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Bioprocessing of crude oils and desulfurization using electro-spray reactors

Description: Biological removal of organic sulfur from petroleum feedstocks offers an attractive alternative to conventional thermochemical treatment due to the mild operating conditions afforded by the biocatalyst. Electro-spray bioreactors were investigated for use in desulfurization due to their reported operational cost savings relative to mechanically agitated reactors and their capability of forming emulsions < 5 {micro}m. Here, the rates dibenzothiophene (DBT) oxidation to 2-hydroxybiphenyl (2-HBP) in hexadecane, by Rhodococcus sp. IGTS8 are compared in the two reactor systems. Desulfurization rates ranged from 1.0 and 5.0 mg 2-HBP/(dry g cells-h), independent of the reactor employed. The batch stirred reactor was capable of forming a very fine emulsion in the presence of the biocatalyst IGTS8, similar to that formed in the electro-spray reactors, presumably due to the fact that the biocatalyst produces its own surfactant. While electro-spray reactors did not prove to be advantageous for the IGTS8 desulfurization system, it may prove advantageous for systems which do not produce surface-active bioagents in addition to being mass transport limited.
Date: July 1, 1998
Creator: Kaufman, E. N. & Borole, A. P.
Partner: UNT Libraries Government Documents Department

Single- and multi-photon ionization studies of organosulfur species

Description: Accurate ionization energies (IE`s) for molecular species are used for prediction of chemical reactivity and are of fundamental importance to chemists. The IE of a gaseous molecule can be determined routinely in a photoionization or a photoelectron experiment. IE determinations made in conventional photoionization and photoelectron studies have uncertainties in the range of 3--100 meV (25--250 cm{sup {minus}1}). In the past decade, the most exciting development in the field of photoionization and photoelectron spectroscopy has been the availability of high resolution, tunable ultraviolet (UV) and vacuum ultraviolet (VUV) laser sources. The laser pulsed field ionization photoelectron (PFI-PE) scheme is currently the state-of-the-art photoelectron spectroscopic technique and is capable of providing photoelectron energy resolution close to the optical resolution. The author has focused attention on the photoionization processes of some sulfur-containing species. The studies of the photoionization and photodissociation on sulfur-containing compounds [such as CS{sub 2}, CH{sub 3}SH, CH{sub 3}SSCH{sub 3}, CH{sub 3}CH{sub 2}SCH{sub 2}CH{sub 3}, HSCH{sub 2}CH{sub 2}SH and C{sub 4}H{sub 4}S (thiophene) and sulfur-containing radicals, such as HS, CS, CH{sub 3}S, CH{sub 3}CH{sub 2}S and CH{sub 3}SS], have been the major subjects in the group because sulfur is an important species contributing to air pollution in the atmosphere. The modeling of the combustion and oxidation of sulfur compounds represents important steps for the control of both the production and the elimination of sulfur-containing pollutants. Chapter 1 is a general introduction of the thesis. Chapters 2 and 6 contain five papers published in, or accepted for publication in, academic periodicals. In Chapter 7, the progress of the construction in the laboratory of a new vacuum ultraviolet laser system equipped with a reflectron mass spectrometer is presented. Chapters 2 through 7 have been removed for separate processing. A general conclusion of these studies are given in Chapter 8 followed by an ...
Date: February 12, 1999
Creator: Cheung, Y.S.
Partner: UNT Libraries Government Documents Department

Development and application of thin-layer spectroelectrochemical techniques for the study of organosulfur monolayers adsorbed at gold

Description: A main research interest is the characterization of monolayers formed by the spontaneous adsorption of organosulfur compounds at gold. This dissertation describes the development and application of long optical pathlength thin-layer spectroelectrochemistry in an attempt to address key issues regarding the reactivity of surface-immobilized molecules. The first section of this introductory chapter briefly describes the general approach to the preparation and characterization of these films. The last section provides an overview of the main principles and advantages of thin-layer spectroelectrochemistry for studying surface-adsorbed species. The body of this dissertation is divided into four chapters. Chapter 2 consists of a paper describing the design, construction, and characterization of a cuvette-based LOPTLC. Chapter 3 is a paper which examines the reductive desorption process using thin-layer spectroelectrochemistry to monitor and identify the desorption product. Chapter 4 is a paper describing the characterization of monolayers functionalized with a catechol terminal group which serves as a redox transformable coordination site for metal ion binding. Chapter 5 discusses the application of thin-layer spectroelectrochemistry to acid-base reactivity studies of surface-immobilized molecules. The final section provides some general conclusions and a prospectus for future studies. These chapters have been processed separately for inclusion on the data base. This report contains the introduction, references, and general conclusions. 78 refs.
Date: October 8, 1997
Creator: Simmons, N.
Partner: UNT Libraries Government Documents Department

SULFUR REDUCTION IN GASOLINE AND DIESEL FUELS BY EXTRACTION/ADSORPTION OF REFRACTORY DIBENZOTHIOPHENES

Description: Using the classical coordination compound, Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+}, they have prepared a metal complex with a 4,6-dimenthyldibenzothiophene ligand. The compound Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} also reacts with thiophene, benzothiophene and dibenzothiophene (DBT) at room temperature. They have found that Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} removes over 50% of the DBT in simulated petroleum feedstocks by a biphasic extraction process. The extraction phase is readily generated by air-oxidation thereby completing a cyclic process that removes DBT from petroleum feedstocks.
Date: October 1, 2001
Creator: Angelici, Robert J.; McKinley, Scott G. & Alvarez, Celedonio
Partner: UNT Libraries Government Documents Department

Near-field single molecule spectroscopy

Description: The high spatial resolution and sensitivity of near-field fluorescence microscopy allows one to study spectroscopic and dynamical properties of individual molecules at room temperature. Time-resolved experiments which probe the dynamical behavior of single molecules are discussed. Ground rules for applying near-field spectroscopy and the effect of the aluminum coated near-field probe on spectroscopic measurements are presented.
Date: February 1, 1995
Creator: Xie, X.S. & Dunn, R.C.
Partner: UNT Libraries Government Documents Department

SCAVENGING OF RUTHENIUM FROM PUREX URANYL NITRATE SOLUTION

Description: Ruthenium in uranyl nitrate solutions from the Purex Process was adsorbed by the solid residue that remains when the solutions are concentrated by evaporation after treatment with thiocarbanilide and thioacetarnide. Other chemicals were tested and the results are summarized. (auth)
Date: June 1, 1958
Creator: Prohaska, C.A.
Partner: UNT Libraries Government Documents Department

Organusulfur Catalysis With Reduced Molybdenum Sulfides Containing the Mo6S8 Cluster

Description: Industrial synthesis of sulfur-containing organic chemicals basically focuses on the broad categories of mercaptans (thiols), alkylsulfides (thioethers), polysulfides, and thiophenes. Of the organo-sulfur compounds produced, by far the most important in terms of quantities produced is methyl mercaptan (methanethiol or MeSH), which is produced mainly for the downstream production of methionine and methanesulfonyl chloride. Higher thiols are also used in the manufacture of rubber and plastics as polymerization regulators, chain transfer agents, or initiators. Other important organosulfur chemicals are dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), both of which are used extensively for presulfiding of industrial hydroprocessing catalysts, and substituted thiophenes which are used as intermediates for production of agrochemicals, dyes, and pharmaceuticals. Thiols are produced commercially at the rate of about 10{sup 4} ton/yr from hydrogen sulfide (H{sub 2}S) and alcohols or olefins, using homogeneous free-radical synthesis, or heterogeneous catalysts based on solid acids or supported metal oxides and/or sulfides. Despite this large production rate, and the industrial importance of the organosulfur compounds, only limited research has been devoted to the development of new catalytic materials for their synthesis. Additionally, for most organosulfur catalytic reactions, only limited information exists about reaction mechanisms, active sites, adsorbed surface species, and especially the nature of the catalysts under reaction conditions.
Date: August 27, 2002
Creator: Paskach, Thomas Jay
Partner: UNT Libraries Government Documents Department

Desulfurization of coal with hydroperoxides of vegetable oils. Technical progress report, March 1--May 31, 1995

Description: This project proposes a new method for removing organic sulfur from Illinois coals using readily available farm products. It proposes to use air and vegetable oils to disrupt the coal matrix, oxidize sulfur forms, increase volatiles, and desulfurize coal. This will be accomplished by impregnating coals with polyunsaturated oils, converting the oils to their hydroperoxides, and heating. Since these oils are relatively inexpensive and easily applied, this project could lead to a cost effective method for removing organic sulfur from coals. Moreover, the oils are environmentally safe; they will produce no noxious products and will improve burning qualities of solid products. Preliminary experiments showed that IBC 104 coal catalyzes the formation of hydroperoxides in safflower oil and that more sulfur is extracted from the treated than untreated coal. During the first quarter the requirement of an added photosensitizer was eliminated, the catalytic effect of coal was confirmed, and the existence of a complex set of reactions was revealed. During the second quarter, working with IBC-108 coal (2.3% organic S, 0.4% pyrite S), the effects of different extraction solvents were examined. A new pretreatment which combines alkali with linseed oil was discovered. Best organic sulfur removal is approximately 26% using alkali pretreatment combined with linseed oil at 100[degrees]C. BTU loses can be kept to a minimum of 3% with proper use of solvents. During this third quarter the effects of different ratios of oil:coal, different temperatures, and different reaction times were completely examined. The effects of alkali on sulfur removal were further investigated. Best organic sulfur removal reaches 34% using ammonia pretreatment, then oil and finally aqNA2CO3 extraction.
Date: December 31, 1995
Creator: Smith, G.V.; Gaston, R.D.; Song, R.; Cheng, J.; Shi, Feng & Gholson, K.L.
Partner: UNT Libraries Government Documents Department

Environmental significance of biocatalytic conversion of low grade oils

Description: Studies dealing with the interactions between extremophilic microorganisms and crude oils have led to the identification of biocatalysts which through multiple biochemical reactions catalyze desulfurization, denitrogenation, and demetalation reactions in oils. Concurrently, the oils are also converted to lighter oils. These complex biochemical reactions have served as models in the development of the crude oil bioconversion technology to be applied prior to the treatment of oils by conventional chemical processes. In practical terms, this means that the efficiency of the existing technology is being enhanced. For example, the recently introduced additional regulation for the emission of nitrogen oxides in some states restricts further the kinds of oils that may be used in burners. The biocatalysts being developed in this laboratory selectively interact with nitrogen compounds, i.e. basic and neutral types present in the oil and, hence, affect the fuel NOx production. This, in turn, has a cost-efficient influence on the processed oils and their consumption. In this paper, these cost-efficient and beneficial effects will be discussed in terms of produced oils, the lowering of sulfur and nitrogen contents, and the effect on products, as well as the longevity of catalysts due to the removal of heteroatoms and metal containing compounds found in crudes.
Date: September 1, 1996
Creator: Lin, M.S.; Premuzic, E.T.; Lian, H.; Zhou, W.M. & Yablon, J.
Partner: UNT Libraries Government Documents Department

Tribology studies of organic thin films by scanning force microscopy

Description: The use of organic thin films as lubricants on solid surfaces is important in many modern technologies including magnetic storage and micromachines. Langmuir-Blodgett (LB) films and self-assembled monolayers (SAMs) are attractive candidates for lubricant layers and for model studies of lubrication because of their strong adsorption to the surface. The recent interest on the properties of LB films and SAMs has been also motivated by their potential applications in sensors, non-linear optical devices, lithography and microelectronics. Using the micro-contact printing method the authors prepared patterned SAMs consisting of methyl-terminated alkanethiols of different chain lengths. The samples were characterized using lateral force microscopy (LFM) and the force modulation technique (FMT). In general, higher friction is observed over the short chain regions than over the long chain regions when a low or moderate load is applied to the SFM tip. For such cases the high friction (short chain) regions are also ``softer`` as measured by FMT. A high loads, a reversal of the image contrast is observed and the short chain regions show a lower friction than the long chain regions. This image contrast is reversible upon reduction of the applied load.
Date: June 1, 1996
Creator: Bar, G.; Rubin, S.; Parikh, A.N.; Swanson, B.I. & Zawodzinski, T.A.
Partner: UNT Libraries Government Documents Department

The organic chemistry of conducting polymers. Annual technical report, June 1, 1994--September 30, 1995

Description: Earlier research was on finite confinement for the soliton, proton- transfer doping of polyacetylene, electron hopping, Peierls distortion in discrete polyenes (cyanines), conductive heteropolymers, and synthesis and covalent attachment of polymerizable trimers to insulating, conductive, and semiconductive surfaces. The past year`s research was on synthesis of binuclear complexes with soliton-like communication between the two metal centers, and soluble polyheterocycles with remarkable conjugation lengths. These materials show electroluminescence as well.
Date: December 22, 1995
Creator: Tolbert, L.M.
Partner: UNT Libraries Government Documents Department

Fouling formation of an olefin in the presence of oxygen and thiophenol

Description: A kinetic model was developed to predict the fouling rate for autoxidation of indene in the presence of thiophenol. The kinetic constants were determined by analyzing the fouling data obtained with and without thiophenol. An initial rapid formation of hydroperoxide was observed in the presence of thiophenol; however, the product(s) formed by thiophenol was found to inhibit further formation of hydroperoxide. The maximum concentration of hydroperoxide and gum were about the same for experiments with and without thiophenol; however, the maximum was reached faster for runs with thiophenol. The effects of bulk temperature, and concentration of thiophenol and oxygen on the fouling rate were analyzed using the fouling model developed previously.
Date: December 31, 1995
Creator: Yap, S.; Dranoff, J. & Panchal, C.B.
Partner: UNT Libraries Government Documents Department

Direct chemical oxidation: applications to demilitarization and decontamination

Description: The applicability of using aqueous solutions of sodium peroxydisulfate in the destruction of mustard gas surrogates has been demonstrated. This technique, known as Direct Chemical Oxidation (DCO), resulted in oxidative destruction of these surrogates, and a refinement was added to prevent the formation of slow-to-oxidize intermediates. Specifically, it was shown that `one-armed mustard` gas could be hydrolyzed to thiodiethanol and free chloride ion, and this species could then be partially oxidized to either the sulfoxide or sulfone depending on oxidant stoichiometry. Hydrolysis was accomplished on a mild basic solution at ambient temperature over a number of hours; oxidation was carried out at 90{degrees}C using peroxydisulfate solutions, Partial oxidation of thiodiethanol in the presence of chloride under basic conditions resulted in a a substantially pure mixture of the corresponding sulfone and sulfoxide, with no formation of chlorine gas. Analogous experiments in acid solutions produced a more complex mix of products and some oxidant was consumed in the evolution of chlorine. Complete destruction of the surrogates (to ppm level of detection) was achieved in either acid or base solution with less than a 7-fold excess of oxidant.
Date: April 1, 1998
Creator: Cooper, J.F.; Balazs, B. & Lewis, P.
Partner: UNT Libraries Government Documents Department

Removal of heteroatoms and metals from crude oils by bioconversion processes

Description: The objective of this Cooperative research and Development Agreement project between Oak Ridge National Laboratory (ORNL) and Baker Performance Chemicals (BPC), Chevron, Energy BioSystems, Exxon, UNOCAL and Texaco is to investigate the biological desulfurization of crude oil. Biological removal of organic sulfur from crude oil offers an attractive alternative to conventional thermochemical treatment due to the mild operating conditions afforded by the biocatalyst. In order for biodesulfurization to realize commercial success, reactors must be designed which allow for sufficient liquid/liquid and gas/liquid mass transfer while simultaneously reducing operating costs. To this end we have been developing advanced bioreactors for biodesulfurization and have been studying their performance using both actual crude oil as well as more easily characterized model systems. This CRADA was originally established to be a 3 year program, but was extended to 5 years due to continuing interest. Because of business restructuring, UNOCAL, whose activities focused upon the supply and analysis of crude oil samples, was unable to continue its participation in the CRADA. Hence this report is designed to cover only LTNOCAL`s contribution to the CRADA as other aspects of the research are not yet complete. Experiments investigating the biological oxidative desulfurization of crude oil demonstrated that while dibenzothiophene like structures were readily degraded (>90% in 48 h) this desulfurization had minimal impact upon the total sulfur in the crude oil. This is because these structures represent less than 1% of the total sulfur found in the crude. Additional research is needed investigating sulfur speciation in crude oil with increased efforts upon broadening the sulfur specificity of the biocatalyst.
Date: October 1, 1997
Creator: Kaufman, E.N.
Partner: UNT Libraries Government Documents Department

Two interesting features in the infrared and raman spectra of the 12K organic superconductor {chi}-(ET){sub 2}Cu[N(CN){sub 2}]Br

Description: Two of the larger features in the infrared conductivity spectra of {chi}-(ET){sub 2}Cu[N(CN){sub 2}]Br are analyzed and one is reassigned with the aid of infrared and Raman spectra of isotopically substituted compounds.
Date: December 31, 1995
Creator: Eldridge, J.E.; Xie, Y.; Wang, H.H.; Williams, J.M.; Kini, A.M. & Schlueter, J.A.
Partner: UNT Libraries Government Documents Department

Singlet oxygen and organic light-emitting diodes

Description: The preparation of light emitting diodes employing a new class of materials, 5,10-dihetera 5,10-dihydro-indeno[3,2b]indenes, as hole transport agents is described. These materials have been found to be more resistant to degradation by singlet oxygen than a poly(p-phenylene vinylene) (PPV) derivative.
Date: July 1, 1995
Creator: Jacobs, S.J.; Sinclair, M.B.; Valencia, V.S.; Kepler, R.G.; Clough, R.L.; Scurlock, R.D. et al.
Partner: UNT Libraries Government Documents Department

Electrodeposition on Ni from a Sulfamate Electrolyte Part 1: Effect of a Stress Relief on Annealing Behavior and Film Metallurgy

Description: Ni and Ni alloys are being developed as baseline materials for LIGA technology and prototyping at Sandia National Laboratories. A conventional, additive-free sulfamate electrolyte has been chosen for pure Ni electrodeposition due to its simplicity and ability to produce ductile, low-stress films. When depositing certain Ni alloys, saccharin is typically employed as an electrolyte bath additive. While saccharin is well known and effective as a stress reliever, it has a significant impact on the microstructure of the deposit and its annealing behavior. The electrodeposition of pure Ni in the presence of saccharin is studied here to understand its effects in the absence of an alloying element (such as Co or Fe). The grain structure and Vickers hardness of Ni deposited with and without saccharin on a rotating disk electrode were all found to be consistent with previous studies available in the literature. The following observations were made: (1) The fine, columnar morphology obtained without saccharin became an equiaxed, nano-sized grain structure with saccharin (from {approx}1.5 {micro}m to {approx}40 nm nominal grain size, respectively). The grain refinement resulting from saccharin is not accompanied with an increase in film stress, in contrast to the grain refinement associated with certain Ni alloys. (2) A change in the deposit texture from weak (210) to (111) along the film growth direction with the addition of saccharin. (3) An increase in Vickers hardness by a factor of {approx}2 (from {approx}170 to {approx}320) upon the addition of saccharin. (4) A rapid decrease in hardness with annealing from the high, as-deposited values for films deposited with saccharin to a value lower than that of annealed Ni from an additive-free bath. (5) Accelerated grain growth during annealing for films deposited with saccharin; this has not been observed previously in the literature to the authors' best knowledge.
Date: February 2002
Creator: Kelly, James J.
Partner: UNT Libraries Government Documents Department

Biodesulfurization of water-soluble coal-derived material by Rhodococcus rhodochrous IGTS8

Description: Rhodococcus rhodochrous IGTS8 was previously isolated because of its ability to use coal as its sole source of sulfur for growth. Subsequent growth studies have revealed that IGTS8 is capable of using a variety of organosulfur compounds as sources of sulfur but not carbon. In this paper, the ability of IGTS8 to selectively remove organic sulfur from water-soluble coal-derived material is investigated. The microbial removal of organic sulfur from coal requires microorganisms capable of cleaving carbonsulfur bonds and the accessibility of these bonds to microorganisms. The use of water-soluble coal-derived material effectively overcomes the problem of accessibility and allows the ability of microorganisms to cleave carbonsulfur bonds present in coal-derived material to be assessed directly. Three coals, two coal solubilization procedures, and two methods of biodesulfurization were examined. The results of these experiments reveal that the microbial removal of significant amounts of organic sulfur from watersoluble coal-derived material with treatment times as brief as 24 hours is possible. Moreover, the carbon content and calorific value of biotreated products are largely unaffected. Biotreatment does, however, result in increases in the hydrogen and nitrogen content and a decreased oxygen content of the coal-derived material. The aqueous supernatant obtained from biodesulfurization experiments does not contain sulfate, sulfite, or other forms of soluble sulfur at increased concentrations in comparison with control samples. Sulfur removed from water-soluble coal-derived material appears to be incorporated into biomass.
Date: December 31, 1991
Creator: Kilbane, J. J. II & Jackowski, K.
Partner: UNT Libraries Government Documents Department