2, NO and NO2 have been studied for benzene, naphthalene, 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.

R. Koch

2007-01-01

113

Sub-acute Toxicity Study of 3,6-Dimethyl-4-Ethyl-O-Acetyl Benzene Isolated from Soil Streptomyces Species  

Directory of Open Access Journals (Sweden)

Full Text Available The sub-acute toxicity study of 3,6-dimethyl-4-ethyl-0-acetyl benzene (BM-5, was carried out on Long Evan`s rats using daily administration (300 ?g/rat/day of compound for 14 consecutive days. Non-significant differences between weight of compound receiving rats and control rats (48?0.816 vs 46?0.816 were found. The change in hematological parameters was found to be nonsignificant (total count of RBC, 5.1?0.081 vs 4.63?0.094; white blood cell, 7.33?0.124 vs 5.73?0.124; platelets, 361666?10274 vs 261666?8498, (cell/ml ?106; percentage of hemoglobin 65.67?1.60 vs 56?0.816; ESR, 25?0.816 vs 19.67?0.471 for experimental and control rats, respectively and biochemical parameters (serum glutamate pyruvate transaminase, 8.5?0.408 vs 8.33 ?0.471 IU L-1; serum glutamate oxaloacetate transaminase, 9.83?0.235 vs 9.33?0.234 IU L-1; bilirubin, 0.36?0.104 vs 0.34?0.016 ?g dL-1; creatinine, 0.67 ?0.089 vs 0.61?0.009 mg dL-1; urea, 18.83?0.235 vs 18.5?0.408 mg dL-1; for experimental and control rats. Therefore, the changes in body weight, hematological and biochemical parameters were statistically non-significant. No detectable abnormalities were found in histopathology of heart, kidney, liver and lung in experimental group of rats as compared with that of the control group of rats.

Bytul M. Rahman

2002-01-01

114

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)

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)

Almeida, Kelly Cristina Santana de

2006-07-01

115

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Gobato, Elaine A. A. F.; Lanc?as, Fernando M.

2001-01-01

116

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

117

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-05-15

118

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)

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.

Xin-Ping Kang

2010-11-01

119

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

International Nuclear Information System (INIS)

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

120

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

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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 ...

1991-01-01

 
 
 
 
121

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)

Full Text Available SciELO Public Health | Language: Spanish Abstract in spanish 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.

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

122

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)

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. PMID:24096064

Muthu, S; Renuga, S

2014-01-24

123

Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl­idene)-4-methyl­benzene­sulfonamide using DFT-D calculations and 13C solid-state NMR  

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The crystal structure of (Z)-N-(5-ethyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl­idene)-4-methyl­benzene­sulfonamide contains an imine tautomer, rather than the previously reported amine tautomer. The tautomers can be distinguished using dispersion-corrected density functional theory calculations and by comparison of calculated and measured 13C solid-state NMR spectra.

Li, Xiaozhou; Bond, Andrew D.; Johansson, Kristoffer E.; Streek, Jacco

2014-01-01

124

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

125

Studies on the mechanism of benzene toxicity.  

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Using the 59Fe uptake method of Lee et al. it was shown that erythropoiesis in female mice was inhibited following IP administration of benzene, hydroquinone, p-benzoquinone, and muconaldehyde. Toluene protected against the effects of benzene. Coadministration of phenol plus either hydroquinone or catechol resulted in greatly increased toxicity. The combination of metabolites most effective in reducing iron uptake was hydroquinone plus muconaldehyde. We have also shown that treating animals w...

Snyder, R.; Dimitriadis, E.; Guy, R.; Hu, P.; Cooper, K.; Bauer, H.; Witz, G.; Goldstein, B. D.

1989-01-01

126

Anticonvulsant and antipunishment effects of toluene  

Energy Technology Data Exchange (ETDEWEB)

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

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

1984-01-01

127

Icosapent Ethyl  

Science.gov (United States)

... are allergic to icosapent ethyl; fish, including shellfish (clams, scallops, shrimp, lobster, crayfish, crab, oyster, mussels, others); ... pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking icosapent ethyl, ...

128

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

Energy Technology Data Exchange (ETDEWEB)

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.

Sweeney, Lynn C.

2013-04-10

129

Bis[8-ethyl-5-oxo-2-(piperazin-4-ium-1-yl)-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carb-oxy-lic acid] 2,5-dicarb-oxy-benzene-1,4-di-carboxyl-ate octa-hydrate.  

Science.gov (United States)

The asymmetric unit of the title compound, 2C(14)H(18)N(5)O(3) (+)·C(10)H(5)O(8) (2-)·8H(2)O, contains one [H(2)ppa](+)cation, one half of an [H(2)btec](2-) anion (H(4)btec = 1,2,4,5-benzene-tetra-carb-oxy-lic acid and Hppa = 8-ethyl-5-oxo-2-piperazin-1-yl-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carb-oxy-lic acid) that is completed by inversion symmetry and four water mol-ecules. In the crystal, the mol-ecules are connected by inter-molecular hydrogen-bonding inter-actions and ?-? stacking between the benzene rings of the [H(2)btec](2-) anion and the pyrimidine rings of the [H(2)ppa](+) cation [centroid-centroid distance = 3.597?(3)?Å], generating a three-dimensional supra-molecular structure. PMID:21754029

Zhang, Guang-Ju; He, Jiang-Hong; Yan, Shi-Wei; Ye, Zhong-Li; Xin, Guang-Hua

2011-04-01

130

Studies on the mechanism of benzene toxicity  

International Nuclear Information System (INIS)

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

131

Studies on the mechanism of benzene toxicity  

Energy Technology Data Exchange (ETDEWEB)

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

Snyder, R.; Dimitriadis, E.; Guy, R.; Hu, P.; Cooper, K.; Bauer, H.; Witz, G.; Goldstein, B.D. (Rutgers, State Univ. of New Jersey, Piscataway (USA))

1989-07-01

132

Cerebellar dysfunction caused by sniffing of toluene-containing thinner  

Energy Technology Data Exchange (ETDEWEB)

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

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

1982-01-01

133

Electron beam degradation of simulated toluene-containing exhaust gas  

International Nuclear Information System (INIS)

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

134

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)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish 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

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

2010-03-01

135

Degradation of toluene by ortho cleavage enzymes in Burkholderia fungorum?FLU100.  

Science.gov (United States)

Burkholderia fungorum?FLU100 simultaneously oxidized any mixture of toluene, benzene and mono-halogen benzenes to (3-substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3-methylcatechol, 4-carboxymethyl-2-methylbut-2-en-4-olide (2-methyl-2-enelactone, 2-ML) accumulated transiently, being further mineralized only after a lag phase of 2?h in case of cells pre-grown on benzene or mono-halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono-halogen benzenes were unable to metabolize 2-ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2-ML as a substrate. This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate. Thus, 3-methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B.?fungorum?FLU100. PMID:25130674

Dobslaw, Daniel; Engesser, Karl-Heinrich

2015-01-01

136

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

137

Radiolysis of Aqueous Toluene Solutions  

Energy Technology Data Exchange (ETDEWEB)

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

Christensen, H.C.; Gustafson, R.

1971-04-15

138

Benzene clusters  

Science.gov (United States)

The infra-red photodissociation of benzene clusters has been studied in the frequency region 1020-1060 cm-1 using a CO2 laser. The infra-red absorption profiles have been measured by monitoring the depletion of signal intensity in a mass spectrometer as a function of laser wavelength for the ion clusters (C6H6)n+ for n = 2 - 10 and (C6H6)2+27. Comparing these results with infra-red data on the various states of benzene, leads to the proposal that the properties of small benzene clusters are best described in terms of a liquid-like rather than a solid-like state. Furthermore, it is suggested that the absorption profile linewidth, which is approximately constant throughout the cluster range investigated, is associated with vibrational dephasing.

Stace, A. J.; Bernard, D. M.; Crooks, J. J.; Reid, K. L.

139

Fenton-like initiation of a toluene transformation mechanism  

Science.gov (United States)

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

140

Toluene emissions from plants  

Science.gov (United States)

The emission of toluene from different plants was observed in continuously stirred tank reactors and in field measurements. For plants growing without stress, emission rates were low and ranged from the detection limit up to 2·10-16 mol·cm-2·s-1. Under conditions of stress, the emission rates exceeded 10-14 mol·cm-2·s-1. Exposure of sunflower (Helianthus annuus L. cv. Gigantheus) to 13CO2 resulted in 13C-labeling of the emitted toluene on a time scale of hours. Although no biochemical pathway for the production of toluene is known, these results indicate that toluene is synthesized by the plants. The emission rates of toluene from sunflower are dependent on nutrient supply and wounding. Since ?-pinene emission rates are also influenced by these factors, toluene and ?-pinene emissions show a high correlation. During pathogen attack on Scots pines (Pinus sylvestris L.) significant toluene emissions were observed. In this case emissions of toluene and ?-pinene also show a good correlation. Toluene emissions were also found in field experiments with pines using branch enclosures.

Heiden, A. C.; Kobel, K.; Komenda, M.; Koppmann, R.; Shao, M.; Wildt, J.

 
 
 
 
141

Ethyl 2-acetylhydrazono-2-phenylacetate  

Directory of Open Access Journals (Sweden)

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.

Liang-Zhong Xu

2008-01-01

142

Poly[ethyl­enediaminium [di-?-aqua-(?6-benzene-1,2,4,5-tetra­carboxyl­ato-?10 O 1,O 1?:O 2,O 2?:O 2?:O 4,O 4?:O 5:O 5,O 5?)dithallium(I)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The title compound, {(C2H10N2)[Tl2(C10H2O8)(H2O)2)]}n, was prepared using (enH2)2(btc)·2H2O and thallium(I) nitrate (en = ethyl­enediamine and btcH4 = benzene-1,2,4,5-tetra­carboxylic acid). The enH2 cation and btc ligand are each located on an inversion centre. The TlI atom is seven-coordinated by three btc ligands and two water mol­ecules in an irregular geometry due to the stereochemically active lone pair on the Tl centre. The water mol­ecule and btc ligand are bonded to the Tl atoms...

Rafizadeh, Masoud; Manteghi, Faranak

2008-01-01

143

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1991-01-01

144

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-10-01

145

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.)

146

Materials balance for benzene: Level II. Final report  

Energy Technology Data Exchange (ETDEWEB)

A Level II materials balance was performed on benzene. Data are reported for benzene production from petroleum by four processes (catalytic reformation, toluene dealkylation, toluene disproportionation, and isolation from pyrolysis gasoline) for production from coal during coking. Amounts of benzene consumed for the synthesis of eight direct derivatives (ethylbenzene, cumene, cyclohexane, nitrobenzene, maleic anhydride, mono- and dichlorobenzene, alkylbenzenes, and biphenyl) and exports are presented. These uses constitute approximately 99 percent of total benzene usage. Nonconsumptive uses (solvents and pesticide component) are also tabulated. Releases due to each of the above processes are reported or estimated where possible using published and unpublished data. In addition, releases due to indirect production (refinery operation, coke oven operations, oil spills, non-ferrous metals manufacturing, ore mining, wood processing, coal mining, and two phases of the textile industry) are presented. Production of benzene as a component of gasoline and releases due to all phases of gasoline use are estimated. Locations of sites with high levels of benzene releases due to production and use are tabulated: the major 'hotspots' are Baton Rouge, Louisiana; Houston/Galveston, Texas; Midland, Michigan; and Puerto Rico. The uncertainty ranges of all numbers used or derived in this report are evaluated when possible and tabulated. Data gaps are evaluated and general recommendations are presented. The results of the report are summarized in two figures: the Environmental Flow Diagram for benzene in Appendix A, and the Materials Balance Flow Diagram in the Executive Summary.

Hall, R.L.; Burger, R.; Montecalvo, F.

1980-05-01

147

Direct Link between Toluene Degradation in Contaminated-Site Microcosms and a Polaromonas Strain ?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stable isotope probing (SIP) was used to identify the aerobic toluene-degrading microorganism in soil microcosms. Several approaches (terminal restriction fragment length polymorphism, 16S rRNA gene sequencing, and quantitative PCR) provided evidence that the microorganism responsible was a member of the genus Polaromonas and could grow on toluene. This microorganism also transformed benzene, but not m-xylene or cis-dichloroethene.

Sun, Weimin; Xie, Shuguang; Luo, Chunling; Cupples, Alison M.

2009-01-01

148

CFD SIMULATIONS OF BENZENE –TOLUENE SYSTEM OVER SIEVE TRAY  

Directory of Open Access Journals (Sweden)

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.

Sumit Singh

2012-08-01

149

Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl­idene)-4-methyl­benzene­sulfonamide using DFT-D calculations and 13C solid-state NMR  

Science.gov (United States)

The crystal structure of the title compound, C11H13N3O2S2, has been determined previously on the basis of refinement against laboratory powder X-ray diffraction (PXRD) data, supported by comparison of measured and calculated 13C solid-state NMR spectra [Hangan et al. (2010 ?). Acta Cryst. B66, 615–621]. The mol­ecule is tautomeric, and was reported as an amine tautomer [systematic name: N-(5-ethyl-1,3,4-thia­diazol-2-yl)-p-toluene­sulfonamide], rather than the correct imine tautomer. The protonation site on the mol­ecule’s 1,3,4-thia­diazole ring is indicated by the inter­molecular contacts in the crystal structure: N—H?O hydrogen bonds are established at the correct site, while the alternative protonation site does not establish any notable inter­molecular inter­actions. The two tautomers provide essentially identical Rietveld fits to laboratory PXRD data, and therefore they cannot be directly distinguished in this way. However, the correct tautomer can be distinguished from the incorrect one by previously reported qu­anti­tative criteria based on the extent of structural distortion on optimization of the crystal structure using dispersion-corrected density functional theory (DFT-D) calculations. Calculation of the 13C SS-NMR spectrum based on the correct imine tautomer also provides considerably better agreement with the measured 13C SS-NMR spectrum. PMID:25093360

Li, Xiaozhou; Bond, Andrew D.; Johansson, Kristoffer E.; Van de Streek, Jacco

2014-01-01

150

Process intensification for the ethyl lactate synthesis : integrated pervaporation reactor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Pereira, C. S. M.; Silva, V. M. T. M.; Pinho, Sima?o; Rodrigues, A. E.

2011-01-01

151

Toluene embryopathy: two new cases.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Hersh, J. H.

1989-01-01

152

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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.

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

153

Facts about Benzene  

Science.gov (United States)

... used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of lubricants, rubbers, dyes, detergents, drugs, and pesticides. How you could be exposed to benzene Outdoor ...

154

Solubilities of some organic solutes in 1-ethyl-3-methylimidazolium acetate. Chromatographic measurements and predictions from COSMO-RS  

International Nuclear Information System (INIS)

Highlights: ? New solubility data are reported. ? Two experimental procedures for measuring solubilities are used. ? The experimental results from both procedures are compared. ? Experiments are compared with the theoretical calculations. - Abstract: Infinite-dilution activity coefficients and Henry’s constants for several organic solutes in 1-ethyl-3-methylimidazolium acetate [EMIM][Ac] were measured from T = 313 K to T = 413 K using two types of gas–liquid chromatography columns: packed columns and an open tubular wall-coated (OTWC) column. The organic solutes include n-hexane, 1-hexene, cyclohexane, heptane, benzene, toluene, ethyl acetate, tetrahydrofuran, 1,4-dioxane, acetonitrile, nitromethane, 1,2-methoxyethane, 1-propanol, 2-propanol, t-butanol and t-amyl alcohol. Results using packed columns are in good agreement with those using the OTWC column. However, there is a useful advantage associated with an OTWC column: for solutes such as alcohols, that have strong interactions with the stationary phase, measurements are faster due to their shorter retention time compared to those in packed columns.

155

Biomonitoring of occupational toluene exposure  

Energy Technology Data Exchange (ETDEWEB)

Toluene exposure was studied in 20 workers employed in painting and hand-finishing in an art furniture factory. Toluene was determined in the environmental air of places of work and in the alveolar air and blood of the workers. Hippuric acid and cresols were also tested in the workers' urine. Blood and urine tests were carried out before the work shift on Monday and Friday morning and at the end of the work shift on Friday afternoon. The other tests were performed on Friday afternoon only. Alveolar toluene concentrations, which were significantly correlated with environmental toluene concentrations (r . 0.6230; P less than 0.01), corresponded to 19.4% of the toluene concentration in the atmosphere. Blood toluene was also found in painters on Monday morning and was significantly correlated with the other parameters. On Friday afternoon it was three times higher than the environmental toluene concentration. Urinary o-Cresol was highly correlated with toluene in the atmosphere, in blood and with hippuric acid in urine. On the basis of the slope of the regression line the ratio between urinary o-Cresol and blood toluene concentration was 0.99. At the end of the work shift urinary hippuric acid concentration was highly correlated with o-Cresoluria and with toluene in blood and in the atmosphere.

Apostoli, P.; Brugnone, F.; Perbellini, L.; Cocheo, V.; Bellomo, M.L.; Silvestri, R.

1982-01-01

156

Biomonitoring of occupational toluene exposure  

Energy Technology Data Exchange (ETDEWEB)

Toluene exposure was studied in 20 workers employed in painting and hand-finishing in an art furniture factory. Toluene was determined in the environmental air of places of work and in the alveolar air and blood of the workers. Hippuric acid and cresols were also tested in the workers' urine. Blood and urine tests were carried out before the work shift on Monday and Friday morning and at the end of the work shift on Friday afternoon. The other tests were performed on Friday afternoon only. Alveolar toluene concentrations, which were significantly correlated with environmental toluene concentrations (..gamma.. = 0.6230; P < 0.01), corresponded to 19.4% of the toluene concentration in the atmosphere. Blood toluene was also found in painters on Monday morning and was significantly correlated with the other parameters. On Friday afternoon it was three times higher than the environmental toluene concentration. Urinary 0-Cresol was highly correlated with toluene in the atmosphere, in blood and with hippuric acid in urine. On the basis of the slope of the regression line the ratio between urinary 0-Cresol and blood toluene concentration was 0.99. At the end of the work shift urinary hippuric acid concentration was highly correlated with 0-Cresoluria and with toluene in blood and in the atmosphere.

Apostoli, P.; Brugnone, F.; Perbellini, L.; Cocheo, V.; Bellomo, M.L.; Silvestri, R.

1982-06-01

157

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-09-15

158

Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.  

Science.gov (United States)

The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge. PMID:25409590

Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

2015-01-01

159

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

160

Quantification of urinary metabolites of principle superior counterpart of benzene; Dosage des metabolites urinaires des principaux homologues superieurs du benzene  

Energy Technology Data Exchange (ETDEWEB)

In the aim of a medical surveillance of personnel exposed to superior counterpart of benzene, it is advisable to measure in urines, the hippuric, methyl hippuric and mandelic acids, as respective biological indicators of exposure to toluene, to xylenes and styrene (chapter 1). In a first time, we give some generalities on principal superior counterparts of benzene and about the biological surveillance of workers exposed to these products. Then, we present the quantification of their urinary metabolites, as it has be done in the stage. (N.C.)

Ruetsch, O. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Dept. de Protection de la Sante de l`Homme et de Dosimetrie]|[Lille-2 Univ., 59 (France)

1997-12-31

 
 
 
 
161

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

162

N-(2,6-Diisopropylphenylformamide toluene 0.33-solvate  

Directory of Open Access Journals (Sweden)

Full Text Available The crystal packing of the title compound, C13H19NO·0.33C7H8, shows a channel at [001], which contains grossly disordered toluene solvent molecules. The angle between the benzene ring and the mean plane of the formamide group is 71.1?(1°. The amide groups of neighbouring molecules are connected by N—H...O hydrogen bonds, forming 21 helical chains propagating along [001]. Molecules are also connected by weak intermolecular C—H...O hydrogen bonds, forming 61 helices.

Norbert Auner

2012-05-01

163

Benzene from Traffic : Fuel Content and Ambient Air Concentrations  

DEFF Research Database (Denmark)

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

Palmgren, F.; Berkowicz, R.

2000-01-01

164

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

Directory of Open Access Journals (Sweden)

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

Ján Hriv?ák

2006-03-01

165

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

International Nuclear Information System (INIS)

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

166

Benzene release. Status report  

International Nuclear Information System (INIS)

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

167

Structures of Benzene Clusters  

Science.gov (United States)

The structures of small benzene clusters (C6H6)n (n=2-8) have been calculated using the discrete variational method (DVM) in the framework of local-density functional approximation (LDA) and molecular dynamics (MD) simulations. The structure of benzene dimer by our calculation is in good agreement with the Hartree-Fock studies. The structure of trimer is first optimized by MD with the intermolecular potential obtained from ab-initio study, and the intramolecule force field of Dreiding. Further calculations are carried out by DVM. We obtain the structure of benzene trimer from first principles calculation, and the optimized structure is a triangle having bloodstrain constructed from the T-type benzene dimer which is expected to be stable experimentally. The structures of tetramer to octamer molecules are obtained by MD and compared with previous calculations and experiments. Consistent structure patterns stemming from the fundamental T-shape dimer are found for all clusters.

Li, Zhiqiang; Ohno, Kaoru; Kawazoe, Yoshiyuki; Mikami, Masuhiro; Masuda, Yuji

168

Benzene Monitor System report  

International Nuclear Information System (INIS)

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

169

Reverse isotope dilution method for determining benzene and metabolites in tissues  

Energy Technology Data Exchange (ETDEWEB)

A method utilizing reverse isotope dilution for the analysis of benzene and its organic soluble metabolites in tissues of rats and mice is presented. Tissues from rats and mice that had been exposed to radiolabeled benzene were extracted with ethyl acetate containing known, excess quantities of unlabeled benzene and metabolites. Butylated hydroxytoluene was added as an antioxidant. The ethyl acetate extracts were analyzed with semipreparative reversed-phase HPLC. Isolated peaks were collected and analyzed for radioactivity (by liquid scintillation spectrometry) and for mass (by UV absorption). The total amount of each compound present was calculated from the mass dilution of the radiolabeled isotope. This method has the advantages of high sensitivity, because of the high specific activity of benzene, and relative stability of the analyses, because of the addition of large amounts of unlabeled carrier analogue.

Bechtold, W.E.; Sabourin, P.J.; Henderson, R.F.

1988-07-01

170

Reverse isotope dilution method for determining benzene and metabolites in tissues  

International Nuclear Information System (INIS)

A method utilizing reverse isotope dilution for the analysis of benzene and its organic soluble metabolites in tissues of rats and mice is presented. Tissues from rats and mice that had been exposed to radiolabeled benzene were extracted with ethyl acetate containing known, excess quantities of unlabeled benzene and metabolites. Butylated hydroxytoluene was added as an antioxidant. The ethyl acetate extracts were analyzed with semipreparative reversed-phase HPLC. Isolated peaks were collected and analyzed for radioactivity (by liquid scintillation spectrometry) and for mass (by UV absorption). The total amount of each compound present was calculated from the mass dilution of the radiolabeled isotope. This method has the advantages of high sensitivity, because of the high specific activity of benzene, and relative stability of the analyses, because of the addition of large amounts of unlabeled carrier analogue

171

Molecular interactions in alcohol-ethyl methacrylate mixtures  

Science.gov (United States)

Molecular interaction between alcohols (1-propanol, 1-butanol, s-butanol, t-butanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) with ethyl methacrylate has been studied in n-heptane, CCl 4 and benzene at 298 K using FTIR spectroscopic and dielectric methods. The result obtained from both the methods indicates only the existence of most likely 1:1 complex formation between the alcohol and ethyl methacrylate in these systems. The alkyl chain length of alcohol and the solvent used play a significant role in the strength of hydrogen bond (O sbnd H:O dbnd C) determined on the basis of spectral and dielectric parameters.

Dharmalingam, K.; Ramachandran, K.; Sivagurunathan, P.; Kalamse, G. M.

2008-02-01

172

Assessment of the Amur River ecosystem pollution with benzene and its derivatives caused by an accident at the chemical plant in Jilin City, China.  

Science.gov (United States)

Assessment of concentrations of benzene and its derivatives in the Amur water and fish caught in summer and autumn 2006 was carried out after Jilin chemical plant accident (winter 2005) in the People’s Republic of China. Fish sampling of Leiocassis ussuriensis conducted in the Amur River near Khabarovsk identified benzene, toluene, ethylbenzene, isopropylbenzene, xylene reaching to 16, 98.7, 55, 54, and 206 ?g kg?1, respectively. For Hypophthalmichtys molitrix Valenciennes sampled in the lower reaches of the Amur benzene, toluene, ethylbenzene, xylene were found in amounts to 9, 15.4, 16 ?g kg?1, and, benzene and xylene reaching 6 and 16 ?g kg?1 were found in Huso dauricus and benzene and xylene of 2–6 and 13–16 ?g kg?1, respectively, in Acipenser schrenckii. The above toxicants were not detected in the Amur water near the river mouth in autumn 2006. PMID:19572090

Levshina, S I; Efimov, N N; Bazarkin, V N

2009-12-01

173

27 CFR 21.132 - Toluene.  

Science.gov (United States)

...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,...

2010-04-01

174

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Burkholderia pickettii PKO1 metabolizes toluene and benzene via a chromosomally encoded toluene-3-monooxygenase pathway. Expression of the toluene-3-monooxygenase operon (tbuA1UBVA2C) is activated by the regulator, TbuT, in the presence of toluene. We have identified the TbuT coding region downstream of the toluene-3-monooxygenase structural genes by nucleotide sequence analysis and have shown that although TbuT is similar to XylR and DmpR, two members of the NtrC family of transcriptional ac...

Byrne, A. M.; Olsen, R. H.

1996-01-01

175

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

Science.gov (United States)

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

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

2007-01-01

176

1-Benzyl­idene-4-ethyl­thio­semicarbazide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The title compound, C10H13N3S, was prepared by the reaction of 4-ethyl­thio­semicarbazide and benzaldehyde. The dihedral angle between the benzene ring and the thio­urea unit is 8.96?(7)° and an intra­molecular N—H?N hydrogen bond generates an S(5) ring. In the crystal, inversion dimers linked by pairs of N—H?S hydrogen bonds generate R 2 2(8) loops.

Li, Yu-feng; Zhang, Yun-cheng

2010-01-01

177

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Sangeetha, J.; Vijayalakshmi, K.

2011-01-01

178

Benzene biodegradation using an anaerobic column coupled to Mn(IV) reduction  

Energy Technology Data Exchange (ETDEWEB)

Benzene, toluene, and o, m, p-xylene compounds make up a large proportion of gasoline. Due to spills and leaks from underground tanks, these compounds frequently contaminate groundwater and sediment. In particular the high solubility of benzene makes it very mobile and an extra danger to groundwater. Moreover, there are strong links between benzene and cancer and thus benzene is considered a serious pollutant. Contaminated sites usually become anaerobic due to microbe action. In this study, benzene biodegradation was done in a glass column inoculated with anaerobic Rhine River sediment and using Mn(IV) as the final electron acceptor. Under steady state operation, benzene biodegradation efficiency was as high as 95 per cent. Carbon dioxide and Mn(II) recovery rates were 81 and 77 per cent respectively. Reactor sediment was withdrawn on day 104 and subject to DGGE profiling. This sediment showed different band patterns than the original sediment that was not exposed to benzene. The authors conclude that the species associated with the degradation of benzene are of the genus Propionibacterium and Actinomyces. 17 refs., 2 figs.

Villatoro-Monzon, W.R.; Velasquez-Mejia, E.K.; Morales-Ibarria, M.G.; Razo-Flores, E. [Instituto Mexicano del Petroleo (Mexico). Programo de Biotenologia del Petroleo

2004-07-01

179

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

Directory of Open Access Journals (Sweden)

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.

Sohail Saeed

2011-02-01

180

Analysis of the gene cluster encoding toluene/o-xylene monooxygenase from Pseudomonas stutzeri OX1.  

Science.gov (United States)

The toluene/o-xylene monooxygenase cloned from Pseudomonas stutzeri OX1 displays a very broad range of substrates and a very peculiar regioselectivity, because it is able to hydroxylate more than one position on the aromatic ring of several hydrocarbons and phenols. The nucleotide sequence of the gene cluster coding for this enzymatic system has been determined. The sequence analysis revealed the presence of six open reading frames (ORFs) homologous to other genes clustered in operons coding for multicomponent monooxygenases found in benzene- and toluene-degradative pathways cloned from Pseudomonas strains. Significant similarities were also found with multicomponent monooxygenase systems for phenol, methane, alkene, and dimethyl sulfide cloned from different bacterial strains. The knockout of each ORF and complementation with the wild-type allele indicated that all six ORFs are essential for the full activity of the toluene/o-xylene monooxygenase in Escherichia coli. This analysis also shows that despite its activity on both hydrocarbons and phenols, toluene/ o-xylene monooxygenase belongs to a toluene multicomponent monooxygenase subfamily rather than to the monooxygenases active on phenols. PMID:9758777

Bertoni, G; Martino, M; Galli, E; Barbieri, P

1998-10-01

 
 
 
 
181

Thermodynamics of mixtures involving some (benzene derivatives+benzonitrile)  

Energy Technology Data Exchange (ETDEWEB)

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 V{sup E} and C{sub p,m}{sup E} are obtained. The magnitude of these experimental quantities together with H{sup E} literature data is discussed in terms of the nature and type of intermolecular interactions in binary mixtures.

Calvo-Iglesias, E. [Departamento de Fisica Aplicada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faencina@usc.es; Bravo, R. [Departamento de Fisica Aplicada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Pintos, M. [Departamento de Fisica Aplicada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Amigo, A. [Departamento de Fisica Aplicada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Roux, A.H. [Thermodynamique des Solutions et des Polymeres, UMR CNRS 6003, Universite Blaise Pascal, 63177 Aubiere cedex (France); Roux-Desgranges, G. [Thermodynamique des Solutions et des Polymeres, UMR CNRS 6003, Universite Blaise Pascal, 63177 Aubiere cedex (France)

2007-04-15

182

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

183

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)

Full Text Available SciELO Colombia | Language: Spanish Abstract in portuguese 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.

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

2012-06-01

184

The use of radioisotopes in radiation chemistry: the effect of radiation on toluene  

International Nuclear Information System (INIS)

The radiation chemistry of organic compounds can often be studied more effectively and in greater detail using compounds labelled with radioisotopes. Use of this approach permits observation of products not otherwise detectable and provides information about the processes by which they are formed. The versatility of this technique is illustrated by results obtained in a study of the radiation chemistry of toluene. Toluene labelled in the methyl group with tritium (one atom per 600 mol.), was prepared and was exposed in the vapour phase to gamma-radiation (1.46 eV/mol.). The product was fractionated and the volatile fractions were injected into a gas fractometer equipped with an ionization chamber to permit simultaneous recording of radioactivity and thermal conductivity. Concentrations of tritium in the various products were determined from relative areas under peaks in the two curves. From the concentrations of tritium in these products it can be deduced that the methane is formed exclusively from the methyl group of toluene and that the xylenes are formed by attack of methyl radicals on toluene. Oxidation of the recovered toluene showed that transfer of tritium from the methyl group, to the benzene ring had occurred to some extent during the irradiation. The benzoic acid contained one tritium atom per 140000 molecules, corresponding to a G value of 0.3 for the ''exchange'' reaction. This appearance of tritium in the ring could result either from abstraction of methyld result either from abstraction of methyl hydrogen by a tolyl radical or from reconversion of a symmetrical intermediate, such as the tropylium ion to toluene. To provide information on this point the irradiation of toluene labelled with carbon-14 is being investigated. (author)

185

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Ján Hriv?ák; Peter Tölgyessy; Eva Krá?ovi?ová

2006-01-01

186

Toluene depresses plasma corticosterone in pregnant rats  

DEFF Research Database (Denmark)

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.

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

2003-01-01

187

Biodegradation of toluene in a trickling filter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Peixoto, J.; Mota, M.

1998-01-01

188

Recurrent asthma induced by toluene diisocyanate.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

1988-01-01

189

Toluene pyrolysis studies and high temperature reactions of propargyl chloride  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1993-12-01

190

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)

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

Cinar, Mehmet; Karabacak, Mehmet

2013-03-01

191

Chemical kinetic study of the oxidation of toluene and related cyclic compounds  

Energy Technology Data Exchange (ETDEWEB)

Chemical kinetic models of hydrocarbons found in transportation fuels are needed to simulate combustion in engines and to improve engine performance. The study of the combustion of practical fuels, however, has to deal with their complex compositions, which generally involve hundreds of compounds. To provide a simplified approach for practical fuels, surrogate fuels including few relevant components are used instead of including all components. Among those components, toluene, the simplest of the alkyl benzenes, is one of the most prevalent aromatic compounds in gasoline in the U.S. (up to 30%) and is a promising candidate for formulating gasoline surrogates. Unfortunately, even though the combustion of aromatics been studied for a long time, the oxidation processes relevant to this class of compounds are still matter of discussion. In this work, the combustion of toluene is systematically approached through the analysis of the kinetics of some important intermediates contained in its kinetic submechanism. After discussing the combustion chemistry of cyclopentadiene, benzene, phenol and, finally, of toluene, the model is validated against literature experimental data over a wide range of operating conditions.

Mehl, M; Frassoldati, A; Fietzek, R; Faravelli, T; Pitz, W; Ranzi, E

2009-10-01

192

Hydrotreating of wheat straw in toluene and ethanol.  

Science.gov (United States)

In the present work, wheat straw was hydroliquefied at a temperature of 300°C for 4h in ethanol or toluene in order to obtain bio-components which are useful for fuel purposes. The experiments were performed in a 100mL batch reactor under hydrogen pressure of 70 bar. Typically, 2g of straw and 0.1g of catalyst (66%Ni/SiO2-Al2O3) were dispersed in 15 g of solvent. The main compounds of the oil produced during the liquefaction of hemicellulose, cellulose and lignin of wheat straw in both solvents are: tetrahydrofuran-2-methanol, 1,2-butanediol and butyrolactone. Besides the mentioned compounds, ethanol favoured the decomposition of bigger molecules to short-chain alcohols such as 1-butanol, 1,2-propanediol and 1,2-ethanediol. Toluene contributes to the production of furans and other cyclic compounds. The light fractions distilled together with the solvent also contain the following: 1-propanol, 2-methyl-cyclopentanone, acetic acid and ethyl acetate. PMID:24787323

Murnieks, Raimonds; Kampars, Valdis; Malins, Kristaps; Apseniece, Lauma

2014-07-01

193

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Nuray Yeksan; Ece Uzkara; Orhan Zeybek; Erol Asker

2010-01-01

194

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Mohamed Akhazzane; Hafid Zouihri; Kella Bennani, A.; Abdelali Kerbal; Ghali Al Houari

2011-01-01

195

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

Directory of Open Access Journals (Sweden)

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.

Mohamed Akhazzane

2011-07-01

196

Ethyl 3-oxo-3H-benzo[f]chromene-2-carboxylate  

Directory of Open Access Journals (Sweden)

Full Text Available In the title compound, C16H12O4, the chromene ring system is almost planar [maximum deviation = 0.026?(1?Å] and makes dihedral angles of 1.24?(9 and 26.5?(2° with the fused benzene ring and the plane of the ethyl carboxylate group, respectively.

H. K. Arunkashi

2010-10-01

197

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Hubert, Casey; Shen, Yin; Voordouw, Gerrit

1999-01-01

198

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2013-01-01

199

21 CFR 520.580 - Dichlorophene and toluene capsules.  

Science.gov (United States)

...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)...

2010-04-01

200

BENZENE OXIDE PROTEIN ADDUCTS AS BIOMARKERS OF BENZENE EXPOSURE  

Science.gov (United States)

Benzene is known to be hematotoxic and carcinogenic in animals and humans. While metabolism is required for toxicity, the identity of the ultimate carcinogen(s) remains unknown. Benzene oxide (BO) is the first and most abundant of the metabolites, but very little is known about...

 
 
 
 
201

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.)

202

Comparative studies on toluene removal and pressure drop in biofilters using different packing materials.  

Science.gov (United States)

To select the best available packing material for malodorous organic gases such as toluene and benzene, biofilter performance was compared in biofilters employed different packing materials including porous ceramic (celite), Jeju scoria (lava), a mixture of granular activated carbon (GAC) and celite (GAC/celite), and cubic polyurethane foam (PU). A toluene-degrading bacterium, Stenotrophomonas maltophilia T3-c, was used as the inoculum. The maximum elimination capacities in the celite, lava, and GAC/celite biofilters were 100, 130, and 110 gm(-3) hr(-1), respectively. The elimination capacity for the PU biofilter was approximately 350 g m(-3) hr(-1) at an inlet loading of approximately 430 g m(-3) hr(-1), which was 2 to 3.5 times higher than for the other biofilters. The pressure drop gradually increased in the GAC/ celite, celite and lava biofilters after 23 day due to bacterial over-growth, and the toluene removal efficiency remarkably decreased with increasing pressure drop. Backwashing method was not effective for the control of biomass in these biofilters. In the PU biofilter however, backwashing allowed maintenance of a pressure drop of 1 to 3 mm H2O m(-1) and a removal efficiency of > 80%, indicating that the PU was the best packing material for toluene removal among the packing materials tested. PMID:21047004

Ryu, Hee Wook; Kim, So Jung; Cho, Kyung Suk

2010-05-01

203

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

204

Methane from benzene in argon dielectric barrier discharge  

Energy Technology Data Exchange (ETDEWEB)

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.

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

205

N-(2,6-Diisopropylphenyl)formamide toluene 0.33-solvate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The crystal packing of the title compound, C13H19NO·0.33C7H8, shows a channel at [001], which contains grossly disordered toluene solvent molecules. The angle between the benzene ring and the mean plane of the formamide group is 71.1?(1)°. The amide groups of neighbouring molecules are connected by N—H...O hydrogen bonds, forming 21 helical chains propagating along [001]. Molecules are also connected by weak intermolecular C—H...O hydrogen bonds...

Norbert Auner; Bats, Jan W.; Matthias Berger

2012-01-01

206

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

International Nuclear Information System (INIS)

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

207

Atmospheric oxidation mechanism of toluene.  

Science.gov (United States)

The atmospheric oxidation mechanism of toluene initiated by OH radical addition is investigated by quantum chemistry calculations at M06-2X, G3MP2-RAD, and ROCBS-QB3 levels and by kinetics calculation by using transition state theory and unimolecular reaction theory coupled with master equation (RRKM-ME). The predicted branching ratios are 0.15, 0.59, 0.05, and 0.14 for OH additions to ipso, ortho, meta, and para positions (forming R1-R4 adducts), respectively. The fate of R2, R4, and R1 is investigated in detail. In the atmosphere, R2 reacts with O2 either by irreversible H-abstraction to form o-cresol (36%), or by reversible recombination to R2-1OO-syn and R2-3OO-syn, which subsequently cyclize to bicyclic radical R2-13OO-syn (64%). Similarly, R4 reacts with O2 with branching ratios of 61% for p-cresol and 39% for R4-35OO-syn, while reaction of R1 and O2 leads to R1-26OO-syn. RRKM-ME calculations show that the reactions of R2/R4 with O2 have reached their high-pressure limits at 760 Torr and the formation of R2-16O-3O-s is only important at low pressure, i.e., 5.4% at 100 Torr. The bicyclic radicals (R2-13OO-syn, R4-35OO-syn, and R1-26OO-syn) will recombine with O2 to produce bicyclic alkoxy radicals after reacting with NO. The bicyclic alkoxy radicals would break the ring to form products methylglyoxal/glyoxal (MGLY/GLY) and their corresponding coproducts butenedial/methyl-substituted butenedial as proposed in earlier studies. However, a new reaction pathway is found for the bicyclic alkoxy radicals, leading to products MGLY/GLY and 2,3-epoxybutandial/2-methyl-2,3-epoxybutandial. A new mechanism is proposed for the atmospheric oxidation mechanism of toluene based on current theoretical and previous theoretical and experimental results. The new mechanism predicts much lower yield of GLY and much higher yield of butenedial than other atmospheric models and recent experimental measurements. The new mechanism calls for detection of proposed products 2,3-epoxybutandial and 2-methyl-2,3-epoxybutandial. PMID:24901213

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

2014-06-26

208

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

Directory of Open Access Journals (Sweden)

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.

Sohail Saeed

2010-04-01

209

Primary atmospheric oxidation mechanism for toluene.  

Science.gov (United States)

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

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

2009-01-01

210

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

International Nuclear Information System (INIS)

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

211

ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI), an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to incr...

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

2011-01-01

212

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

Directory of Open Access Journals (Sweden)

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.

Gema Mikulskiene

2006-01-01

213

Toluene-induced ototoxicity by subcutaneous administration  

Energy Technology Data Exchange (ETDEWEB)

Inhalation exposure of rats to toluene causes irreversible hearing loss (e.g., Pryor et al.). To determine whether noise emanating from the inhalation system was a major contributing factor and whether exposure by a noninhalation route would cause a similar effect, weanling, male Fischer-344 rats were injected SC twice daily in a quiet environment with PEG-300 (control) or with 1.5 or 1.7 g/kg of toluene for 7 days. After being trained to perform a multisensory conditioned avoidance response (CAR) task, tone intensity-response functions were generated at 4, 8, 12, and 20 kHz, and behavioral auditory response thresholds were estimated. Toluene caused a dose-related hearing loss at frequencies of 8 kHz and above, with no effect on performance of the CAR in response to light, nonaversive footshock, or the 4-kHz tone. The similarity of this effect to that observed following inhalation exposure indicates that noise is not a major factor in the toluene-induced hearing loss, although possible interactions between noise and toluene remain to be investigated. These results also demonstrate that direct penetration of the toluene vapors through the external ear structure, as might occur during inhalation exposure, is not a necessary condition for inducing the hearing loss.

Pryor, G.T.; Howd, R.A.

1986-01-01

214

Aerosol formation and decomposition of dilute benzene derivatives by AC/DC corona discharge  

Energy Technology Data Exchange (ETDEWEB)

The most common treatment methods for removing volatile organic compounds (VOCs) include thermal decomposition, catalytic oxidation, carbon adsorption, destruction in non-thermal plasma (NTP) and condensation. Among these technologies, the use of NTP is gaining considerable attention, particularly AC/DC energized corona plasma systems because of their reliable operation, low cost and high efficiency. One of the ideal NTP based processes is to convert VOCs to environmentally sound compounds, such as water. However, since the plasma-initialed reactions are difficult to control, some undesirable products such as aerosols are often observed from VOC removal. The formation of aerosol must therefore be considered in structure-dependent VOC removal characteristics. This study examined the decomposition of three benzene derivatives by novel AC/DC corona discharge with a closed loop flow system in air. The experiments focused primarily on aerosol formation and the individual removal efficiency of benzene, toluene and styrene. The removal process of styrene, benzene and toluene were found to be different from each other because of their different reactivity with radicals. The generated radicals of styrene were efficiently used for the removal process, but the generated radicals of benzene and toluene were mainly quenched by bulk gases. The study showed that a large concentration of aerosols can be generated in humid air. The generated aerosols can be collected by electrostatic precipitation in the AC/DC energized plasma system. It was concluded that the chemical structure is one of most important factors that influence the removal process of VOCs for non-thermal plasma processing. 17 refs., 7 figs.

Zhang, X.; Chen, W.; Zhu, J.; Feng, W.; Yan, K. [Zhejiang Univ., Hangzhou (China). Industrial Ecology and Environment Research Inst.

2010-07-01

215

Substituent effect in benzene dication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

2 Abstract It was r ecently postulated that the benzene ring and its 4n+2 ? - electron analogues are resistant to the substituent effect due to the fact that such systems tend to keep its delocalized character. Therefore, the 4n ? - electron dicationic form of benzene should appear to be less resistant to the substituent effect, as compar ed with its parent neutral molecule. For this reason the effect of substi...

Palusiak, Marcin; Domaga?a, Ma?gorzata; Dominikowska, Justyna; Bickelhaupt, F. Matthias

2014-01-01

216

A fourier transform-ion cyclotron resonance study of steric effects on proton transfer reactions of polyalkyl benzenes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rates of deprotonation, MH+ + B --> M + BH+ (M = 1, 2), and the rates of protonation, M + BH+ --> MH+ + B (M = 2, 3, 4), have been measured by Fourier transform-ion cyclotron resonance (FT-ICR) spectrometry for the increasingly sterically crowded alkyl benzenes ethylbenzene, 1; 1,3,5-trimethylbenzene (mesitylene), 2; 3,5-di-(t-butyl)toluene, 3; 1,3,5-tri(t-butyl) benzene, 4; and a series of n-bases B. In addition, the gas phase basicities of 3 and 4 were determined by proton transfer equ...

Bu?ker, Heinz-hermann; Gru?tzmacher, Hans-friedrich

1991-01-01

217

Benzene emitted from glowing charcoal.  

Science.gov (United States)

Benzene was assessed as the predominant aromatic compound emitted from glowing charcoal and firewood embers. Concentrations measured above charcoal used for grilling exceeded 10 mg m(-3) at a 5% carbon dioxide level. Charcoal with a high carbon content released less benzene. Glowing wood pellets emitted less benzene than glowing firewood remainders. The emissions of ethene and propene relative to benzene were low for commercial charcoal and wood-pellet embers, but high for firewood ember. The proportions of methylbenzene and naphthalene from charcoal were typically only 10% relative to benzene, and those of benzofuran, dibenzofuran and benzonitrile were typically below 5%. The polycyclic aromatic hydrocarbon (PAH) indicator phenanthrene was below the 1% level. Adsorbent sampling and GC-MS were used for assessing all the aromatic compounds. Earlier studies of charcoal emissions have focused on carbon monoxide, PAH and dioxins. It is concluded that the carcinogenic benzene may be an even more severe health hazard to be addressed by exposure-decreasing measures. PMID:12606161

Olsson, Maria; Petersson, Göran

2003-03-01

218

Ethyl 4,9-dimethyl-9H-carbazole-3-carboxyl­ate  

Science.gov (United States)

In the title compound, C17H17NO2, the carbazole skeleton includes an eth­oxy­carbonyl group at the 3-position. The indole three-ring system is almost planar [maximum deviation = 0.065?(2)?Å], and the ethyl ester group is inclined to its mean plane by 15.48?(2)°. In the crystal, there are ?–? stacking inter­actions between parallel benzene rings and between parallel benzene and pyrrole rings of adjacent mol­ecules [centroid–centroid distances = 3.9473?(8) and 3.7758?(8)?Å, respectively]. Weak C—H?? inter­actions are also present. PMID:24764961

Öncüo?lu, Serkan; Dilek, Nefise; Çaylak Deliba?, Nagihan; Ergün, Yavuz; Hökelek, Tuncer

2014-01-01

219

Crystal structure of ethyl 4-[(1H-pyrazol-1-yl)meth­yl]benzoate  

Science.gov (United States)

In the title mol­ecule, C13H14N2O2, the dihedral angle between the pyrazole and benzene ring mean planes is 76.06?(11)°, and the conformation of the ethyl side chain is anti [C—O—C—C = ?175.4?(3)°]. In the crystal, the only directional inter­actions are very weak C—H ?? inter­actions involving both the pyrazole and benzene rings, leading to the formation of a three-dimensional network. PMID:25553050

Wang, Ju-Xian; Feng, Chao

2014-01-01

220

Crystal structure of ethyl 4-[(1H-pyrazol-1-yl)meth-yl]benzoate.  

Science.gov (United States)

In the title mol-ecule, C13H14N2O2, the dihedral angle between the pyrazole and benzene ring mean planes is 76.06?(11)°, and the conformation of the ethyl side chain is anti [C-O-C-C = -175.4?(3)°]. In the crystal, the only directional inter-actions are very weak C-H ?? inter-actions involving both the pyrazole and benzene rings, leading to the formation of a three-dimensional network. PMID:25553050

Wang, Ju-Xian; Feng, Chao

2014-12-01

 
 
 
 
221

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

Directory of Open Access Journals (Sweden)

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].

Yan-Jiao Gao

2013-07-01

222

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

Science.gov (United States)

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. PMID:21837096

Akhazzane, Mohamed; Zouihri, Hafid; Bennani, A. Kella; Kerbal, Abdelali; Al Houari, Ghali

2011-01-01

223

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Akhazzane, Mohamed; Zouihri, Hafid; Bennani, A. Kella; Kerbal, Abdelali; Al Houari, Ghali

2011-01-01

224

4'-Chloro-biphenyl-3-yl 2,2,2-trichloro-ethyl sulfate.  

Science.gov (United States)

The title compound, C(14)H(10)Cl(4)O(4)S, is a 2,2,2-trichloro-ethyl-protected precursor of 4'-chloro-biphenyl-3-yl sulfate, a sulfuric acid ester of 4'-chloro-biphenyl-3-ol. The C(aromatic)-O and O-S bond lengths of the C(aromatic)-O-S unit are comparable to those in structurally analogous biphenyl-4-yl 2,2,2-trichloro-ethyl sulfates with no electro-negative chlorine substituent in the benzene ring with the sulfate ester group. The dihedral angle between the aromatic rings is 27.47?(6)°. PMID:21588655

Li, Xueshu; Parkin, Sean; Duffel, Michael W; Robertson, Larry W; Lehmler, Hans-Joachim

2010-01-01

225

4?-Chloro­biphenyl-3-yl 2,2,2-trichloro­ethyl sulfate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The title compound, C14H10Cl4O4S, is a 2,2,2-trichloro­ethyl-protected precursor of 4?-chloro­biphenyl-3-yl sulfate, a sulfuric acid ester of 4?-chloro­biphenyl-3-ol. The Caromatic—O and O—S bond lengths of the Caromatic—O—S unit are comparable to those in structurally analogous biphenyl-4-yl 2,2,2-trichloro­ethyl sulfates with no electro­negative chlorine substituent in the benzene ring with the sulfate ester group. The dihedral angle between the aromatic rings is 27.47?(6...

Li, Xueshu; Parkin, Sean; Duffel, Michael W.; Robertson, Larry W.; Lehmler, Hans-joachim

2010-01-01

226

(E,E,E)-1,3,5-Tris[4-(acetylsulfanyl)styryl]benzene toluene hemisolvate  

DEFF Research Database (Denmark)

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

SØrensen, Henning Osholm; Magnussen, Magnus

2005-01-01

227

Quantitation methods for the determination of benzene, toluene, ethylbenzene and xylenes in oil contaminated soils  

Energy Technology Data Exchange (ETDEWEB)

Some pretreatment methods for the determination of BTEX content in oil contaminated soil, such as solvent extraction with mechanical shaking, purge and trap and solid phase micro-extraction, were studied. Prepared samples were fine clay, loam and coarse sand which were series of particle size. Those samples were dried in 120 deg.C oven or wetted by adding some reagent water. After then, they were contaminated by spiking BTEX. The results showed that extraction limits and linear dynamic ranges of different extraction methods represented very large differences. So appropriate pretreatment methods were applied to the soil types and BTEX content. (author). 4 refs., 5 tabs.

Jeon, Chi-Wan; Lee, Jung-Hwa; Kim, Sang-Yeon; Choi, Byeng-Ihn [Korea Institute of Geoscience and Mineral Resources, Taejeon(Korea)

2001-06-01

228

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

Directory of Open Access Journals (Sweden)

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.

Majid Kakavand

2004-10-01

229

On the atmospheric oxidation of liquid toluene.  

Science.gov (United States)

This communication presents preliminary computational results on the interaction between triplet (3Sigma) and singlet (1Sigma, 1Delta) oxygen molecules with toluene. All three oxygen species form very weak complexes with toluene and all also appear capable of abstracting a benzylic hydrogen atom to form the HO2 radical. Reaction with singlet molecular oxygen does not convincingly explain the formation of benzylhydroperoxide from toluene residues stored over a long time in brown glass bottles, and it is speculated that this may be a surface-catalysed photochemical reaction. The possible involvement of singlet oxygen molecules in the spontaneous ignition of tyre rubber and of soft coal is discussed briefly and the need for new experimental studies is stressed. PMID:17047753

Pritchard, Huw O

2006-10-21

230

Detection of toluene in an adipoceratous body.  

Science.gov (United States)

A 24-year-old male was found dead in a car left in a river for about 3 months. The cadaver was almost adipoceratous and autopsy findings revealed that there were neither remarkable injuries nor lethal diseases. Toluene, ethanol, 1-propanol, 2-propanol, 1-butanol, dimethyl sulfide, dimethyl disulfide, isovaleraldehyde and n-butyl n-butyrate were detected in the specimens collected at the autopsy by head space gas chromatography/mass spectrometry (GC/MS). The toluene concentrations (micrograms/g) were 31.0 in brain, 10.6 in liver, 5.4 in kidney, 15.0 in skeletal muscle and 187.1 in adipose tissue. The presence of diatom in lung, liver and kidney suggested that death was caused by drowning. So far as we know, this is the first report of detection of toluene in an adipoceratous body. PMID:8621118

Inoue, H; Iwasa, M; Maeno, Y; Koyama, H; Sato, Y; Matoba, R

1996-04-01

231

Crystal structure of ethyl (E-4-(4-chlorophenyl-4-methoxy-2-oxobut-3-enoate  

Directory of Open Access Journals (Sweden)

Full Text Available In the title compound, C13H13ClO4, the dihedral angle between the chlorobenezene ring and the least-squares plane through the 4-methoxy-2-oxobut-3-enoate ethyl ester residue (r.m.s. deviation = 0.0975?Å is 54.10?(5°. In the crystal, molecules are connected by methoxy–ketone and benzene–carboxylate carbonyl C—H...O interactions, generating a supramolecular layer in the ac plane.

Darlene Correia Flores

2014-09-01

232

Benzene hexachloride poisoning in cattle.  

Science.gov (United States)

Of 174 cattle dipped in an emulsified preparation of benzene hexachloride labeled for plant use, 18 were fatally poisoned. The preparation contained 0.14% active ingredient, gamma isomer of benzene hexachloride (BHC), a normally safe concentration for cattle. Analyses revealed 0.08% gamma BHC in the used dip and 0.5, 7.9, and 198 ppm in liver, kidney, and hairskin specimens, respectively, from a fatally affected cow. Microscopic examination of the freshly prepared dip demonstrated emulsion droplets ranging from 5 to 60 mu in diameter. PMID:49345

Ray, A C; Norris, J D; Reagor, J C

1975-06-15

233

Isolation and Characterization of Toluene-Sensitive Mutants from the Toluene-Resistant Bacterium Pseudomonas putida GM73  

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To understand the mechanism underlying toluene resistance of a toluene-tolerant bacterium, Pseudomonas putida GM73, we carried out Tn5 mutagenesis and isolated eight toluene-sensitive mutants. None of the mutants grew in the presence of 20% (vol/vol) toluene in growth medium but exhibited differential sensitivity to toluene. When wild-type cells were treated with toluene (1% [vol/vol]) for 5 min, about 2% of the cells could form colonies. In the mutants Ttg1, Ttg2, Ttg3, and Ttg8, the same tr...

Kim, Kwang; Lee, Sungjin; Lee, Kyunghee; Lim, Dongbin

1998-01-01

234

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

International Nuclear Information System (INIS)

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

235

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...chemical analysis by gas chromatography. Sampling and...disulfide through 13x molecular sieve). 4.2. Benzene...760 mm 78.11=molecular weight of benzene...performance liquid chromatography (HPLC)....

2010-07-01

236

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...access to their employees, to a material safety data sheet (MSDS) which addresses benzene and complies with 29 CFR 1910.1200...CFR 1910.1200, that they deliver to downstream employers an MSDS which addresses benzene. (3) Information and...

2010-07-01

237

The Solubility of Phenylborate Compounds in Benzene  

International Nuclear Information System (INIS)

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

238

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...benzene immediately causes pulmonary edema and hemorrhage of pulmonary tissue. There is some...Symptoms and signs of benzene toxicity can be non-specific...are indicative of potential toxicity, particularly if all...

2010-07-01

239

Intrinsic bioremediability of an aromatic hydrocarbon-polluted groundwater: diversity of bacterial population and toluene monoxygenase genes  

Energy Technology Data Exchange (ETDEWEB)

The functional and phylogenetic biodiversity of bacterial communities in a benzene, toluene, ethylbenzene and xylene (BTEX)-polluted groundwater was analysed. To evaluate the feasibility of using an air sparging treatment to enhance bacterial degradative capabilities, the presence of degrading microorganisms was monitored. The amplification of gene fragments corresponding to toluene monooxygenase (tmo), catechol 1,2-dioxygenase, catechol 2,3-dioxygenase and toluene dioxygenase genes in DNA extracted directly from the groundwater samples was associated with the presence of indigenous degrading bacteria. Five months of air injection reduced species diversity in the cultivable community (as calculated by the Shannon-Weaver index), while little change was noted in the degree of biodiversity in the total bacterial community, as characterised by denaturing gradient gel electrophoresis (DGGE) analysis. BTEX-degrading strains belonged to the genera Pseudomonas, Microbacterium, Azoarcus, Mycobacterium and Bradyrhizobium. The degrading capacities of three strains in batch liquid cultures were also studied. In some of these microorganisms different pathways for toluene degradation seemed to operate simultaneously. Pseudomonas strains of the P24 operational taxonomic unit, able to grow only on catechol and not on BTEX, were the most abundant, and were present in the groundwater community at all stages of treatment, as evidenced both by cultivation approaches and by DGGE profiles. The presence of different tmo-like genes in phylogenetically distant strains of Pseudomonas, Mycobacterium and Bradyrhizobium suggested recent horizontal gene transfer in the groundwater. (orig.)

Cavalca, L.; Dell' Amico, E.; Andreoni, V. [Dipt. di Scienze e Tecnologie Alimentari e Microbiologiche, Univ. degli Studi di Milano, Milan (Italy)

2004-07-01

240

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.

 
 
 
 
241

Toluene Induces Depression-Like Behaviors in Adult Mice  

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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 ...

Yang, Miyoung; Kim, Sung-ho; Kim, Jong-choon; Shin, Taekyun; Moon, Changjong

2010-01-01

242

Benzodiazepine-like discriminative stimulus effects of toluene vapor  

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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...

Shelton, Keith L.; Nicholson, Katherine L.

2013-01-01

243

Omega-3-acid Ethyl Esters  

Science.gov (United States)

... omega-3-acid ethyl esters; fish, including shellfish (clams, scallops, shrimp, lobster, crayfish, crab, oyster, mussels, others); ... pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking omega-3- ...

244

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...15-minute period. 2. Dermal: Eye contact shall be prevented and skin contact with liquid benzene shall be limited. C. Appearance and odor: Benzene...if you inhale it, or if it comes in contact with your skin or eyes. Benzene...

2010-07-01

245

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...allergies and some drugs may raise the white...indication of benzene-induced toxicity. An...sign of benzene-induced toxicity. A less frequent...ultimately develop acute myelogenous leukemia...to have developed acute myelogenous leukemia...aplastic anemias induced by benzene...

2010-07-01

246

Trends in electron-ion dissociative recombination of benzene analogs with functional group substitutions: Negative Hammett ?para values  

Science.gov (United States)

An in-depth study of the effects of functional group substitution on benzene's electron-ion dissociative recombination (e-IDR) rate constant has been conducted. The e-IDR rate constants for benzene, biphenyl, toluene, ethylbenzene, anisole, phenol, and aniline have been measured using a Flowing Afterglow equipped with an electrostatic Langmuir probe (FALP). These measurements have been made over a series of temperatures from 300 to 550 K. A relationship between the Hammett ?para values for each compound and rate constant has indicated a trend in the e-IDR rate constants and possibly in their temperature dependence data. The Hammett ?para value is a method to describe the effect a functional group substituted to a benzene ring has upon the reaction rate constant.

Osborne, David; Lawson, Patrick Andrew; Adams, Nigel; Dotan, Itzhak

2014-06-01

247

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

Directory of Open Access Journals (Sweden)

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

P .Nassiri; F. Golbabai; A. Barzegar

1996-08-01

248

Mixed aggregates of an alkyl lithium reagent and a chiral lithium amide derived from N-ethyl-O-triisopropylsilyl valinol.  

Science.gov (United States)

The crystal structure of a mixed aggregate containing lithiated (S)-N-ethyl-3-methyl-1-(triisopropylsilyloxy)butan-2-amine derived from (S)-valinol and cyclopentyllithium is determined by X-ray diffraction. The mixed aggregate adopts a ladder structure in the solid state. The ladder-type mixed aggregate is also the major species in a toluene-d8 solution containing an approximately 1:1 molar ratio of the lithiated chiral amide to cyclopentyllithium. A variety of NMR experiments including diffusion-ordered NMR spectroscopy (DOSY) with diffusion coefficient-formula (D-FW) weight correlation analyses and other one- and two-dimensional NMR techniques allowed us to characterize the complex in solution. Solution state structures of the mixed aggregates of n-butyl, sec-butyllithium, isopropyllithium with lithiated (S)-N-ethyl-3-methyl-1-(triisopropylsilyloxy)butan-2-amine are also reported. Identical dimeric, ladder-type, mixed aggregates are the major species at a stoichiometric ratio of 1:1 lithium chiral amide to alkyllithium in toluene-d8 solution for all of the different alkyllithium reagents. PMID:23980610

Su, Chicheung; Hopson, Russell; Williard, Paul G

2013-09-25

249

Effect of toluene on the hemolytic resistance of rat erythrocytes.  

Science.gov (United States)

The effect of toluene on rat erythrocyte hemolytic resistance was studied both in vitro and in vivo. In vitro, toluene at concentrations up to 1000 ppm showed a marked antihemolytic effect, the maximum being at 300 ppm. Above 1000 ppm, an increase in the hypotonic hemolysis was seen. The antihemolytic effect of toluene was temperature-dependent. Elevation of temperature diminished the ability of toluene to protect erythrocytes. In the in vivo experiments, when the rats breathed 2000 ppm of toluene in an inhalation chamber for 7 days and for 21 days (6 h/day), the antihemolytic effect of toluene was evident. Our results demonstrate that toluene, at moderate concentrations, increases the hemolytic resistance of rat erythrocytes in hypotonic media both in vitro and in inhalation exposures in vivo. PMID:6623518

Korpela, M; Vapaatalo, H; Tähti, H

1983-07-01

250

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

1994-01-01

251

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)

Full Text Available SciELO Colombia | Language: Spanish Abstract in portuguese 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

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

2012-01-01

252

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

253

Inquinamento outdoor - indoor da toluene e xileni  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

...

Moscato, U.; La Torre, G.; La Torre, F.; Pierangelini, A.; Ricciardi, G.

2003-01-01

254

Developmental toxicity of prenatal exposure to toluene  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Bowen, Scott E.; Hannigan, John H.

2006-01-01

255

Ethyl diazoacetate synthesis in flow  

Science.gov (United States)

Summary 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. PMID:24062847

Delville, Mariëlle M E; van Hest, Jan C M

2013-01-01

256

ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE  

Directory of Open Access Journals (Sweden)

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.

OLIVIA ANCA RUSU

2011-03-01

257

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

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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...

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

1989-01-01

258

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.

259

In vitro antiperoxidative, free radical scavenging and xanthine oxidase inhibitory potentials of ethyl acetate fraction of Saraca ashoka flowers.  

Science.gov (United States)

Saraca ashoka is a widely used medicinal herb claimed to cure many diseases. This study investigated the antiperoxidative, free radical scavenging and xanthine oxidase (XO) inhibitory potential of the ethyl acetate fraction of S. ashoka flowers (SAF) and compared it with standard compounds like gallic acid, ascorbic acid, butylated hydroxyl toluene and allopurinol. The ethyl acetate fraction of SAF exhibited free radical scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl radical and superoxide radical, along with hydroxyl radical scavenging activity. Lipid peroxidation inhibitory potential of SAF was studied using a linoleic acid emulsion system, which shows significant antioxidant potential. SAF also demonstrated significant XO (key enzyme linked to inflammation) inhibitory activity, which revealed its therapeutic potential as an antioxidant and XO inhibitor. HPLC profiling of the ethyl acetate fraction of SAF revealed that it contains ellagic acid as a major compound and thus the beneficial effects of this fraction may be due to the presence of this compound. PMID:21294042

Prathapan, A; Lijo Cherian, O; Nampoothiri, Suresh V; Mini, S; Raghu, K G

2011-02-01

260

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

Energy Technology Data Exchange (ETDEWEB)

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 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.

Sabourin, P.J.; Sun, J.D.; MacGregor, J.T.; Wehr, C.M.; Birnbaum, L.S.; Lucier, G.; Henderson, R.F. (Inhalation Toxicology Research Institute, Albuquerque, NM (USA))

1990-05-01

 
 
 
 
261

Biodegradation of benzene homologues in contaminated sediment of the East China Sea.  

Science.gov (United States)

This study focused on acclimating a microbial enrichment to biodegrade benzene, toluene, ethylbenzene and xylenes (BTEX) in a wide range of salinity. The enrichment degraded 120 mg/L toluene within 5d in the presence of 2M NaCl or 150 mg/L toluene within 7d in the presence of 1-1.5M NaCl. PCR-DGGE (polymerase chain reaction-denatured gradient gel electrophoresis) profiles demonstrated the dominant species in the enrichments distributed between five main phyla: Gammaproteobacteria, Sphingobacteriia, Prolixibacter, Flavobacteriia and Firmicutes. The Marinobacter, Prolixibacter, Balneola, Zunongwangia, Halobacillus were the dominant genus. PCR detection of genotypes involved in bacterial BETX degradation revealed that the degradation pathways contained all the known initial oxidative attack of BTEX by monooxygenase and dioxygenase. And the subsequent ring fission was catalysed by catechol 1,2-dioxygenase and catechol 2,3-dioxygenase. Nuclear magnetic resonance (NMR) spectroscopy profiles showed that the bacterial consortium adjusted the osmotic pressure by ectoine and hydroxyectoine as compatible solutes to acclimate the different salinity conditions. PMID:22989641

Li, Hui; Zhang, Qian; Wang, Xiao-Li; Ma, Xing-Yuan; Lin, Kuang-Fei; Liu, Yong-Di; Gu, Ji-Dong; Lu, Shu-Guang; Shi, Lei; Lu, Qiang; Shen, Ting-Ting

2012-11-01

262

Solution scattering studies of the hierarchical assembly of porphyrin trimers based on benzene triscarboxamide.  

Science.gov (United States)

The self-assembly of achiral and chiral porphyrin trimers based on benzene triscarboxamide in solution is studied with the help of NMR, FT-IR, UV-vis, and CD spectroscopy. These studies revealed that in apolar solvents the porphyrin trimers self-assembled in columnar stacks via a combination of hydrogen bonding and ?-? stacking interactions. While the critical aggregation constant is about 0.2 mM in chloroform, aggregation already occurs at micromolar concentrations in n-hexane. Small angle neutron scattering (SANS) studies in chloroform, toluene, and n-hexane confirmed aggregation of the trimers into columnar stacks. In chloroform and n-hexane, but not in toluene, the trimers gelated the solvent. In chloroform the stacks of the achiral trimer were found to contain on average about 70 molecules, while in toluene the stacks were much smaller and contained on average 7-9 molecules. In n-hexane the SANS studies revealed that the chiral trimer formed a gel with an average mesh size of the transient network of chains of approximately 90 nm, with chains being built up from effective cylindrical aggregates with an average length of 20 nm. PMID:25363515

van Hameren, Richard; van Buul, Arend M; Visser, Dirk; Heenan, Richard K; King, Stephen M; Rowan, Alan E; Nolte, Roeland J M; Pyckhout-Hintzen, Wim; Elemans, Johannes A A W; Feiters, Martin C

2014-12-28

263

Somatosensory evoked potentials in workers exposed to toluene and styrene.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Ste?tka?rova?, I.; Urban, P.; Procha?zka, B.; Luka?s, E.

1993-01-01

264

Antipyrine clearance during experimental and occupational exposure to toluene.  

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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...

Døssing, M.; Baelum, J.; Lundqvist, G. R.

1983-01-01

265

Toluene mediated oxidative stress and granulo-monocytopoiesis  

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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...

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

266

ADSORPTION OF TOLUENE ONTO BLEACHED EUCALYPTUS PULP TREATED WITH ULTRASOUND  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bleached kraft semichemical eucalyptus pulp was used as raw material to adsorb an organic compound, toluene, from aqueous solution. The pulp was sonicated with different powers and different times to obtain smaller cellulose fibers. The adsorption capacity for toluene of sonicated fibers and bleached eucalyptus pulp was measured by ultraviolet spectroscopy. The absorption capacity for toluene was increased considerably when cellulose nanofibres were obtained. The adsorption capacity of bleach...

Iñaki Urruzola,; Maria Ángeles Andrés,; Luis Serrano; Jalel Labidi

2012-01-01

267

21 CFR 573.420 - Ethyl cellulose.  

Science.gov (United States)

...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...

2010-04-01

268

21 CFR 172.868 - Ethyl cellulose.  

Science.gov (United States)

...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...

2010-04-01

269

The fate of benzene-oxide.  

Science.gov (United States)

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

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

2010-03-19

270

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

Energy Technology Data Exchange (ETDEWEB)

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).

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

1990-01-01

271

Anaerobic degradation of toluene by a denitrifying bacterium.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1991-01-01

272

Preferable solvatation of decane and benzene in 1-octanol- N, N-dimethylformamide mixed solvent  

Science.gov (United States)

Heat effects of the dissolution of decane and benzene in a model system of 1-octanol (OctOH)- N, N-dimethylformamide are measured at 298 and 318 K using a variable temperature calorimeter with an isotermic shell. The state of hydrocarbon molecules in the mixed solvent is studied using an extended coordination model and is compared to earlier data for ethyl acetate (EtOAc), DMF, OctOH, and tetramethyl hematoporphyrin (TMHP). It is shown that the polar carboxylic groups of porphyrin are preferably solvated by amide molecules due to stronger interaction with DMF, while nonpolar aliphatic groups are solvated by alcohol molecules. We conclude that a solvate shell of aromatic benzene is strongly enriched with DMF over the range of compositions, suggesting that the weakening of the preferable solvatation of porphyrin relative to EtOAc is due primarily to the influence of nonpolar substituents.

Kustov, A. V.; Smirnova, N. L.; Berezin, M. B.

2014-01-01

273

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.

274

Tricarbonylbis(tricyclohexylphosphine-?Pruthenium(0 toluene solvate  

Directory of Open Access Journals (Sweden)

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.

Andreas Nader

2008-11-01

275

Supercritical coal extraction with toluene-tetralin and toluene-ethanol mixtures  

Energy Technology Data Exchange (ETDEWEB)

Supercritical extraction of Banpoo coal using toluene-tetralin (70:30 v/v) and toluene-ethanol (90:10 v/v) was performed in semi-continuous apparatus at the temperature range 370-490{sup o}C and pressure up to 12.2 MPa. The preliminary study was to determine the important parameters such as temperature, pressure and time by using the 2-level factorial experimental design. The two factors, temperature and pressure were considered to have a significant effect on the coal conversion and liquid yield. Addition of tetralin to toluene increased the coal conversion and liquid yield by stabilization of radical fragments and inhibition of the radical recombination which included saturated hydrocarbons 7 wt%, aromatics 13 wt%, resins 16 wt% and asphaltenes 64 wt%. The yield of coal liquid at extraction condition of 490{sup o}C and 10 MPa with toluene-tetralin reached a maximum 33 wt% (in daf coal). The saturated hydrocarbon and aromatic fractions of coal liquid were also characterized by using GC/MS spectroscopy. The coal residue after extraction maintained most of its heating value and had lower sulfur content. 8 refs., 7 figs., 3 tabs.

S. Sangon; S. Ngamprasertsith; P. Prasassarakich [Chulalongkorn University, Bangkok (Thailand). Department of Chemical Technology, Faculty of Science

2003-07-01

276

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...may travel along the ground and be ignited by open...repeated or prolonged contact with the skin. High...Symptoms Direct skin contact with benzene may cause...Repeated or prolonged contact may result in drying...of benzene may have an initial stimulatory...

2010-07-01

277

Bio sensing Benzene in the refinery  

International Nuclear Information System (INIS)

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

278

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Lo?f, A.; Wigaeus Hjelm, E.; Colmsjo?, A.; Lundmark, B. O.; Norstro?m, A.; Sato, A.

1993-01-01

279

Steric guided change of electron transfer mechanism in benzene  

Science.gov (United States)

In fluorescence quenching study via electron transfer (ET), the quenching rate constant ( kq) values generally decrease with lowering of quencher concentration, since smaller concentration of quencher always leads to a red shift in the donor-acceptor (D-A) distance in ET [M. Tachiya, S. Murata, J. Phys. Chem. 96 (1992) 8441; S. Murata, M. Tachiya, J. Phys. Chem. 100 (1996) 4064; L. Burel, M. Mastafavi, S. Murata, M. Tachiya, J. Phys. Chem. A 103 (1999) 5882]. However, while doing a comparative study with different carbazole (CZ) derivatives-1,4-dicyanobenzene (DCB) systems in benzene (BZ), we observed a deviation from that normal behaviour. It was found that for all of them with lower quencher (DCB) concentration, kq values actually increase instead of the expected reduction. Exceptionally, for simple CZ (C 12H 9N) with decrease in concentration of DCB, kq values can even reach the order of energy transfer (10 11 s -1). Interestingly, it is not observed when toluene (TL) or xylene (XY) is used as solvent. To explain this unique observation, a sandwich type of molecular structure is predicted, where BZ sliding in between CZ and DCB brings them closer enough, imparting more through bond character to CZ-DCB interaction and hence a higher rate of ET ( kq) is observed [L. Burel, M. Mastafavi, S. Murata, M. Tachiya, J. Phys. Chem. A. 103 (1999) 5882].

Chatterjee, Suchandra; Basu, Samita; Ghosh, Nandita; Chakrabarty, Manas

2005-06-01

280

Solubility of phosphonium ionic liquid in alcohols, benzene, and alkylbenzenes.  

Science.gov (United States)

The (solid + liquid) phase equilibria and (liquid + liquid) phase equilibria of binary mixtures containing quaternary phosphonium salt-tetrabutylphosphonium methanesulfonate and alcohols or alkylbenzenes were investigated. The systems {[(CH(3)CH(2)CH(2)CH(2))4P][CH(3)SO(3)] + 1-butanol, or 1-hexanol, 1-octanol, 1-decanol, or 1-dodecanol} and {[(CH(3)CH(2)CH(2)CH(2))4P][CH(3)SO(3)] + benzene, or toluene, ethylbenzene, or propylbenzene} have been measured by a dynamic method at a wide range of temperatures from 220 to 386 K. Solid-liquid equilibria with immiscibility in the liquid phase were detected with the aromatic hydrocarbons ethylbenzene and propylbenzene. The basic thermodynamic properties of pure ionic liquid--the melting point, enthalpy of fusion, enthalpy of solid-solid-phase transition, and glass transition--have been determined by differential scanning calorimetry. The experimental data of systems with alcohols were correlated by means of the UNIQUAC ASM and NRTL1 equations and of systems with alkylbenzenes with Wilson and NRTL equations utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular system and the particular equation used. PMID:17391024

Doma?ska, Urszula; Casás, Lidia M

2007-04-26

 
 
 
 
281

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

282

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, typic...

Daniel, Cimi A.; Sugunan, S.

2013-01-01

283

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 general...

Heidari, H.; Shahtaheri, S. J.; Alimohammadi, M.; Rahimi-froshani, A.; Golbabaei, F.

2012-01-01

284

Redetermination of ethyl­ene­diammonium bis­(p-methyl­benzene­sulfonate) monohydrate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the asymmetric unit of the title compound, C2H10N22+·2C7H7O3S?·H2O, there are two independent 4-methylbenzenesulfonate anions, one ethylenediammonium cation and a water molecule. The present redetermination was carried out to improve the treatment of disorder, which was not refined in the previous study [Ahn & Kim (1985). J. Korean Chem. Soc. 29, 335–340]. One of the sulfonate groups is disordered over two positions, with site-occupancy factors of 0.588?(14)...

Chao Shen-Tu; Lin-Lin Ma; Wei Xu; Ying Chen; Zhi-Min Jin

2007-01-01

285

Structure of ethyl phenyl selenone.  

Science.gov (United States)

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

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

1993-03-15

286

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

Science.gov (United States)

...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...

2010-08-27

287

Anaerobic Benzene Degradation in Petroleum-Contaminated Aquifer Sediments after Inoculation with a Benzene-Oxidizing Enrichment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sediments from the sulfate-reduction zone of a petroleum-contaminated aquifer, in which benzene persisted, were inoculated with a benzene-oxidizing, sulfate-reducing enrichment from aquatic sediments. Benzene was degraded, with apparent growth of the benzene-degrading population over time. These results suggest that the lack of benzene degradation in the sulfate-reduction zones of some aquifers may result from the failure of the appropriate benzene-degrading sulfate reducers to colonize the a...

Weiner, Jonathan M.; Lovley, Derek R.

1998-01-01

288

Organic aerosol formation during the atmospheric degradation of toluene.  

Science.gov (United States)

Organic aerosol formation during the atmospheric oxidation of toluene was investigated using smog chamber systems. Toluene oxidation was initiated by the UV irradiation of either toluene/air/NOx or toluene/air/CH3ONO/NO mixtures. Aerosol formation was monitored using scanning mobility particle sizers and toluene loss was monitored by in-situ FTIR spectroscopy or GC-FID techniques. The experimental results show that the reaction of OH radicals, NO3 radicals and/or ozone with the first generation products of toluene oxidation are sources of organic aerosol during the atmospheric oxidation of toluene. The aerosol results fall into two groups, aerosol formed in the absence and presence of ozone. An analytical expression for aerosol formation is developed and values are obtained for the yield of the aerosol species. In the absence of ozone the aerosol yield, defined as aerosol formed per unit toluene consumed once a threshold for aerosol formation has been exceeded, is 0.075 +/- 0.004. In the presence of ozone the aerosol yield is 0.108 +/- 0.004. This work provides experimental evidence and a simple theory confirming the formation of aerosol from secondary reactions. PMID:11348067

Hurley, M D; Sokolov, O; Wallington, T J; Takekawa, H; Karasawa, M; Klotz, B; Barnes, I; Becker, K H

2001-04-01

289

Active efflux of toluene in a solvent-resistant bacterium.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Isken, S.; Bont, J. A.

1996-01-01

290

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 ...

291

Reactions of 9-alkyl-3-aminocarbazoles with ethyl-3-oxo-butanoate and identification of the products obtained.  

Science.gov (United States)

The reactions in benzene of 9-alkyl-3-aminocarbazoles with ethyl-3-oxobutanoate yielded ethyl-3-[(9-alkyl-9H-carbazol-3-yl)amino]but-2-enoate condensation products or N-(9-ethyl-9H-carbazol-3-yl)-3-oxobutanamide acylation products. The condensation products were cyclized to the corresponding 4,7-dihydro-pyrido[2,3-c]-carbazol-1-ones upon heating in mineral oil at 240-250 degrees C. The structures of the synthesized compounds were investigated by IR, mass spectrometry, (1)H- and (13)C-NMR spectroscopy and MM2 molecular mechanics and AM1 semi-empirical quantum mechanical methods. PMID:17962748

Sapijanskaite, Birute; Mickevicius, Ytautas; Mikulskiene, Gema

2006-01-01

292

Ethyl 2-[3-(4-nitro­benzo­yl)thio­ureido]benzoate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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......

Sohail Saeed; Naghmana Rashid; Wing-Tak Wong

2010-01-01

293

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Yoshinobu Ishikawa; Nanako Yoshida

2014-01-01

294

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

Science.gov (United States)

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 <5% to 80%, and the intensity of the bands of -OH, -C=O and C-OH from SOA samples also greatly increases with RH. In 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.

Jia, L.; Xu, Y.

2012-12-01

295

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

296

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)

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.

Cuiqin Wu

2006-12-01

297

40 CFR Appendix Vii to Part 261 - Basis for Listing Hazardous Waste  

Science.gov (United States)

...nitrobenzene. F005 Toluene, methyl ethyl ketone, carbon disulfide, isobutanol, pyridine, 2-ethoxyethanol, benzene, 2-nitropropane... Ethylene thiourea. K126 Ethylene thiourea. K131 Dimethyl sulfate, methyl bromide. K132 Methyl bromide....

2010-07-01

298

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-11-15

299

Crystal structure of (±)-(4RS,5RS,7SR)-4-[(1RS,2RS,3RS,6RS)-3-benzo­yloxy-2-(2-hy­droxy­ethyl)-6-meth­oxy­meth­oxy-2-methyl­cyclo­hex­yl]-8,10,10-trimethyl-2-oxo-1,3-dioxa­spiro­[4.5]dec-8-en-7-yl benzoate benzene monosolvate  

Science.gov (United States)

In the title compound, C36H44O10·C6H6, the dioxolane ring adopts an envelope conformation with the C atom bonded to the H atom as the flap, while the cyclo­hexene and cyclo­hexane rings are in half-chair and chair conformations, respectively. In the crystal, a pair of O—H?O hydrogen bonds with an R 2 2(26) graph-set motif connect the benzoate mol­ecules into an inversion dimer. The dimers are linked by a weak C—H?O inter­action into a tape structure along [01-1]. The benzene mol­ecule links the tapes through C—H?O and C—H?? inter­actions, forming a sheet parallel to (100).

Oishi, Takeshi; Yamaguchi, Yuu; Fukaya, Keisuke; Sugai, Tomoya; Watanabe, Ami; Sato, Takaaki; Chida, Noritaka

2015-01-01

300

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...of physical signs relating to blood disorders: (B) A complete blood count...concentrations, may result in various blood disorders, ranging from anemia to leukemia...irreversible, fatal disease. Many blood disorders associated with benzene...

2010-07-01

 
 
 
 
301

Radiocarbon dating methods using benzene liquid scintillation  

International Nuclear Information System (INIS)

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

302

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...to repeated or prolonged contact with the skin. High concentration...III. Signs and Symptoms Direct skin contact with benzene may cause erythema...be performed by portable direct reading instruments, real-time continuous...

2010-07-01

303

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...life. (3) Respirator selection. (i) Employers must...locations remote from the site at which benzene is handled...disposing in a sanitary landfill; (b) if small quantities...circumvented by proper selection of HPLC...

2010-07-01

304

Recommended sublimation pressure and enthalpy of benzene  

International Nuclear Information System (INIS)

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

305

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...repeated or prolonged contact with the skin...and Symptoms Direct skin contact with benzene may...or refer the patient if repeat tests...relatively few patients have been studied...performed by portable direct reading...

2010-07-01

306

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...swallowed and the patient is conscious...or skin/eye contact) under emergency...and to record the results obtained. When...Symptoms Direct skin contact with benzene may...Repeated or prolonged contact may result in...

2010-07-01

307

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...Guidelines, Benzene I. Physical and Chemical Data A. Substance identification. 1. Synonyms: Benzol, benzole, coal naphtha, cyclohexatriene, phene, phenyl hydride, pyrobenzol. (Benzin, petroleum benzin and Benzine do not contain...

2010-07-01

308

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

Science.gov (United States)

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

Zborowski, Krzysztof K.

2014-05-01

309

Benzene-derived carbon nanothreads  

Science.gov (United States)

Low-dimensional carbon nanomaterials such as fullerenes, nanotubes, graphene and diamondoids have extraordinary physical and chemical properties. Compression-induced polymerization of aromatic molecules could provide a viable synthetic route to ordered carbon nanomaterials, but despite almost a century of study this approach has produced only amorphous products. Here we report recovery to ambient pressure of macroscopic quantities of a crystalline one- dimensional sp3 carbon nanomaterial formed by high-pressure solid-state reaction of benzene. X-ray and neutron diffraction, Raman spectroscopy, solid-state NMR, transmission electron microscopy and first-principles calculations reveal close- packed bundles of subnanometre-diameter sp3-bonded carbon threads capped with hydrogen, crystalline in two dimensions and short-range ordered in the third. These nanothreads promise extraordinary properties such as strength and stiffness higher than that of sp2 carbon nanotubes or conven tional high-strength polymers. They may be the first member of a new class of ordered sp3 nanomaterials synthesized by kinetic control of high-pressure solid-state reactions.

Fitzgibbons, Thomas C.; Guthrie, Malcolm; Xu, En-Shi; Crespi, Vincent H.; Davidowski, Stephen K.; Cody, George D.; Alem, Nasim; Badding, John V.

2015-01-01

310

Photoionization spectrum of liquid benzene  

Energy Technology Data Exchange (ETDEWEB)

The photocurrent from neat liquid benzene has been studied for excitation energies from threshold to 10.3 eV and for externally applied electric fields from 1 to 50 kV/cm. Using a power law fit to the energy dependence of the threshold current, an onset of [epsilon][sub t] = 7.65 [+-] 0.1 eV has been obtained. The field dependence was fit to an exponential radial probability density for thermalized ion-pair separation distances with an average separation distance of [r] = 23 [+-] 2 A at an excitation energy, [epsilon] of 8.86 eV (1.2 eV above threshold). Photocurrent was too weak to establish a dependence of [r] on excitation energy. The quantum yield for photocurrent at 8.86 eV was determined by comparison with the photocurrent from TMPD in 2,2,4-trimethylpentane (isooctane) to be 6.5 [times] 10[sup [minus]4] at zero field. From this, the intrinsic molecular ionization probability at [epsilon] = 8.86 eV was determined to be 0.6 [+-] 0.3. 30 refs., 5 figs.

Saik, V. O.; Lipsky, S. (Univ. of Minnesota, Minneapolis, MN (United States))

1994-11-17

311

Formation of benzene in the interstellar medium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block—the aromatic benzene molecule—has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethyn...

Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.

2011-01-01

312

Acute behavioural comparisons of toluene and ethanol in human subjects.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1991-01-01

313

Studies of toluene adsorption, migration and persistence in soil by means of 14C labelled compound  

International Nuclear Information System (INIS)

The adsorption, migration and persistence of toluene in soils were studied using 14C labelled compound. The results show that the adsorption efficiencies of toluene in various soils are not high. Toluene is liable to transport in soils, but the persistence half-life of toluene in soil is rather long

314

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

315

Psychomotor performance and subjective symptoms at low level toluene exposure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objectives: Possible effects of long term occupational exposure to toluene below the level of 100 ppm on psychomotor performance and subjective symptoms were investigated in a cross sectional approach.

Zupanic, M.; Demes, P.; Seeber, A.

2002-01-01

316

Sudden death from toluene intoxication: a case report and review of literature.  

Science.gov (United States)

Toluene is an aromatic hydrocarbon (C7H8) found in gasoline, acrylic paints, varnishes, lacquers, paint thinners, adhesives, and shoe polish. Toluene toxicity can occur from unintentional or deliberate inhalation of fumes, ingestion, or transdermal absorption. Unintentional exposure to high concentrations of toluene results in severe toluene intoxication. This is a report of toluene poisoning in a middle-age man found dead at home after varnish application by spray. There was no obvious external and internal cause of death. The blood test revealed the presence of toluene. The cause of death was diagnosed as cardiopulmonary failure caused by toluene, which is a rare case report in Thailand. PMID:24164003

Prayulsatien, Weerapong

2013-09-01

317

Acute toluene effects on neurotransmission in the central nervous system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this thesis was to develop a method to study the effects of toluene in thecentral nervous system of the rat. Microdialysis on awake rats was used to studytoluene's effects on the transmission of dopamine, acetylcholine, glutamate andaspartate in the striatum, and on GABA in the striatum, the cerebellum and the globuspallidus. A comparison between toluene's and halothane's effects on GABAneurotransmission in the cerebellum was also made. By recording eye movements, theacute effects ...

Stenga?rd, Karl

1996-01-01

318

Adsorption of toluene on carbon nanofibers prepared by electrospinning.  

Science.gov (United States)

This paper reports the novel results of activated carbon nanofibers (ACNF) used to improve the toluene adsorption capacity. The ACNF was prepared by stabilization, carbonization and activation after electrospinning the polymer solution of polyacrylonitrile (PAN) in N, N-dimethylformamide. The average diameter of the ACNF was approximately 300 nm, ranging from 200 to 500 nm. The toluene adsorption capacity of ACNF10 activated at 1000 degrees C increased to 65 g-toluene/100 g-ACNF. This was attributed to the high specific surface area (1403 m(2)/g), large micropore volume (0.505 cm(3)/g), and narrow average pore diameter (6.0 A). The oxygen to carbon ratio (O/C ratio) in ACNF10 was 1.8%. This O/C ratio appears to induce a higher toluene adsorption capacity, which originates from a non-polar interaction between the ACNF surface and toluene. In conclusion, the electrospun ACNF prepared in this study promotes the adsorption of toluene through the high specific surface area, large pore volume, narrow pore diameter and low O/C ratio. PMID:18262599

Oh, Gil-Young; Ju, Young-Wan; Kim, Mi-Young; Jung, Hong-Ryun; Kim, Hyung Jin; Lee, Wan-Jin

2008-04-15

319

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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)....

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

1992-01-01

320

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Wang, R. S.; Nakajima, T.

1992-01-01

 
 
 
 
321

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1997-01-01

322

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

Science.gov (United States)

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

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

2014-08-01

323

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

1991-01-01

324

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

Science.gov (United States)

Replacement reactions of toluene-3,4-dithiolatoarsenic(III) chloride with oxygen and sulphur donor ligands like benzoic acid, thiobenzoic acid, anhydrous sodium acetate, thioacetic acid, phenol, thiophenol, sodium salicylate and thio glycolic acid in 1:1 molar ratio as well as disodium oxalate in 2:1 molar ratio in refluxing anhydrous benzene yielded toluene-3,4-dithiolatoarsenic(III) mono oxo or thio carboxylic or phenolic derivatives of the general formula SC6H3(CH3)SAsR {where R = OOCC6H5, SOCC6H5, OOCCH3, SOCCH3, OC6H5, SC6H5, OOCC6H4(OH), SCH2COOH} and SC6H3(CH3)SAsOOC-COOAsS(CH3)C6H3S. These synthesized derivatives are yellow, yellow-brown solids/ liquids and are soluble in common organic solvents like benzene, chloroform, dichloromethane, dimethyl formamide, dimethyl sulphoxide etc. These derivatives have been characterized by melting point determination, molecular weight determination, elemental analysis (C, H, S and As), spectral {UV, IR, NMR (1H and 13C), ESI-Mass, SEM and powder X-ray diffraction} and thermal (TGA, DTA and DSC) studies. Some of these compounds have been screened for their antimicrobial activities using the disc diffusion method. These derivatives have shown good activity as antibacterial and antifungal agents on some selected bacterial and fungal strains, which increased on increasing the concentration. Chloroamphenicol and terbinafin were used as standards for the comparison.

Chauhan, H. P. S.; Bhatiya, Sumit

2012-11-01

325

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

Directory of Open Access Journals (Sweden)

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.

Moritz Schubert

2014-09-01

326

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

Science.gov (United States)

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

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

327

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)

328

Formation of alkylaromatic hydrocarbons with interaction between paraffins and benzene in an H-mordenite  

Energy Technology Data Exchange (ETDEWEB)

Alkylation of benzene by products of transformation of n-pentane and n-hexane in dealuminated H-mordenite (SiO2 to A12O3 of 80) in a medium of hydrogen at a pressure of 3.5 megapascals, a temperature of 300 to 380C in a through type installation is studied. The composition of the alkylaromatic hydrocarbons (UV), formed with interaction between n-pentane and n-hexane and benzene in a high silicon content H-mordenite is studied at a temperature of 300 to 380C and a pressure of 3.5 megapascals. It is established that with a minimal depth of alkylation, the primary formation of ethylbenzene and o-xylene is observed. Toluene and m-xylene and n-xylene are formed as a result of secondary reactions. A mechanism is proposed for disproportionation of the C5H6 paraffins in zeolites with basic formation of the corresponding C3 to C4 and C4 to C5 products, which provides for a stage of intermolecular transfer of the C2 fragments.

Kogan, S.B.; Bursian, N.R.; Karagan, V.K.

1984-01-01

329

Hydrogen bonding in (substituted benzene)·(water)n clusters with n?4  

International Nuclear Information System (INIS)

Infrared ion-depletion spectroscopy, a double resonance method combining vibrational predissociation with resonant two-photon ionization (R2PI) spectroscopy, has been applied to study mixed clusters of the type (substituted benzene)·(H2O)n with n?4. The UV chromophores were p-difluorobenzene, fluorobenzene, benzene, toluene, p-xylene and anisole. From the IR depletion spectra in the region of the OH stretching vibrations it could be shown that the water molecules are attached as subclusters to the chromophores. Size and configuration of the subclusters could be deduced from the IR depletion spectra. In the anisole·(H2O)1and2 complexes the water clusters form an ordinary hydrogen bond to the oxygen atom of the methoxy group. In all other mixed complexes a ?-hydrogen bond is formed between one of the free OH groups of a water subcluster and the ?-system of the chromophore. According to the strength of this interaction the frequency of the respective absorption band exhibits a characteristic red-shift which could be related to the total atomic charges in the aromatic ring. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

330

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

International Nuclear Information System (INIS)

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

331

Spectrophotometric determination of benzene in ethanol.  

Science.gov (United States)

A rapid, simple spectrophotometric method for the detection and determination of benzene in ethanol is described. Thus, using 1 cm cuvettes and applying the first and/or the second derivative methods, benzene can be determined in ethanol over the concentration range of 5-25 p.p.m. with a CV% less than 1% and with a detection limit of 2 p.p.m. This is considered to be an improvement over the method currently given in the British Pharmacopoeia. PMID:1856248

Barary, M H; Sabry, S M; Wahbi, A A

1991-04-01

332

S-p -Toluylmercapturic acid in the urine of workers exposed to toluene: a new biomarker for toluene exposure  

Energy Technology Data Exchange (ETDEWEB)

A mercapturic acid attached to the aromatic ring of toluene was for the first time detected in human urine as a metabolite of toluene. Since the metabolism of toluene is usually considered to take place at the side-chain, this gives, besides the biosynthesis of cresols, a further hint of a metabolic conversion of the aromatic system. We examined a group of 33 workers occupationally exposed to toluene, determining the concentrations of toluene in ambient air and in whole blood, o-cresol and hippuric acid in urine and p-toluylmercapturic acid (p-TMA) in urine. All blood and urine samples were collected post-shift. The renal excretion of S-p-toluylmercapturic acid showed highly significant correlations with established parameters of a biological monitoring of toluene. The median ambient air concentration was 63 ppm, ranging from 13 to 151 ppm, the median concentration of toluene in whole blood was 804 {mu}g/l, corresponding to median urinary concentrations for o-cresol of 2.3 mg/l, hippuric acid of 2.3 g/l and p-TMA of 20.4 {mu}g/l. p-TMA was not detectable in urine samples of a control group of 10 non-exposed persons. Both the German Biological Tolerance Values (BAT-values) for toluene in blood (1000 {mu}g/l) and o-cresol in urine (3 mg/l) correspond to a mean p-TMA elimination of {proportional_to}50 g/l, and thus are in agreement with each other. According to our results p-TMA reflects internal toluene exposure diagnostically sensitive and specifical. With the developed analytical procedure we determined a median benzylmercapturic acid (BMA) concentration of 190 {mu}g/l in the urine samples of the toluene exposed persons. We also determined a median BMA concentration of 30 {mu}g/l in the control samples of non-exposed persons. However, these results are preliminary and require further confirmation as the reliability of the method was determined only for p-TMA. (orig.) With 3 figs., 1 tab., 24 refs.

Angerer, J.; Schildbach, M.; Kraemer, A. [Friedrich-Alexander-University of Erlangen-Nuernberg, Institute and Clinic of Occupational-, Social- and Environmental Medicine, Erlangen (Germany)

1998-01-01

333

A Nonlinear Optical Experiment: Stimulated Raman Scattering in Benzene and Deuterated Benzene  

Science.gov (United States)

A nonlinear optical experiment is presented that utilizes a doubled Nd:YAG laser to produce stimulated Raman scattering (SRS) in benzene and deuterated benzene. A sampling arrangement is described that results in strong stimulated Raman emission involving symmetric CC and CH(CD) stretching modes in both C6H6 and C6D6. The wavelengths of the coherent beams are easily measured with a simple transmission grating and meter stick. Observations of both collinear and conical stimulated Raman beams are made and the reasons for these discussed. The measured frequencies permit calculation of CC and CH force constants in benzene.

Melin, Stéphanie; Nibler, Joseph W.

2003-10-01

334

On the mechanism of the dehydroaromatization of hexane to benzene by an iridium pincer catalyst.  

Science.gov (United States)

The developments in the area of transition-metal pincer complexes have opened up new avenues for conversion of saturated hydrocarbons to more useful aromatic compounds under homogeneous reaction conditions. In the backdrop of an interesting series of conversions of unbranched alkanes to benzene, toluene, and xylene (known as the BTX family aromatics) reported by Goldman and co-workers (Nature Chem. 2011, 3, 167), we herein present a comprehensive mechanistic picture obtained by using density functional computations. The reaction involves an iridium-PCP-pincer-catalyzed dehydroaromatization of hexane to benzene (in which PCP=?(3) -C6 H3 (iPrP)2 -1,3) by using tert-butylethylene (TBE) as a sacrificial acceptor. The most energetically preferred pathway for a sequence of dehydrogenations is identified to begin with a terminal C?H bond activation of n-hexane leading to the formation of hex-1-ene. Although the initial dehydrogenation of n-hexane was found to be endergonic, the accompanying exoergic hydrogenation of TBE to tert-butylethane (TBA) compensates the energetics to keep the catalytic cycle efficient. Subsequent dehydrogenations provide a hexa-1,3-diene and then a hexa-1,3,5-triene. The pincer bound triene is identified to undergo cyclization to furnish cyclohexadiene. Eventually, dehydrogenation of cyclohexa-1,3-diene offers benzene. In the most preferred pathway, the Gibbs free energy barrier for cyclization leading to the formation of cyclohexa-1,3-diene is found to exhibit the highest barrier (21.7?kcal?mol(-1) ). PMID:23364899

Thawani, Akanksha; Rajeev, Ramanan; Sunoj, Raghavan B

2013-03-18

335

Toluene in sewage and sludge in wastewater treatment plants.  

Science.gov (United States)

Toluene is a compound that often occurs in municipal wastewater ranging from detectable levels up to 237 ?g/L. Before the year 2000, the presence of the aromatic hydrocarbons was assigned only to external sources. The Enhanced Biological Nutrients Removal Processes (EBNRP) work according to many different schemes and technologies. For high-efficiency biological denitrification and dephosphatation processes, the presence of volatile fatty acids (VFAs) in sewage is required. VFAs are the main product of organic matter hydrolysis from sewage sludge. However, no attention has been given to other products of the process. It has been found that in parallel to VFA production, toluene formation occurred. The formation of toluene in municipal anaerobic sludge digestion processes was investigated. Experiments were performed on a laboratory scale using sludge from primary and secondary settling tanks of municipal treatment plants. The concentration of toluene in the digested sludge from primary settling tanks was found to be about 42,000 ?g/L. The digested sludge supernatant liquor returned to the biological dephosphatation and denitrification processes for sewage enrichment can contain up to 16,500 ?g/L of toluene. PMID:24434978

Mrowiec, Bozena

2014-01-01

336

Influence of organobentonite structure on toluene adsorption from water solution  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Nuria, Vidal; Cristina, Volzone.

2012-12-01

337

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

338

Hydrogen Absorption at Room Temperature in Nanoscale Titanium Benzene Complexes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2009-01-01

339

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...changes in medicinal drug use, and the appearance...of variations in the susceptibility to benzene morbidity...allergies and some drugs may raise the white...A constellation or pattern of abnormalities in...cell indices, such a pattern is more likely to...

2010-07-01

340

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...the eosinophil count is less specific but also may be suspicious...and of alkaline phosphatase activity in peripheral granulocytes...and 5 drops of concentrated nitric acid. The benzene is converted...once, the percentage of the specific compound that is removed...

2010-07-01

 
 
 
 
341

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...15-minute period. 2. Dermal: Eye contact shall be prevented and skin...inhale it, or if it comes in contact with your skin or eyes...exposed to benzene (either by ingestion, inhalation, or skin/eye contact) under emergency...

2010-07-01

342

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...min. 1. Principle of the Method...front of the first section of charcoal and broken open. The glass wool...charcoal in the first (larger) section...area. 7. Calculations. Benzene air...from a number of sources was analyzed...volume. 1. Principle of the...

2010-07-01

343

Stark effect in the benzene dimer.  

Science.gov (United States)

Ab initio calculations of the six-dimensional intermolecular potential have shown the benzene dimer to be an asymmetric top molecule at equilibrium with one benzene moiety forming the "stem" and the other a "tilted cap" in a T-shaped structure. Internal rotation of the cap about its C6 axis is essentially free; the barriers for cap tilting and for internal rotation of the stem about its C6 axis are hindered by successively higher barriers. In previous work we have validated these theoretical results using Fourier transform microwave spectroscopy in conjunction with dynamics calculations. We have also measured the Stark effect, and despite the fact that the equilibrium structure is that of an asymmetric top, the assigned transitions involving K = 0 exhibit a second-order Stark effect whereas those involving K = 1 exhibit a first-order Stark effect. This is typical for a symmetric-top molecule, but anomalous for an asymmetric-top molecule. We use symmetry arguments to explain how this asymmetric-top molecule can have a first-order Stark effect in certain states that have excitation of cap internal rotation. Cap internal rotation is essentially the twisting of the monomers relative to each other about the intermolecular axis, and such torsional motion occurs in other asymmetric top dimers such as benzene-CO and benzene-H2O. These latter dimers will also have levels that exhibit a first-order Stark effect, which we can explain using our symmetry arguments. PMID:24102247

Schnell, Melanie; Bunker, P R; von Helden, Gert; Grabow, Jens-Uwe; Meijer, Gerard; van der Avoird, Ad

2013-12-19

344

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...appropriate to prevent eye contact and limit dermal...provided by the employer at no cost to the...solvents containing greater than 0.1 percent...benzene. (ii) The employer shall assure that...test is equal to or greater than 75 mg phenol/L of urine, the employer shall provide...

2010-07-01

345

29 CFR 1910.1028 - Benzene.  

Science.gov (United States)

...regarding any new exposure to potential marrow toxins, changes in medicinal drug use, and the...exposure to benzene or any other hematologic toxins. (iii) The employer shall maintain...aprons, etc.) over any parts of your body that could be exposed to liquid...

2010-07-01

346

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

Directory of Open Access Journals (Sweden)

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.

Zhengjun Zhang

2011-12-01

347

46 CFR 197.565 - Notifying personnel of benzene hazards.  

Science.gov (United States)

...sheet. A material safety data sheet (MSDS) addressing benzene must be made available...involved in the benzene operation. The MSDS must describe the physical and chemical...appendices A and B of this subpart or a MSDS on benzene meeting the requirements...

2010-10-01

348

Sizes of vanadyl petroporphyrins and asphaltene aggregates in toluene  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-01

349

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] 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.

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

2003-05-01

350

Degradation of waste gas containing toluene in an airlift bioreactor.  

Science.gov (United States)

Suspension microorganisms in an internal-loop airlift bioreactor were utilized to treat waste gas containing toluene. The working volume of the reactor was 35 L, and the biomass concentration was 3 kg/m3. The gas pollutant flowed into the reactor from the bottom; it then transferred from the gas phase to the liquid phase and was degraded by the microorganisms suspended in the liquid phase. The microorganisms were able to degrade 50-90% of the inlet toluene when its concentration was from 0.5 to 10 g/m3, and the superficial gas velocity ranged from 0.15 to 1.23 cm/s. A comprehensive mathematical model was also developed to describe the overall degradation process of toluene in the internal-loop airlift bioreactor. The overall degradation process included gas flow, gas-liquid mass transfer, flow and dispersion of the liquid phase, and microbial kinetics. The hydrodynamic properties including the gas and liquid superficial velocities, the gas holdup, the volumetric mass transfer coefficients of toluene and oxygen, and the microbial kinetics were obtained for this model. The substrate inhibition theory was used to simulate the microorganism growth kinetics, and its kinetic constants were obtained experimentally. The penetration theory was used to predict the volumetric mass transfer coefficient. And the drift-flux theory was used to predict the hydrodynamic properties in each section (riser, gas-liquid separator, downcomer, and bottom) of the airlift bioreactor. The concentration distributions of toluene and oxygen in the airlift bioreactor and the removal efficiency of toluene predicted by the mathematical model agreed well with the experimental data. PMID:15112834

Lo, Cheng-Shing; Hwang, Shyh-Jye

2004-04-01

351

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-04-15

352

4-(2-Ethyl­phen­yl)-1-(2-oxoindolin-3-yl­idene)thio­semicarbazide  

Science.gov (United States)

The title compound, C17H16N4OS, is stabilized in the form of a two-dimensional polymeric network due to inter­molecular N—H?S and N—H?O hydrogen bonds. An intra­molecular N—H?N hydrogen bond forms an S(5) ring, whereas inter­actions of the N—H?O and C—H?S types complete S(6) ring motifs. ?–? inter­actions with a centroid–centroid distance of 3.6514?(10)?Å are found between the ethyl-substituted benzene ring and the heterocyclic ring of the isatin derivative. PMID:21587842

Pervez, Humayun; Yaqub, Muhammad; Ramzan, Muhammad; Tahir, M. Nawaz; Iqbal, Mohammad S.

2010-01-01

353

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

Directory of Open Access Journals (Sweden)

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.

Waseeq Ahmad Siddiqui

2008-03-01

354

Transformations of toluene radical cation in ZSM-5 and Silicalite  

Energy Technology Data Exchange (ETDEWEB)

Toluene radical cations produced by {gamma} irradiation at 77 K in ZSM-5 and Silicalite (isomorphous with ZSM-5 but nonpolar) undergo a reversible transformation to the norbornadiene radical cation at temperatures {le}150K. The transformation occurs to a greater extent in the more polar zeolite (ZSM-5). The substrate concentration plays an important role. Toluene radical cations undergo ion-molecule reactions to give benzyl radicals at low substrate loading at temperatures >200 K. At higher concentration, different adsorption sites become populated which allow the transformation to norbornadiene radical cation to take place.

Barnabas, M.V.; Werst, D.W.; Trifunac, A.D.

1992-11-25

355

Synergistic effect of catalyst for oxidation removal of toluene  

International Nuclear Information System (INIS)

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

356

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)

357

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

358

PREFRACTIONATION OF HIGH BENZENE PRECURSORS’ FEED FOR HYBRID REFORMER UNIT  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

359

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

International Nuclear Information System (INIS)

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

360

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-10-01

 
 
 
 
361

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1986-01-01

362

Isolation and Characterization of a Novel Toluene-Degrading Bacterium Exhibiting Potential Application in Bioremediation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: Toluene is a cyclic aromatic hydrocarbon which is widely used as an industrial feedstock and as a solvent. It is one of the major parts of pollution in oil-contaminated environments..Objectives: The main aim of this study was to isolate and characterize a bacterium with high potential application in toluene bioremediation..Materials and Methods: To isolate a toluene-degrading bacterium, several seawater and wastewater samples were added to toluene-containing basal salt media (BSM)...

Giti Emtiazi1,; Afrouzossadat Hosseini Abari; Seyed Mahdi Ghasemi; Rasoul Roghanian

2013-01-01

363

Abuse Pattern of Toluene Exposure Alters Mouse Behavior in a Waiting-for-Reward Operant Task  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Inhaling solvents for recreational purposes continues to be a world-wide public health concern. Toluene, a volatile solvent in many abused products, adversely affects the central nervous system. However, the long-term neurobehavioral effects of exposure to high-concentration, binge patterns typical of toluene abuse remain understudied. We studied the behavioral effects of repeated toluene exposure on cognitive function following binge toluene exposure on behavioral impulse control in Swiss We...

Bowen, Scott E.; Mcdonald, Phillip

2009-01-01

364

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1993-01-01

365

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1983-01-01

366

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 appropria...

Ogawa Masanori; Sasahara Teppei

2012-01-01

367

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

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

1995-01-01

368

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2004-01-01

369

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1996-01-01

370

Interactions between Asphaltenes and Water in Solutions in Toluene  

DEFF Research Database (Denmark)

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.

Khvostichenko, Daria; Andersen, Simon Ivar

2008-01-01

371

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...

372

Identification of toluene degraders in a methanogenic enrichment culture.  

Science.gov (United States)

Methanogenic biodegradation involves the cooperative metabolism of syntrophic bacteria that catalyse the initial attack and subsequent degradation of hydrocarbons, and methanogens that convert intermediates such as hydrogen and carbon dioxide, formate, and/or acetate to methane. The identity of syntrophic microbes and the nature of their interactions with other syntrophs and methanogens are not well understood. Furthermore, it is difficult to isolate the organisms responsible for the initial activation and subsequent degradation of hydrocarbon substrates under methanogenic conditions due to the thermodynamic relationships that exist among microbes in methanogenic communities. We used time-resolved RNA stable isotope probing and RT-qPCR to identify the organisms involved in the initial attack on toluene and subsequent degradation reactions in a highly enriched toluene-degrading methanogenic culture. Our results reveal the importance of a Desulfosporosinus sp. in anaerobic toluene activation in the culture. Other organisms that appear to play roles in toluene degradation include Syntrophaceae, Desulfovibrionales and Chloroflexi. The high bacterial diversity observed in this culture and the extensive labelling of different phylogenetic groups over the course of the stable isotope probing experiment highlight the complexity of the relationships that exist in methanogenic ecosystems. PMID:24910080

Fowler, S Jane; Gutierrez-Zamora, Maria-Luisa; Manefield, Mike; Gieg, Lisa M

2014-09-01

373

Antipyrine clearance during experimental and occupational exposure to toluene  

DEFF Research Database (Denmark)

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.

DØssing, M; Bælum, Jesper

1983-01-01

374

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

375

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)

376

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

377

Toluene metabolism during exposure to varying concentrations combined with exercise  

DEFF Research Database (Denmark)

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.

Bælum, Jesper; DØssing, M

1987-01-01

378

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

Science.gov (United States)

The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the differential gene expression between the two treatments. Ribosomal and mRNA sequences attributed to a member of the family Peptococcaceae from the order Clostridiales were essentially only detected in the benzene-amended culture samples, implicating this group in the initial catabolism of benzene. Genes similar to each of two subunits of a proposed benzene-carboxylating enzyme were transcribed when the culture was amended with benzene. Anaerobic benzoate degradation genes from strict anaerobes were transcribed only when the culture was amended with benzene. Genes for other benzoate catabolic enzymes and for nitrate respiration were transcribed in both samples, with those attributed to an Azoarcus species being most abundant. These findings indicate that the mineralization of benzene starts with its activation by a strict anaerobe belonging to the Peptococcaceae, involving a carboxylation step to form benzoate. These data confirm the previously hypothesized syntrophic association between a benzene-degrading Peptococcaceae strain and a benzoate-degrading denitrifying Azoarcus strain for the complete catabolism of benzene with nitrate as the terminal electron acceptor. PMID:24795366

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

2014-01-01

379

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Washer, Cheryl E.; Edwards, Elizabeth A.

2007-01-01

380

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

Science.gov (United States)

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

2010-07-01

 
 
 
 
381

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

Science.gov (United States)

...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...

2010-07-01

382

Nonlinear diffusion in Acetone-Benzene Solution  

CERN Document Server

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

Obukhovsky, Vjacheslav V

2010-01-01

383

Continuous operation of foamed emulsion bioreactors treating toluene vapors.  

Science.gov (United States)

Continuous operation of a new bioreactor for air pollution control called the foamed emulsion bioreactor (FEBR) has been investigated. The effect of several liquid feeding strategies was explored. The FEBR exhibited high and steady toluene removal performance (removal efficiency of 89%-94%, elimination capacity of 214-226 g/m3h at toluene inlet concentration of 1 g/m3) for up to 360 h, when 20% of the culture was replaced every 24 h by a nutrient solution containing 4 g/L of potassium nitrate as a nitrogen source. This feeding mode supported a high cell activity measured as INT reduction potential and active cell growth without being subject to nitrogen limitation. In comparison, operating the FEBR with the liquid in a closed loop (i.e., batch) resulted in a significant decrease of both the removal efficiency of toluene and INT reduction activity. Operation with feeding active cells resulted in stable and effective treatment, but would require a significant effort for mass culture preparation. Therefore, the continuous process with periodically feeding nutrients was found to be the most practical and effective operating mode. It also allows for stable operation, as was shown during removal of low concentration of toluene or after pollutant starvation. Throughout the study, INT reduction measurements provided insight into the process. INT reduction activity data proved that under normal operating conditions, the FEBR performance was limited by both the kinetics and by mass transfer. Overall, the results illustrate that engineered gas-phase bioreactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene. PMID:16041806

Kan, Eunsung; Deshusses, Marc A

2005-11-01

384

Partial hydrogenation of benzene to cyclohexene  

Science.gov (United States)

We (Asahi Chemical Industy Co., Ltd.) have developed a technology for a highly selective partial hydrogenation of benzene to cyclohexene and succeeded in the commercialization of a new production process for producing cyclohexanol from benzene through cyclohexene. The process has been considered to be difficult for a long time in the industry. Several innovative technologies made the partial hydrogenation reaction possible. A catalyst that consists of specific metallic ruthenium particles exhibited excellent high selectivity of cyclohexene. The catalyst was obtained by reducing a ruthenium compound which contains a zinc compound. The use of a zinc of strong acid as a co-catalyst exhibited a remarkable effect to enhance selectivity. Dispersing agents of metal oxides were found to extend the life of the metallic ruthenium catalyst and some dispersing agents had the effect of enhancing the selectivity in the partial hydrogenation reaction. One of the remarkable features of the reaction was the reaction field. This comprises four phases: vapor (hydrogen), oil, aqueous and solid (ruthenium catalyst). The catalyst was used in the aqueous phase, and the reactants (benzene and hydrogen) were dissolved in the aqueous phase where the reaction proceeded. Therefore the products and reactants transfer between four phases through dissolution, diffusion and extraction, rendering quick transfer was a very important factor in enhancing reaction selectivity. The catalyst system and the reaction field described above made the selectivity for cyclohexene very high, and a yield of 60% for cyclohexene was obtained.

Nagahara, H.; Ono, M.; Konishi, M.; Fukuoka, Y.

1997-11-01

385

Ethyl 2-(3,5-dinitrobenzamidobenzoate  

Directory of Open Access Journals (Sweden)

Full Text Available The title molecule, C16H13N3O7, is slightly twisted, with the dihedral angle between the two benzene ring planes being 17.4?(1°. An intramolecular N—H...O hydrogen bond is observed. In the crystal, weak C—H...O hydrogen bonds link the molecules into chains along the b axis.

Sohail Saeed

2012-01-01

386

Ethyl 3-[6-(4-methoxybenzenesulfonamido-2H-indazol-2-yl]propanoate monohydrate  

Directory of Open Access Journals (Sweden)

Full Text Available In the title compound, C19H21N3O5S·H2O, the central indazole system is essentially planar (r.m.s. deviation = 0.012?Å, while both the benzene ring and the mean plane defined by the non-H atoms of the ethyl propionic ester unit (r.m.s. deviation = 0.087?Å are nearly perpendicular to the indazole plane, as indicated by the dihedral angles of 82.45?(8 and 75.62?(8°, respectively. Consequently, the molecule adopts a U-shaped geometry. In the crystal, the water molecule, which is linked to the indazole system by a strong O—H...N hydrogen bond, is also involved in two additional N—H...O and O—H...O interactions, which link the organic molecules into chains along the b-axis direction.

Najat Abbassi

2013-02-01

387

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

388

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

DEFF Research Database (Denmark)

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.

Shunmugavel, Saravanamurugan; Riisager, Anders

2012-01-01

389

A Set of Genes Encoding a Second Toluene Efflux System in Pseudomonas putida DOT-T1E Is Linked to the tod Genes for Toluene Metabolism  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sequence analysis in Pseudomonas putida DOT-T1E revealed a second toluene efflux system for toluene metabolism encoded by the ttgDEF genes, which are adjacent to the tod genes. The ttgDEF genes were expressed in response to the presence of aromatic hydrocarbons such as toluene and styrene in the culture medium. To characterize the contribution of the TtgDEF system to toluene tolerance in P. putida, site-directed mutagenesis was used to knock out the gene in the wild-type DOT-T1E strain and in...

Mosqueda, Gilberto; Ramos, Juan-luis

2000-01-01

390

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

International Nuclear Information System (INIS)

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

391

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-11-15

392

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)

393

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

Directory of Open Access Journals (Sweden)

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.

R.C. Werlang

2002-04-01

394

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

2002-04-01

395

PREFRACTIONATION OF HIGH BENZENE PRECURSORS’ FEED FOR HYBRID REFORMER UNIT  

Directory of Open Access Journals (Sweden)

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.

K. Kirilov

2008-03-01

396

Ethyl 3-(2,4-dichlorobenzylidenecarbazate  

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Full Text Available The title compound, C10H10Cl2N2O2, was prepared by the reaction of ethyl carbazate and 2,4-dichlorobenzaldehyde. In the crystal structure, molecules are linked by intermolecular N—H...O hydrogen bonds, forming extended chains along [001].

Yu-Feng Li

2009-11-01

397

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...

398

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2002-01-01

399

Fatty Acid Ethyl Esters and Ethyl Glucuronide as Markers for Chronic Excessive Alcohol Consumption  

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Alcohol abuse and its consequences such as severe illnesses, accidents or violence are major problems in western societies. Therefore, reliable and accurate biomarkers are required to objectively monitor alcohol consumption. The aim of this research project was to validate analytical methods for the determination of fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG) as long term alcohol abuse markers. Both markers are minor metabolites which are released during non-oxidative alcoh...

Hastedt, Martin

2013-01-01

400

(2-Ethyl-2-oxazoline-?Nbis(N-ethyl-N-phenyldithiocarbamato-?2S,S?cadmium  

Directory of Open Access Journals (Sweden)

Full Text Available In the title compound, [Cd(C9H10NS22(C5H9NO], the CdII atom is five-coordinated in a distorted square-pyramidal geometry by four S atoms from two chelating N-ethyl-N-phenyl dithiocarbamate ligands and one N atom from a 2-ethyl-2-oxazoline ligand. Intermolecular C—H...? interactions are observed in the crystal structure.

Damian C. Onwudiwe

2012-10-01

 
 
 
 
401

Use of modified clay materials in toluene conversion  

International Nuclear Information System (INIS)

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

402

Total oxidation of toluene over calcined trimetallic hydrotalcites type catalysts  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-05-15

403

Total oxidation of toluene over calcined trimetallic hydrotalcites type catalysts.  

Science.gov (United States)

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 degrees C and the resulting catalysts were tested on reaction of total oxidation of toluene. The solids were characterized by X-ray diffraction, thermal analysis, atomic absorption spectroscopy, Fourier transformed infrared spectroscopy, N(2) adsorption and H(2) temperature-programmed reduction. It was found that ZnCuAl materials are composed of copper and zinc oxides supported on alumina; while MnCuAl ones comprise basically spinel phases, which were not completely identified. The catalytic behavior of the calcined samples showed that Mn hydrotalcite calcined at 450 degrees C exhibited the best catalytic performance that corresponds to 100% toluene conversion into CO(2) at about 300 degrees C. PMID:20047794

Palacio, Luz A; Velásquez, Juliana; Echavarría, Adriana; Faro, Arnaldo; Ribeiro, F Ramôa; Ribeiro, M Filipa

2010-05-15

404

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.

405

21 CFR 172.872 - Methyl ethyl cellulose.  

Science.gov (United States)

...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...

2010-04-01

406

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2000-01-01

407

Antibodies to toluene diisocyanate in an environmentally exposed population.  

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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...

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

1998-01-01

408

2-Chloro-N-(4-chlorobenzoyl)benzenesulfonamide toluene hemisolvate  

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The unit cell of the title compound, C13H9Cl2NO3S·0.5C7H8, contains two molecules of 2-chloro-N-(4-chlorobenzoyl)benzenesulfonamide and one toluene molecule, which is disordered about a centre of inversion. The dihedral angle between the two aromatic rings is 85.7?(1)°. In the crystal, molecules are linked by pairs of N—H...O(S) hydrogen bonds, forming centrosymmetric dimers.

Thimme Gowda, B.; Sabine Foro; Suchetan, P. A.

2011-01-01

409

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

410

Experimental Emulsified Diesel and Benzen Investigation  

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

Suleiman Abu-Ein

2010-05-01

411

Hematotoxicity and carcinogenicity of inhaled benzene.  

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CBA/Ca male mice have been exposed to benzene in air at 10, 25, 100, 300, 400, and 3000 ppm for variable intervals 6 hr/day, 5 days/week for up to 16 weeks. Two weeks of inhaling 10 ppm produced no hematologic effects; 25 ppm induced a significant lymphopenia. Inhalation of 100, 300, and 400 ppm produced dose-dependent decreases in blood lymphocytes, bone marrow cellularity, marrow content of spleen colony-forming units (CFU-S) and an increased fraction of CFU-S in DNA synthesis. Exposure of ...

Cronkite, E. P.; Drew, R. T.; Inoue, T.; Hirabayashi, Y.; Bullis, J. E.

1989-01-01

412

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.

413

Ethyl 8,13-dioxa-21-aza­penta­cyclo­[18.5.1.02,7.014,19.021,25]hexa­cosa-2(7),3,5,14,16,18-hexa­ene-26-carboxyl­ate  

Science.gov (United States)

In the title compound, C26H31NO4, the five-membered rings of the central pyrrolizine system adopt N-envelope conformations. The ethyl acetate group adopts an extended conformation. The dihedral angle between the benzene rings is 36.6?(1)°. In the crystal, C—H?O hydrogen bonds form a zigzag chain running along the b-axis directions. The crystal structure is futher consolidated by C—H?? inter­actions. PMID:23476412

Narayanan, Sibi; Srinivasan, Thothadri; Purushothaman, Santhanagopalan; Raghunathan, Raghavachary; Velmurugan, Devadasan

2013-01-01

414

Ethyl 8,13-dioxa-21-azapentacyclo[18.5.1.02,7.014,19.021,25]hexacosa-2(7,3,5,14,16,18-hexaene-26-carboxylate  

Directory of Open Access Journals (Sweden)

Full Text Available In the title compound, C26H31NO4, the five-membered rings of the central pyrrolizine system adopt N-envelope conformations. The ethyl acetate group adopts an extended conformation. The dihedral angle between the benzene rings is 36.6?(1°. In the crystal, C—H...O hydrogen bonds form a zigzag chain running along the b-axis directions. The crystal structure is futher consolidated by C—H...? interactions.

Devadasan Velmurugan

2013-01-01

415

Ethyl 8,13-dioxa-21-aza­penta­cyclo­[18.5.1.02,7.014,19.021,25]hexa­cosa-2(7),3,5,14,16,18-hexa­ene-26-carboxyl­ate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the title compound, C26H31NO4, the five-membered rings of the central pyrrolizine system adopt N-envelope conformations. The ethyl acetate group adopts an extended conformation. The dihedral angle between the benzene rings is 36.6?(1)°. In the crystal, C—H...O hydrogen bonds form a zigzag chain running along the b-axis directions. The crystal structure is futher consolidated by C—H...? interactions.

Devadasan Velmurugan; Raghavachary Raghunathan; Santhanagopalan Purushothaman; Thothadri Srinivasan; Sibi Narayanan

2012-01-01

416

3-Benzyl-4-ethyl-1H-1,2,4-triazole-5(4H-thione  

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Full Text Available The title compound, C11H13N3S, exists in the 5-thioxo tautomeric form. The benzene ring exhibits disorder with a refined ratio of 0.77?(2:0.23?(2 for components A and B with a common bridgehead C atom. The 1,2,4-triazole ring is essentially planar, with a maximum deviation of 0.002?(3?Å for the benzyl-substituted C atom, and forms dihedral angles of 88.94?(18 and 86.56?(49° with the benzene rings of components A and B, respectively. The angle between the plane of the ethyl chain and the mean plane of 1,2,4-triazole ring is 88.55?(15° and this conformation is stabilized by an intramolecular C—H...S contact. In the crystal, pairs of N—H...S hydrogen bonds link molecules into inversion dimers. ?–? interactions are observed between the triazole and benzene rings, with centroid–centroid separations of 3.547?(4 and 3.544?(12?Å for components A and B, and slippages of 0.49?(6 and 0.58?(15?Å, respectively.

Zbigniew Karczmarzyk

2013-02-01

417

3-Benzyl-4-ethyl-1H-1,2,4-triazole-5(4H)-thione.  

Science.gov (United States)

The title compound, C(11)H(13)N(3)S, exists in the 5-thioxo tautomeric form. The benzene ring exhibits disorder with a refined ratio of 0.77?(2):0.23?(2) for components A and B with a common bridgehead C atom. The 1,2,4-triazole ring is essentially planar, with a maximum deviation of 0.002?(3)?Å for the benzyl-substituted C atom, and forms dihedral angles of 88.94?(18) and 86.56?(49)° with the benzene rings of components A and B, respectively. The angle between the plane of the ethyl chain and the mean plane of 1,2,4-triazole ring is 88.55?(15)° and this conformation is stabilized by an intra-molecular C-H?S contact. In the crystal, pairs of N-H?S hydrogen bonds link mol-ecules into inversion dimers. ?-? inter-actions are observed between the triazole and benzene rings, with centroid-centroid separations of 3.547?(4) and 3.544?(12)?Å for components A and B, and slippages of 0.49?(6) and 0.58?(15)?Å, respectively. PMID:23424446

Karczmarzyk, Zbigniew; Pitucha, Monika; Wysocki, Waldemar; Pachuta-Stec, Anna; Sta?czuk, Andrzej

2013-02-01

418

N-[(2,6-Di-ethyl-phen-yl)carbamo-thio-yl]-2,2-di-phenyl-acetamide.  

Science.gov (United States)

In the title compound, C25H26N2OS, the diethyl-substituted benzene ring forms dihedral angles of 67.38?(9) and 55.32?(9)° with the terminal benzene rings. The mol-ecule adopts a trans-cis conformation with respect to the orientations of the di-phenyl-methane and 1,3-di-ethyl-benzene groups with respect to the S atom across the C-N bonds. This conformation is stabilized by an intra-molecular N-H?O hydrogen bond, which generates an S(6) ring. In the crystal, pairs of N-H?S hydrogen bonds link the mol-ecules into inversion dimers, forming R 2 (2)(6) loops. The dimer linkage is reinforced by a pair of C-H?S hydrogen bonds, which generate R 2 (2)(8) loops. Weak C-H?? and ?-? [centroid-centroid seperation = 3.8821?(10)?Å] inter-actions also occur in the crystal structure. PMID:23795124

Yusof, Mohd Sukeri Mohd; Razali, Nur Rafikah; Arshad, Suhana; Rahman, Azhar Abdul; Razak, Ibrahim Abdul

2013-06-01

419

N-[(2,6-Di­ethyl­phen­yl)carbamo­thio­yl]-2,2-di­phenyl­acetamide  

Science.gov (United States)

In the title compound, C25H26N2OS, the diethyl-substituted benzene ring forms dihedral angles of 67.38?(9) and 55.32?(9)° with the terminal benzene rings. The mol­ecule adopts a trans–cis conformation with respect to the orientations of the di­phenyl­methane and 1,3-di­ethyl­benzene groups with respect to the S atom across the C—N bonds. This conformation is stabilized by an intra­molecular N—H?O hydrogen bond, which generates an S(6) ring. In the crystal, pairs of N—H?S hydrogen bonds link the mol­ecules into inversion dimers, forming R 2 2(6) loops. The dimer linkage is reinforced by a pair of C—H?S hydrogen bonds, which generate R 2 2(8) loops. Weak C—H?? and ?–? [centroid–centroid seperation = 3.8821?(10)?Å] inter­actions also occur in the crystal structure. PMID:23795124

Yusof, Mohd Sukeri Mohd; Razali, Nur Rafikah; Arshad, Suhana; Rahman, Azhar Abdul; Razak, Ibrahim Abdul

2013-01-01

420

(E-Ethyl N?-(4-bromobenzylidenehydrazinecarboxylate  

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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.

Bo Gao

2008-08-01

 
 
 
 
421

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

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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,