Chemistry Commons^™

A Chemical Pathway To The Formation Of Chlorinated Compounds During Combustion, Xiaodong Yang

Masters Theses & Specialist Projects

Two reactions, the Deacon reaction and the chlorination of phenol, which are the postulated starting steps for the formation of chlorinated dioxins during the incineration of the refuse derived fuel, were investigated in this work. Reactions were conducted in a tube furnace, and the products were trapped and analyzed by gas chromatography/mass spectroscopy. It was shown that the Deacon reaction was favored at higher temperatures. The chlorination of phenol in vapor phase was found to begin at temperatures as low as 250°C and to be favored at higher temperatures. The ortho and para positions in the phenol ring are the …

A Study Of The Behavior Of Chlorine And Organic Compounds During Combustion In An Afbc System, Jenny Heidbrink

Masters Theses & Specialist Projects

The purpose of this study is to understand the behavior of chlorine and the emission of organic compounds during combustion in an atmospheric fluidized bed combustion (AFBC) system. Inefficient, uncontrolled use of coal gives rise to organic emissions which can be detrimental to health. The chlorine in coal may cause corrosion problems during utilization, if its concentration is high enough. The method for collection of the emissions of organic compounds involved the use of a Tenax resin as an absorbent for the organic compounds as they were emitted from the combustor. A combined gas chromatography - mass spectrometry (GC-MS) technique …

Degradation Product Analysis Of Bismaleimide Composite, Wendy Zhong

Masters Theses & Specialist Projects

This study evaluates the thermal and oxidative stabilities of a bismaleimide (BMI) polymer composite reinforced with an intermediate modulus graphite fiber, Cytec®5260/IM7. The composite is aged in helium, nitrogen, and air at elevated temperatures up to 600°C. Its weight change is followed thermogravimetrically for stability assessment. The effect of aging gas environment is also studied. The use of on-line gas cell fourier transform IR spectrometer (FTIR) and mass spectrometer (MS) allows for the identification of decomposition products by evolved gas analysis. This combination of thermogravimetric analysis (TGA) and evolved gas analysis by FTIR and MS yields complementary information regarding pyrolysis …

Directed Ortho-Metalation Of The Three Methyl Anisoles In Various Media, Carl Friesen

Masters Theses & Specialist Projects

Directed ortho-metalation (DoM) is a very useful alternative to electrophillic aromatic substitution (EAS) for the synthesis of substituted aromatic compounds. DoM is highly regiospecific providing metalation chiefly in the ortho-position. However, lateral (a-) metalation of an alkyl side-chain and ortho-metalation of a second ortho-position can compete. Investigation of the three methylanisoles was therefore undertaken to determine the interplay between these factors and to discover metalation conditions to achieve selectivity. This goal was uniquely achieved for p-methylanisole where conditions were discovered which allowed > 85% ortho-metalation as determined by GC analysis with virturally no competing lateral metalation. Three derivitives of this ortho-lithio …

A Study Of The Effect Of The Extraction Procedure In The Analysis Of Organic Compounds Adsorbed On Coal Ash, Shobha Purushothama

Masters Theses & Specialist Projects

The organic compounds found adsorbed on coal fly ash have been a cause for concern since the early days of the industrial revolution. A vast majority of the compounds reported as being adsorbed on the ash are polyaromatic hydrocarbons (PAHs). This study represents an attempt to evaluate the parameters involved in the extraction, detection and quantitation of these organic compounds. Though no definite conclusions could be reached as to the most efficient method of extraction, interesting results were obtained with regarding the choice of the solvent and the temperature programming on the GC/MS used for analysis. The solvent of choice …

A Study Of On-Line Analysis Of Hydrogen Chloride Evolution During Coal Combustion, Jennifer Humble

Masters Theses & Specialist Projects

This study involved the use of a thermogravimetric analyzer (TG) interfaced with a fourier transform infrared spectrometer (FTIR) and a mass spectrometer (MS) to determine the evolution of hydrogen chloride from coal during combustion as a function of the chlorine content and mesh size of the coal. It was determined that combined TG-FTIR and TG-MS systems offer the user an efficient means to investigate the mechanism of hydrogen chloride evolution from coal combustion. From the HC1 evolution profiles, it was determined that a good correlation exists between the chlorine content in the coal and the total amount of HC1 evolved. …

Characterization And Catalytic Properties Of Sulfated Zirconia, Melody Bi

Masters Theses & Specialist Projects

Sulfated zirconia has attracted extensive attention due to its superactivity to isomerize alkane and alkenes. Platinum or iron/manganese promoted sulfated zirconia has been shown to increase the reaction rate. These catalysts are normally activated to 650-725°C in air before use. Through on-line analysis of evolved gas species during dynamic heating of the catalysts, some significant information can be obtained concerning the activation mechanism. In the present investigation, combined TG-FTIR, TG-MS and TGDTA techniques were utilized to measure the weight loss of the samples, analyze the evolved gas species and to monitor the phase transformation temperature of the solid. Four samples …

Specification Of Sulfur Forms In Coal, Weihao Wang

Masters Theses & Specialist Projects

Over a century of studies of the organic chemistry of coal has led to many accomplishments in coal chemistry. The recognition of the role that sulfur plays in coal makes the speciation of sulfur in coal one of the most important research goals. In this research solvent extraction, ultimate analysis, FTIR, TG-FTIR, sulfur methylation, and NMR techniques were employed to make quantitative and qualitative determinations of the organic sulfur in coal and its extracts. The data obtained from those methods are discussed with regard to the analytical and synthetic approaches used. Carbon-sulfur bond cleavage at room temperature was observed during …

Icp Analysis Of Solids/Waste Slurries, Buqian Wang

Masters Theses & Specialist Projects

The direct injection of solids/water slurries into an inductively coupled plasma (ICP) spectrometer offers a rapid and easy method for the analysis of major, minor, and trace elements in coal, coal ash, cements, and refractory materials. In this study aqueous slurries of 6 coals were prepared by milling with a stirred-ball slurry attritor mill and an air impact pulverizer. ICP analysis values obtained for the six coals by the two different grinding methods were compared. Five coal ashes and five check standard reference materials were ground by an attritor mill and analyzed with an ICP spectrometer. Slurries of standard reference …

Controlled Oxidation Studies Of Coal/Refuse Fuel Blends, Aiping Wu

Masters Theses & Specialist Projects

A study of the controlled combustion of blends of biomass materials and coals was conducted. Crushed limestone was added to the blends as an absorbent for sulfur oxides. The samples were combusted in quartz-fiber crucibles in a forced air furnace. Combustion at different times and temperatures were studied. The amount of carbon, hydrogen, and sulfur in the residues, as well as the amount of ash formed, were used as measures of combustion efficiency. The optimum temperature for combustion of most blends was found to be in the 700 - 800°C range. A study of methods for determining the amounts of …

Electrochemical Detection Of Aliphatic Sulfur Compounds In Liquid Coal Extracts, Samuel Myers

Masters Theses & Specialist Projects

The presence of sulfur compounds in coal is a serious environmental problem that affects the coal industry. This problem is due to the fact that organic sulfur is not separated or removed during any physical cleaning process. Organic sulfur is removed only during a more costly chemical desulfurization process. The kinds of organosulfur compounds in coal are generally known, but the quantity of each type of compound and the distribution of these compounds throughout the coal matrix has not been studied extensively. The objective of this research was to investigate the more reactive and chemically labile organosulfur compounds in liquid …

The Effects Of Chlorine On Boiler Corrosion, Marian Upchurch

Masters Theses & Specialist Projects

The amount of corrosion of six metal samples was measured by a change in weight over time. The simulated flue gas stream consisted of 0.2% SO2,14% C02 / and 4% O2, with the HC1 percentage varied from 0.2% to 0.0% and the balance of gas being N2. A Lindbergh Three Temperature Tube Furnace was used to house the metal samples at 100°C, 200°C, and 600°C while being subjected to the simulated flue gas stream. The six metal samples were chosen on the frequency of industrial use. Two carbon steels, C1018 and C1010, contain no chromium and were chosen because of …

Coal Sulfur Forms Determination Using Thermal Analysis Methods, Bucheng Wang

Masters Theses & Specialist Projects

By optimizing parameters including temperature, reaction time, reagent concentration and pressure, the optimum conditions for the mild oxydesulfurization of coals were determined to be 150°C-200"C and 10 atmospheres oxygen in aqueous slurries of coal reacted with 1 M NH₄OH for 1.5-2 hours. The total amount of sulfur removed from -60 mesh coals ranges from 51% to 78% with a mean of 64%, while the amount of inorganic sulfur removed from the coals ranged from 66% to 91% with a mean of 77%. The amount of organic sulfur removed from the samples ranged from 36% to 50% with a …

The Development Of New Methods For Coal Sulfer Forms & Sulfur In Ash Determination, Robert Forsythe

Masters Theses & Specialist Projects

The development of new procedures to determine the amount and/or types of sulfur in coal and coal products is an ongoing process for coal scientists This development is driven by the problems and inconveniences of the current ASTM methods In this thesis, the work done at Western Kentucky University in the development of two new sulfur determination procedures will be described. The first procedure can be used as an alternative method for coal sulfur forms analysis with results comparable to the ASTM method. This procedure involves heating the coal samples at 365°C and 440°C for thirty minutes to selectively remove …

Thermal Analysis Of Bismaleimide/Graphite Fiber Composite By Tg/Ftir, Qi Zhang

Masters Theses & Specialist Projects

The purpose of this project was to study the thermal and oxidative stability of a specific polymer composite. A TG/FTIR combined technique was employed to characterize this polymer/graphite fiber composite. The polymer composite sample was decomposed in nitrogen, air, and 3% oxygen atmospheres in a Seiko thermogravimetric analyzer. The use of a gas cell Fourier-transform IR spectrometer downstream from the TGA allowed for the identification of evolved gas products.

The thermal oxidative stability (TOS) of this composite was compared to its thermal stability. Also, comparison of the TOS in different atmospheres was made. In addition, the effects of specimen geometry …

Characterization Of Combustion Profiles Of Co-Fired Coal/Biomass/Limestone Samples By Tg And Tg/Ftir, Erik Jon Hutchinson

Masters Theses & Specialist Projects

Recent concerns over declining landfill space and a renewed interest in waste-to-energy technologies have increased the possibilities of co-firing different types of fuels in fluidized bed combustion systems. Fluidized bed combustion systems are idea for co-firing because of their ease in heat conversion and ability to burn a wide range of fuels. Additionally, thermal analytical techniques can be used to screen fuel blends for the fluidized bed combustion systems at a lower cost than directly firing the fuel blends in pilot systems. Three coals, three different municipal solid wastes (MSW), one limestone were combined into nine series of binary fuel …

Examination Of Fat Oxidation Products By Ft-Nmr & Ft-Ir, De Chen

Masters Theses & Specialist Projects

Edible oils are easily oxidized when used for frying. Oxidation originates with double bonds present in unsaturated fatty acids. A new NMR method is presented which offers potential for determining the products of oil oxidation. High resolution fourier transform nuclear magnetic resonance (FT-NMR) and fourier transform infrared (FT-IR) spectroscopy have found increasing use in biochemistry. One pure fat, trioleoylglycerol, was heated at 160°C in the presence of air Samples were taken for FT-NMR and FT-IR analyses at 4, 10. 20. 25, 35, 50, 70 and 100 hours. Proton, Carbon-13 and several types of two-dimensional FT-NMR spectra were obtained using a …

Behavior Of Chlorine & Sulfur During Coal Pyrolysis & Combustion, Dakang Shao

Masters Theses & Specialist Projects

The behavior of chlorine and sulfur in Illinois coals and during pyrolysis and combustion their forms in the coals were evaluated by combined Thermogravimetry/Fourier Transform Infrared Spectroscopy/ Ion Chromatography (TG/FTIR/IC) techniques. It was found that more than 90% of chlorine in Illinois coals was liberated as HC1 gas during pyrolysis and combustion in the temperature range of approximately 3000 - 600°C, with the amount reaching the maximum around 440°C. Similarity of the HC1 and NH3 release profiles during pyrolysis of IBC-109 indicates that the forms of chlorine in coal is associated closely with the forms of nitrogen, and that the …

Nmr Analysis Of Sulfur Compounds In Petroleum, Kanning Wu

Masters Theses & Specialist Projects

The speciation and quantification of organic sulfur forms in fossil fuel is an area of research. This thesis describes an NMR method which offers potential for identifying and possibly quantifying both nonvolatile and volatile sulfur forms in fossil fuels. The method is based on the methylation of sulfur compounds to form methyl sulfonium salts:

RSR + Ch₃I --> (R₂S+-Ch₃)I^~

We propose to apply this chemistry to the analysis of sulfur functions in fossil fuels. The sulfur functions are methylated using ¹³C-enriched methyl iodide. The products are then analyzed by ¹³C NMR …

Development Of Hplc-Ec Methodology & Its Use In The Determination Of The Daily Pattern Of Brain Octopamine Levels In Leucophaea Maderae, Maya Siddiqui

Masters Theses & Specialist Projects

A solid phase extraction technique was developed to aid in removing interfering substances from the cockroach brain extract. Quantitative analysis of octopamine was subsequently achieved by HPLC with amperometric electrochemical detection. The procedure affords 80 to 100 percent recovery of octopamine. The presence of octopamine in brain extract was confirmed by GC-MS.

The daily pattern of brain octopamine levels in cockroach Leucophaea maderae was investigated using the HPLC-EC assay procedure. It was concluded that the concentration of brain octopamine in the cockroach L. maderae does not exhibit daily rhythm.

The Palladium (Ii) –Catalyzed Homogeneous Oxidation Of 1-Hexene, Margarita Kirova

Masters Theses & Specialist Projects

The Palladium(II)-catalyzed homogeneous oxidation of 1-hexene in methanolic medium has been studied, copper(II) chloride being used as cocatalyst. Aspects of the kinetics, mechanism and product composition were investigated in several series of oxidations involving variation of hexene concentration, oxygen partial pressure, Cu(II): Pd(II) ratio and concentration and temperature. The progress of the reaction was studied in the course of periodic sampling runs. Reaction products were identified by gas chromatography, and verified by means of GC/mass spectrometry. The expected product of 1-hexene oxidation was 2-hexeanone: however, 3-hexanone occurs as a major coproduct, arising from concurrent Pd(II)-catalyzed isomerization of 1-hexene to 2-hexene. …

Thermal Analysis Of Milkweed Floss Using Tg/Ftir, Pei Gu

Masters Theses & Specialist Projects

The thermal analysis of milkweed and several individual commercial samples of .similar chemical composition has been carried out. By combining a two-stage thermal process. (pyrolysis-combustion) with TG-FTIR, it has been possible to identify the major organic volatile products during pyrolysis and to correlate gas evolution with the decomposition of the individual components (cellulose, hemicellulose and lignin) of the floss. During pyrolysis, acetic acid, formic acid and methanol are formed 1n addition to CO2, and H2O. The data also show that pyrolytic decomposition of the three chemical constituents of milkweed occur without any apparent synergistic interaction. The combustion of …

Thermal Properties Of Some Lipid Components Of Cell Membranes, Lihua Wei

Masters Theses & Specialist Projects

Phospholipids are the major structural components of the lipid portion of biological membranes. The study of the thermal properties of these phospholipid provides a systematic understanding of the relationships between the chemical structures and functional properties of phospholipid molecules in artificial and biological membranes. This study examined the thermal behavior of phospholipids in the solid state using DSC and TG coupled with FITR. The phospholipids were found to have phase transitions below the melting point. Egg-yolk lecithin had four transitions below its melting point; sphingomyelin had two phase transitions below its melting point. Phosphatidylethanolamine and phosphatidylserine had complex phase transitions. …

Evolved Gas Analysis Using Coupled Tg-Cg & Tg-Ftir, Keith Bradfield

Masters Theses & Specialist Projects

Thermal analysis methods have ben used for many years for material characterization. In recent years, thermal methods have been coupled to other methods of chemical analysis to obtain more complete material characterization. This study looks at thermal decomposition of polymer samples as well as coal samples in atmospheres of nitrogen and air. The thermal analysis instrument used was coupled to a Gas Chromatograph (GC) and a Fourier Transform Infrared Spectrometer (FTIR) so that the gaseous products evolved during thermal decomposition could be analyzed. The results obtained show that the coupled techniques of TG -GC and TG-FTIR can show pyrolysis and …

Part I: Oxidation Of Heavy Metal Sulfides In Relation To The Environment; Part Ii: Fundamental Theory & Experiments Concerning Gas Chromatography & Mass Spectrometry, Judith Morgan

Masters Theses & Specialist Projects

Oxidation of heavy metal sulfides is a thermodynamically spontaneous process. Because of this, metal sulfides in the presence of oxygen are not stable. Currently there are over 100 streams and rivers, within the U.S., contaminated with heavy metal mine drainage; therefore an approved method of restoration is necessary. Precipitation of heavy metals as sulfides using H₂S as a reductant has been favorably reviewed as a restorative technique to clean up mining areas. However, using this technique on the laboratory scale does not prove to be a viable answer and shows strong pH dependence.

In the past three years …

Reductive Chemistry Of Dicyanoalkane Reactive Intermediates, Beshakeh Fonkeng

Masters Theses & Specialist Projects

Radical ions are reactive intermediates that are both radicals and ions (either a radical cation or a radical anion). The intrinsic properties of radical ions are not yet well -characterized. Such knowledge is mechanistically important to the organic chemist.

The specific question that motivates this research is as follows: is it possible to controllably express free radical processes in a radical ion independent of ionic chemistry (and vice versa) and, if so, what factors dictate which type of chemistry is expressed?

Our investigation focused on the chemistry of radical anions of dicyanoalkanes that are formed upon metal reduction. Factors influencing …

Measuring Δh Using Dsc, Tga & Dta, Roland Hoffman

Masters Theses & Specialist Projects

The purpose of this study was to obtain greater accuracy in the measurement of the heat of reaction by combining data from various thermal analysis techniques. Conventional equations that calculate heat of reaction are limited because they do not take in to account mass change. Therefore, an enhanced equation was developed to integrate mass (weight) change to provide greater accuracy. The path chosen to implement this new equation employed simultaneous Thermogravimetric / Differential Thermal Analysis (TG/DTA) that could provide both ΔT and weight data simultaneously. Computer programs were written in C and Pascal languages to provide communication capabilities between computers …

Air Oxidation Of A Soluble Coal Extract, Douglas Kimbler

Masters Theses & Specialist Projects

The effects of air oxidation on coal may change many important attributes of the coal such as calorific values, solubilities and solvent swelling values. By studying the effects of air oxidation on the soluble portion of coal, we were able to study coal oxidation in a new light.

Thermogravimetric Analysis Of Coal Blends Under Conditions Of Pyrolysis & Combustion, Yaodong Gan

Masters Theses & Specialist Projects

In recent years, the growing attention to coal quality by coal-burning utilities has led to an increase in coal blending. Coal blending is done with both economics and the quality of coal in mind. To assess the quality of coal, pyrolysis and combustion influencing thermal parameters, as measured in thermogravimetric analysis (TGA) experiments can be applied. The coal industry needs a study to determine relationships that may exist between the measured values of TGA thermal parameters in individual coals and those in the blends. The TGA thermal parameters are the weight loss, T_max, T_i, T_{1/2 …}

A Study Of The Flammability Of Chlorinated Polyethylene By Thermal Analysis, Michele Whitely

Masters Theses & Specialist Projects

High Density Polyethylene (HDPE) is a highly flammable compound. Finding a method to reduce HDPE's flammability is of great scientific interest to researchers and industry. Chlorination of the HDPE has been shown to have an effect on the flammability of the polymer. This study looks at the effects of various chlorinated samples on the thermal decomposition of HDPE in atmospheres of nitrogen, air, and oxygen. The thermal analysis instruments used were a Thermogravimetric Analyzer (TGA), and a Differential Scanning Calorimeter (DSC). To study the gaseous products evolved during thermal decomposition of the polymer Fourier Transform Infrared Spectrophotometry (FTIR) and Gas …