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Toluol Recovery

Description: Technical paper issued by the Bureau of Standards over toluol-recovery, known as light oil. The methods used in the toluol-recovery are presented and discussed. This paper includes tables, and illustrations.
Date: December 19, 1918
Creator: McBride, R. S.; Reinicker, C. E. & Dunkley, W. A.
Partner: UNT Libraries Government Documents Department

Effect of Key Parameters on the Photocatalytic Oxidation of Toluene at Low Concentrations in Air under 254 + 185 nm UV Irradiation

Description: The effect of key experimental parameters on the removal of toluene under 254 + 185 nm irradiation was investigated using a benchtop photocatalytic flow reactor. Toluenewas introduced at low concentrations between 10 and 500 ppbv, typical of indoorenvironments, and reacted on TiO2-coated Raschig rings. Two different TiO2-coated rings were prepared: in one case, by dip-coating using a P25 aqueous suspension and, on the other, using an organic/inorganic sol-gel method that produced thin films of mesoporous anatase. Flow rates in the photoreactor varied between 4 L min-1 and 125 mL min-1, leading to residence times in the range 100 ms< tau< 2 s. For these conditions, toluene removal efficiencies were between 30 and 90percent, indicating that the system did not achieve total conversion in any case. For each air flow rate, the conversion oftoluene was significantly higher when the reactor length was 10 cm, as compared with 5 cm; however, only marginal increases in conversions were achieved in the two reactor lengths at equal residence time and different concentration of toluene, suggesting that that the reactor is effectively behaving as an ideal reactor and that the reaction is first-order in the concentration of toluene. Experiments were carried out between 0 and 66percent relative humidity (RH), the fastest reaction rate being observed at moderately low humidity conditions (10percent RH), with respect to both dry air and higher humidity levels. Formaldehyde was formed as a partial oxidation byproduct at low and at high residence times (240 and 960 ms), although higher formaldehyde molar yields (up to 20percent) were observed at low tau (240 ms) and moderate humidity conditions (10 and 33percent), suggesting that both tau and RH can be optimized toreduce the formation of harmful intermediates. Toluene removal efficiency increased with the TiO2 thickness (i.e., mass) until a maximum value of 500 nm, ...
Date: July 1, 2009
Creator: Quici, Natalia; Vera, Maria L.; Choi, Hyeok; Puma, Gianluca Li; Dionysiou, Dionysios D.; Litter, Marta I. et al.
Partner: UNT Libraries Government Documents Department

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

Description: 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).
Date: December 23, 2009
Creator: Trevitt, Adam J.; Goulay, Fabien; Taatjes, Craig A.; Osborn, David L. & Leone, Stephen R.
Partner: UNT Libraries Government Documents Department

Electric Field Assisted Assembly of Perpendicular Oriented NanorodSuperlattices

Description: We observe the assembly of CdS nanorod superlattices by thecombination of a DC electric field and solvent evaporation. In eachelectric field (1 V/um) assisted assembly, CdS nanorods (5 x 30 nm)suspended initially in toluene were observed to align perpendicularly tothe substrate. Azimuthal alignment along the nanorod crystal faces andthe presence of stacking faults indicate that both 2D and 3D assemblieswere formed by a process of controlled super crystal growth.
Date: April 10, 2006
Creator: Ryan, Kevin M.; Mastroianni, Alex; Stancil, Kimani A.; Liu,Haitao & Alivisatos, Paul A.
Partner: UNT Libraries Government Documents Department

Method to prepare Semtex

Description: This procedure requires the binder and uncoated RDX be prepared in separate steps, see Figure 1: (1) The binder and dye are mixed by agitation with a water-insoluble organic solvent (e.g., toluene), I; (2) The RDX/PETN is agitated thoroughly with water, II; (3) The binder solution I is added to the RDX/water mixture at II with thorough mixing to form a slurry III; (4) In the next step the solvent is distilled off at IV leaving resulting granules; (5) The next step is followed by filtration at V, which may be done by vacuum; (6) The composition is then dried at VI to a dough-like consistency.
Date: November 26, 2006
Creator: Alcaraz, A & Dougan, A
Partner: UNT Libraries Government Documents Department

Heavy Oil Process Monitor: Automated On-Column Asphaltene Precipitation and Re-Dissolution

Description: An automated separation technique was developed that provides a new approach to measuring the distribution profiles of the most polar, or asphaltenic components of an oil, using a continuous flow system to precipitate and re-dissolve asphaltenes from the oil. Methods of analysis based on this new technique were explored. One method based on the new technique involves precipitation of a portion of residua sample in heptane on a polytetrafluoroethylene-packed (PTFE) column. The precipitated material is re-dissolved in three steps using solvents of increasing polarity: cyclohexane, toluene, and methylene chloride. The amount of asphaltenes that dissolve in cyclohexane is a useful diagnostic of the thermal history of oil, and its proximity to coke formation. For example, about 40 % (w/w) of the heptane asphaltenes from unpyrolyzed residua dissolves in cyclohexane. As pyrolysis progresses, this number decrease to below 15% as coke and toluene insoluble pre-coke materials appear. Currently, the procedure for the isolation of heptane asphaltenes and the determination of the amount of asphaltenes soluble in cyclohexane spans three days. The automated procedure takes one hour. Another method uses a single solvent, methylene chloride, to re-dissolve the material that precipitates on heptane on the PTFE-packed column. The area of this second peak can be used to calculate a value which correlates with gravimetric asphaltene content. Currently the gravimetric procedure to determine asphaltenes takes about 24 hours. The automated procedure takes 30 minutes. Results for four series of original and pyrolyzed residua were compared with data from the gravimetric methods. Methods based on the new on-column precipitation and re-dissolution technique provide significantly more detail about the polar constituent's oils than the gravimetric determination of asphaltenes.
Date: March 31, 2007
Creator: Schabron, John F.; Rovani, Joseph F. & Sanderson, Mark
Partner: UNT Libraries Government Documents Department

Electrospun a-Si using Liquid Silane/Polymer Inks

Description: Amorphous silicon nanowires (a-SiNWs) were prepared by electrospinning cyclohexasilane (Si{sub 6}H{sub 12}) admixed with polymethylmethacrylate (PMMA) in toluene. Raman spectroscopy characterization of these wires (d {approx} 50-2000 nm) shows 350 C treatment yields a-SiNWs. Porous a-SiNWs are obtained using a volatile polymer.
Date: December 9, 2010
Creator: Schulz, Doug
Partner: UNT Libraries Government Documents Department

Electrospun a-Si using Liquid Silane/Polymer Inks

Description: Amorphous silicon nanowires (a-SiNWs) were prepared by electrospinning cyclohexasilane (Si{sub 6}H{sub 12}) admixed with polymethylmethacrylate (PMMA) in toluene. Raman spectroscopy characterization of these wires (d {approx} 50-2000 nm) shows 350 C treatment yields a-SiNWs. Porous a-SiNWs are obtained using a volatile polymer.
Date: December 1, 2010
Creator: Schulz, D.L.; Hoey, J.M.; Smith, J.; Lovaasen, J.; Braun, C.; Dai, X. et al.
Partner: UNT Libraries Government Documents Department

Cometabolic bioremediation

Description: Cometabolic bioremediation is probably the most under appreciated bioremediation strategy currently available. Cometabolism strategies stimulate only indigenous microbes with the ability to degrade the contaminant and cosubstrate e.g. methane, propane, toluene and others. This highly targeted stimulation insures that only those microbes that can degrade the contaminant are targeted, thus reducing amendment costs, well and formation plugging, etc. Cometabolic bioremediation has been used on some of the most recalcitrant contaminants, e.g. PCE, TCE, MTBE, TNT, dioxane, atrazine, etc. Methanotrophs have been demonstrated to produce methane monooxygense, an oxidase that can degrade over 300 compounds. Cometabolic bioremediation also has the advantage of being able to degrade contaminants to trace concentrations, since the biodegrader is not dependent on the contaminant for carbon or energy. Increasingly we are finding that in order to protect human health and the environment that we must remediate to lower and lower concentrations, especially for compounds like endocrine disrupters, thus cometabolism may be the best and maybe the only possibility that we have to bioremediate some contaminants.
Date: February 15, 2009
Creator: Hazen, Terry C.
Partner: UNT Libraries Government Documents Department

HINDERED DIFFUSION OF ASPHALTENES AT ELEVATED TEMPERATURE AND PRESSURE

Description: During this time period work proceeded in two main areas, the performance and analysis of petroleum asphaltene diffusional uptake experiments at 325 C and the preparation and testing of some new carbon based catalysts. In the first area, we performed studies of the diffusion controlled uptake of petroleum asphaltenes into a porous carbon catalyst at 325 C. The experiments were performed under an inert He atmosphere using 1-methylnaphthalene as a solvent. These purpose of these experiments was to extend our previous data which was taken and reported in the prior semi-annual report. These previous experiments were performed only up to a temperature of 250 C. A comparison between the experimental data and model simulated data showed that the mathematical model satisfactorily fitted the adsorptive diffusion of the petroleum asphaltenes onto the porous carbon at 325 C. Comparing with previous results, the adsorption constant continued to decrease with an increase in temperature for the petroleum asphaltene/1-methylnaphthalene system. Also during this time period, some carbon catalyst supports were prepared in our laboratory and several sets of data were obtained in adsorption-diffusion uptake experiments using a petroleum asphaltene with toluene as solvent. These data are presented in this report, although, complete fitting of the data with the mathematical model has not yet been performed. These calculations will be performed during the next time period.
Date: September 29, 2000
Creator: Guin, James A.; Ramakrishnan, Ganesh; Asada, Keiji & Mosley, Brian
Partner: UNT Libraries Government Documents Department

HINDERED DIFFUSION OF ASPHALTENES AT ELEVATED TEMPERATURE AND PRESSURE

Description: The mathematical model which we have developed previously for diffusion controlled adsorption was extended to allow for the inclusion of the effects of extraparticle film mass transfer resistance as embodied in a finite Sherwood number. A Mathcad based program was used to simulate the experimental data using summation of a large number of terms in the infinite series solution. Parametric studies and accompanying plots revealed that the effects of film resistance on the uptake process were found to increase in significance as the adsorption capacity parameter in the model decreased. In addition, the two carbon catalyst supports prepared in our own laboratory were tested for their diffusional characteristics in uptake experiments using petroleum asphaltenes dissolved in toluene at three temperatures. The resulting experimental data were simulated with the mathematical model developed in the report.
Date: April 1, 2001
Creator: Guin, James A.; Ramakrishnan, Ganesh; Asada, Keiji & Mosley, Brian
Partner: UNT Libraries Government Documents Department

Evaluating open-path FTIR spectrometer data using different quantification methods, libraries, and background spectra obtained under varying environmental conditions

Description: Studies were performed to evaluate the accuracy of open-path Fourier Transform Infrared (OP-FTIR) spectrometers using a 35 foot outdoor exposure chamber in Pittsboro, North Carolina. Results obtained with the OP-FTIR spectrometer were compared to results obtained with a reference method (a gas chromatograph equipped with a flame ionization detector, GC-FID). Concentration results were evaluated in terms of the mathematical methods and spectral libraries used for quantification. In addition, the research investigated the effect on quantification of using different backgrounds obtained at various times during the day. The chemicals used in this study were toluene, cyclohexane, and methanol; and these were evaluated over the concentration range of 5-30 ppm.
Date: December 31, 1995
Creator: Tomasko, M.S.
Partner: UNT Libraries Government Documents Department

Orthogonal spectra and cross sections: Application to optimization of multi-spectral absorption and fluorescence lidar

Description: This report addresses the problem of selection of lidar parameters, namely wavelengths for absorption lidar and excitation fluorescence pairs for fluorescence lidar, for optimal detection of species. Orthogonal spectra and cross sections are used as mathematical representations which provide a quantitative measure of species distinguishability in mixtures. Using these quantities, a simple expression for the absolute error in calculated species concentration is derived and optimization is accomplished by variation of lidar parameters to minimize this error. It is shown that the optimum number of wavelengths for detection of a species using absorption lidar (excitation fluorescence pairs for fluorescence lidar) is the same as the number of species in the mixture. Each species present in the mixture has its own set of optimum wavelengths. There is usually some overlap in these sets. The optimization method is applied to two examples, one using absorption and the other using fluorescence lidar, for analyzing mixtures of four organic compounds. The effect of atmospheric attenuation is included in the optimization process. Although the number of optimum wavelengths might be small, it is essential to do large numbers of measurements at these wavelengths in order to maximize canceling of statistical errors.
Date: September 1, 1997
Creator: Shokair, I.R.
Partner: UNT Libraries Government Documents Department

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

Description: 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 {micro}m; a search with EPMA for vesicles in the range of 1-20 {micro}m 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 {sup 29}Si MAS NMR spectroscopy, which shows a reduction in chain silicates with added toluene. Also, {sup 2}H NMR of d{sub 8}-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).
Date: July 22, 1999
Creator: BUTLER,L.G.
Partner: UNT Libraries Government Documents Department

The intermolecular vibrational dynamics of substituted benzene and cyclohexane liquids, studied by femtosecond OHD-RIKES

Description: By using the femtosecond optical-heterodyne detected, Raman-induced Kerr effect spectroscopy (OHD-RIKES), we have studied the intermolecular dynamics of toluene, benzyl alcohol, benzonitrile, cyclohexane, and methylcyclohexane in both the time and frequency domains.
Date: June 1, 1995
Creator: Castner, E.W. Jr. & Chang, Yong Joon
Partner: UNT Libraries Government Documents Department

Mass Spectrometric Fingerprinting of Tank Waste Using Tunable, Ultrafast Infrared Lasers

Description: During the past year, we have initiated systematic studies of mass spectrometry of model tank-waste materials using both conventional nanosecond, single-frequency and tunable, subpicosecond mid-infrared lasers. In addition to making initial measurements, we have also constructed several new items of equipment for the experiment and begun to develop a model of the processes which lead to efficient desorption and ionization of organic molecules (e.g., toluene, benzene, crown ethers) from sodium nitrate. Comparisons of nanosecond and picosecond lasers, and of infrared and ultraviolet lasers, have been especially instructive. These accomplishments are detailed in the following paragraphs.
Date: June 1, 1999
Creator: Haglund, Richard F., Jr. & Hess, Wayne P.
Partner: UNT Libraries Government Documents Department

The Chelate Process I

Description: The chelate process for the extraction and decontamination of plutonium has been investigated. The process is designed as an alternate process for ihe Hanford type operation. The basic chemical factors have been studied and two flowsheeis have been developed and tested for recovery of plutonium. An over-all yield of plutonium in excess of 99% is reported for one flowsheet using benzene as the organic solvent and 98.5% when toluene was substituted for benzene. The general factors involved in establishing all details of the flowsheets are thoroughly discussed and decontamination studies are indicated to complete the study in the present equipment. (auth)
Date: December 12, 1946
Creator: Thomas, J. R. & Crandall, H. W.
Partner: UNT Libraries Government Documents Department

Complete genome sequence of Tolumonas auensis type strain (TA 4T)

Description: Tolumonas auensis (Fischer-Romero et al. 1996) is currently the only validly named species of the genus Tolumonas in the family Aeromonadaceae. The strain is of interest because of its ability to produce toluene from phenylalanine and other phenyl precursors, as well as phenol from tyrosine. This is of interest because toluene is normally considered to be a tracer of anthropogenic pollution in lakes, but T. auensis represents a biogenic source of toluene. Other than Aeromonas hydrophila subsp. hydrophila, T. auensis strain TA 4T is the only other member in the family Aeromonadaceae with a completely sequenced type-strain genome. The 3,471,292-bp chromosome with a total of 3,288 protein-coding and 116 RNA genes was sequenced as part of the DOE Joint Genome Institute Program JBEI 2008.
Date: October 4, 2011
Creator: Chertkov, Olga; Copeland, Alex; Lucas1, Susa; Lapidus, Alla; Berry, KerrieW.; Detter, JohnC. et al.
Partner: UNT Libraries Government Documents Department

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

Description: The overall objectives of the project were to: (a) develop an economically competitive processing technology for styrene monomer (SM) that would reduce process energy requirements by a minimum 25% relative to those of conventional technology while achieving a minimum 10% ROI; and (b) advance the technology towards commercial readiness. This technology is referred to as OMT (Oxymethylation of Toluene). The unique energy savings feature of the OMT technology would be replacement of the conventional benzene and ethylene feedstocks with toluene, methane in natural gas and air or oxygen, the latter of which have much lower specific energy of production values. As an oxidative technology, OMT is a net energy exporter rather than a net energy consumer like the conventional ethylbenzene/styrene (EB/SM) process. OMT plants would ultimately reduce the cost of styrene monomer which in turn will decrease the costs of polystyrene making it perhaps more cost competitive with competing polymers such as polypropylene.
Date: November 29, 2011
Creator: Trubac, Robert , E.; Lin, Feng & Ghosh, Ruma: Greene, Marvin
Partner: UNT Libraries Government Documents Department