The purpose of this investigation was to study the effect of the direction of flow with varying phase velocities on the overall, mass-transfer coefficient in a horizontal, unpacked, extraction tube, for the system n-butanol-water, and for the system 1,1,2-trichloroethane-sectione-water. / Master of Science

Chlorinated solvents are among the most prevalent contaminants at Superfund sites. Perchloroethylene (PCE) and its degradative byproducts pose a particular problem because of their persistence in the subsurface and their threat to ecological health. In this study, microcosms were used to test the viability of bioaugmentation as a possible remediation strategy at a PCE contaminated site at the Naval Amphibious Base at Little Creek located in Virginia Beach, Virginia. All microcosms were created in duplicate using spatially diverse soils and the bioaugmented series innoculated with a mixed microbial culture provided by the Dr. Frank Loffler. This culture has been found to be capable of completely degrading PCE to ethene. The aqueous ethene concentration was monitored over time. It is clear from the results that bioaugmentation successfully increased the degree of reductive dechlorination over their static counterpart. Without innoculation, shallow static microcosms showed an accumulation of cis-DCE, while deep soils never showed conversion beyond TCE. Shallow bioaugmented microcosms showed the production and loss of vinyl chloride indicated probable complete conversion of PCE to ethene while deep soils showed the production of cis-DCE. These differences in dechlorination between shallow and deep soils indicate a possible disparity in reduction capacity. At day 78, microcosms were spiked with higher concentrations of PCE resulting in a reduction in dechlorination activity. Static microcosms exhibited similar degradative trends but bioaugmented batches experienced dramatic reductions in dechlorination activity indicating possible inhibition effects of native organisms due to concentration or potential toxic shock. It appears that bioaugmentation is a remediation alternative worthy of further study including possible delivery methods, toxicity or inhibition effects of concentration, and fate/transport studies. / Master of Science

Thesis (Ph. D.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on February 6, 2007). Thesis advisor: Timothy G. Rials. Vita. Includes bibliographical references.

The implementation of sustainable solvents and processes is critical to new developments in reducing environmental impact, improving net efficiency, and securing economic profitability in the chemical and pharmaceutical industries. In order to address the challenge of sustainability, researchers have used switchable solvents for both reaction and separation by utilizing a built-in switch to undergo a step change in chemical and physical properties. This allows us to facilitate reactions in the solvent then activate the switch to enable separation and facile product recovery. Subsequently, we can recover the solvent for reuse and avoid energy- or waste-intensive separation processes; thus we are developing and using these switchable solvents as sustainable and environmentally benign alternatives to traditional processes. In this research, we enable the sustainable scale-up of a switchable solvent - piperylene sulfone - a "volatile" and recyclable DMSO replacement. In the development of this process, we improved the reaction performances and developed a green purification method. Furthermore, we enable and demonstrate the implementation of a Meerwein-Ponndorf-Verley (MPV) reduction, a pharmaceutically relevant reaction, into a continuous flow platform. The innovation of continuous flow processes can replace traditional batch reaction technology, and is indeed a key research area that has been acknowledged by the pharmaceutical industry. Additionally, we utilize the switchable sulfone solvents, piperylene and butadiene sulfone, for reaction and separation of HMF produced from monosaccharides as an alternative to a process which has been limited by an inefficient separation step.

Thesis (Ph. D.)--School of Dentistry and Dept. of Chemistry. University of Missouri--Kansas City, 2004. / "A dissertation in oral biology and chemistry." Advisor: J. David Eick. Typescript. Vita. Description based on contents viewed Feb. 23, 2006; title from "catalog record" of the print edition. Includes bibliographical references (leaves 137-145). Online version of the print edition.

Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-09T00:59:56Z (GMT). No. of bitstreams: 1 Navarro_FabianaMariaSalvador_D.pdf: 9206706 bytes, checksum: 57151816223e7adf0ae76b5ee6685196 (MD5) Previous issue date: 2007 / Resumo: O óleo de farelo de arroz tem sido considerado como um óleo superior devido às suas características químicas, sendo equiparável aos óleos de soja, milho e algodão. O óleo do farelo de arroz é rico em vitaminas, apresenta baixa incidência de ingredientes responsáveis pelo colesterol e alto teor de tocoferóis (vitamina E) que garantem uma alta estabilidade, retardando a rancidez e o aparecimento de sabores indesejáveis. Dentre os diversos meios conhecidos para extração do óleo de sementes oleoginosas, o mais comumente utilizado é o de extração por solvente, sendo o hexano utilizado para este fim. A desacidificação de óleos vegetais por extração líquido-líquido tem-se mostrado como rota alternativa na obtenção de óleos vegetais com teores aceitáveis de ácidos graxos livres. A razão para a utilização deste novo processo está no fato de consumir menor quantidade de energia, pois é realizado a temperatura ambiente e pressão atmosférica. Neste contexto, o presente trabalho tem como objetivo estudar a variação das razões solvente/óleo durante o processo de extração líquido-líquido na desacidificação do óleo de farelo de arroz, bem como da variação da solução de solventes utilizados no mesmo. Os resultados obtidos no presente trabalho permitiram concluir que a razão 10:1 solvente etanol/óleo apresentou os melhores resultados na extração líquido-líquido, pois consome menor quantidade de solvente e tempo de processo resultando em um pequeno percentual de ácido graxo livre no óleo de farelo de arroz, conseqüentemente em uma grande quantidade de remoção. E que apesar de se utilizar soluções de solventes (1:1 metanol/etanol e 1:1 isopropílico/etanol) à razão de 10:1 solvente/óleo na desacidificação do óleo de farelo de arroz durante o processo de extração líquido-líquido, estes não apresentaram resultados maiores ou mais significativos do que quando se utiliza somente o etanol como solvente / Abstract: The oil of rice bran has been considered as superior oil which had its chemical characteristics, being similar to oils of soy, com and cotton. The oil of the rice bran is rich in vitarnins, presents low incidence of responsible ingredients for the cholesterol and high leveI oftocopherols (vitamin E) that they guarantee a high stability, being late the rancidity and the appearance undesirable of flavors. Amongst the diverse ways known for extraction it oil of oilseeds, the most used is of extraction for solvent, being the hexane used for this purpose. The vegetal oil deacidification for liquid-liquid extraction has revealed as altemative way in the vegetal oil attainrnent with acceptable of free fatty acid. The reason for the use of this new process is in the fact to consume minor quantity of energy; therefore it is submitted the ambient temperature and atmospheric pressure. In this context, the present work has as objective to study the variation of the rations solventloil during the liquid-liquid extraction process in the deacidification of the rice bran oil, as well as the variation of the solvent solution used. The results gotten in the present study had allowed to conclude that the ration 10:1 solvent ethanol/oil presented the best ones result in the liquid-liquid extraction, because consume minor quantity of solvent and process time, resulting in a small percentage of free fatty acids in the rice bran oil, obtaining a bigger quantity of removal. Although to use solvents solutions (1: 1 methanol/ethanol and 1:1 isopropanol/ethanol) 10:1 solventloil in the rice bran oil deacidification during the liquid-liquid extraction process, these had not presented bigger or more significant results then that when ethanol is used alone as solvent. Keys Words: extraction liquid-liquid; deacidification; rice bran oil / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Capítulo 1. Adiciones Michael asimétricas organocatalizadas en líquidos eutécticos. Siguiendo los principios de la “Química Verde” se desarrolló un sistema catalítico basado en disolventes eutécticos y organocatalizadores quirales derivados de 2-amino benzimidazol. Este nuevo sistema fue empleado para catalizar la adición enantioselectiva de compuestos de 1,3-dicarbonílicos a β-nitroestirenos. El procedimiento evita el uso de disolventes orgánicos volátiles tóxicos como medio reacción, proporcionando acceso a moléculas quirales altamente funcionalizadas de forma selectiva y eficiente. Además, la reacción puede realizarse a una escala de gramos y a su vez este sistema catalítico es fácilmente reciclable y reutilizable durante cuatro ciclos, lo que da lugar a un procedimiento limpio, económico, sencillo y escalable que cumple la mayoría de los criterios necesarios para ser un proceso medioambientalmente benigno y sostenible. Los estudios de RMN realizados a la mezcla organocatalizador-líquido eutéctico han confirmado el papel clave de los enlaces de hidrógeno entre el disolvente y el organocatalizador quiral, que permiten su recuperación y la reciclabilidad del sistema. Capítulo 2. α-Aminación electrofílica asimétrica organocatalizada en líquidos eutécticos. Empleando el sistema catalítico basado en el uso de catalizadores quirales de 2-benzoimidazol y líquidos eutécticos se realizó la α-aminación enantioselectiva de compuestos de 1,3-dicarbonílicos. Con este procedimiento, se evita el uso de compuestos orgánicos volátiles tóxicos como medios de reacción. Las moléculas quirales altamente funcionalizadas sintetizadas, que son importantes en la síntesis de productos naturales, se sintetizaron mediante un protocolo eficiente y estereoselectivo. Además, la reacción puede llevarse a cabo para la síntesis de un gramo de producto, siendo posible el reciclaje del sistema catalítico durante al menos cinco ciclos de reacción consecutivos. Este procedimiento representa un método barato, simple, limpio y escalable que cumple con la mayoría de los principios para ser considerado un proceso medioambientalmente benigno y sostenible. Capítulo 3. Líquidos eutécticos quirales. Diferentes mezclas eutécticas basadas en prolina fueron empleadas en la adición Michael asimétrica de cetonas sobre nitroalquenos. En vista de los resultados, y los estudios de 1H-RMN realizados, se confirmó una relación entre la conversión y selectividad del proceso con la constante asociación de los componentes de la mezcla eutéctica. Con estos datos un nuevo disolvente eutéctico quiral a base de bromuro de (S)-N,N,N,-trimetil-1-(pirrolidin-2-il)-metanamina y glicerol fue diseñado y sintetizado con éxito. Este sistema catalítico se mostró eficiente en la adición Michael de ciclohexanona a β-nitroestirenos, obteniendo selectividades moderadas en condiciones suaves. El sistema catalítico eutéctico fue recuperado fácilmente y reciclado hasta cinco veces en la adición de ciclohexanona a β-nitroestireno sin pérdida significativa de actividad catalítica.

The purpose of this dissertation is to investigate the thermochemical properties of nonelectrolyte solutes dissolved in ternary solvent mixtures, and to develop mathematical expressions for predicting and describing behavior in the solvent mixtures. Forty-five ternary solvent systems were studied containing an ether (Methyl tert-butyl ether, Dibutyl ether, or 1,4-Dioxane), an alcohol (1-Propanol, 2-Propanol, 1-Butanol, 2-Butanol, or 2-Methyl-1-propanol), and an alkane (Cyclohexane, Heptane, or 2,2,4-Trimethylpentane) cosolvents. The Combined NIBS (Nearly Ideal Binary Solvent)/Redlich-Kister equation was used to assess the experimental data. The average percent deviation between predicted and observed values was less than ± 2 per cent error, documenting that this model provides a fairly accurate description of the observed solubility behavior. In addition, Mobile Order theory, the Kretschmer-Wiebe model, and the Mecke-Kempter model were extended to ternary solvent mixtures containing an alcohol (or an alkoxyalcohol) and alkane cosolvents. Expressions derived from Mobile Order theory predicted the experimental mole fraction solubility of anthracene in ternary alcohol + alkane + alkane mixtures to within ± 5.8%, in ternary alcohol + alcohol + alkane mixtures to within ± 4.0%, and in ternary alcohol + alcohol + alcohol mixtures to within ± 3.6%. In comparison, expressions derived from the Kretschmer-Wiebe model and the Mecke-Kempter model predicted the anthracene solubility in ternary alcohol + alkane + alkane mixtures to within ± 8.2% and ± 8.8%, respectively. The Kretschmer-Wiebe model and the Mecke-Kempter model could not be extended easily to systems containing two or more alcohol cosolvents.

The focus of this research was to improve the sustainability of various processes by employing tunable solvents, switchable solvents, and catalysis. In Chapter 2, we report applications of tunable solvents to metal and enzyme catalyzed reactions of hydrophobic substrates. Tunable solvents are defined as solvent that change properties rapidly but continuously upon the application of an external physical stimulus and we utilize these solvents to couple homogeneous reactions with heterogeneous separations. We developed organic-aqueous tunable solvents that utilize propane for efficient phase separation at moderate pressures around 1 MPa; for example the water contents in the propane-expanded THF is 3 wt% at 0.8MPa at 30°C. Also, we extended the use of CO2-organic-aqueous tunable solvents to a pharmaceutically-relevant reaction--the hydroformylation of p-methylstyrene. The homogeneous reactions provide fast rates with excellent yields. At 60°C, the reaction reaches completion after 180 minutes with 95% branched aldehyde yield. The CO2-induced heterogeneous separation of the product from the catalyst provides an efficient and simple way to remove 99% of the product, to retain 99.9% of catalyst, and to recycle the Rh-TPPMS catalyst for five consecutive reactions. In chapter 3, we investigated the use of reversible ionic liquids (RevILs) for synthesis of nanoparticles. RevILs are formed by the reversible reaction of compounds with basic nitrogen functionalities (molecular liquid) with CO2 at ambient pressure to form a liquid salt (ionic liquid). We demonstrated that RevILs form microemulsions that can be switched-on by bubbling CO2 and switched-off by heating. These microemulsions solubilize ionic compounds such as chloroauric acid. We utilized these microemulsions as a template for controlled synthesis of gold nanoparticles. With 2-component RevILs, [TMBGH]+[O2COCH3]-/N-propyl-octylsulfonamide/hexane were used to form particles in the size range of 6-20 nm with an average particles size of 11.4±3.3. With 1-component RevILs, (3-aminopropyl)-tripropylsilane was used to prepare semi-spherical gold particles with an average size of about 20nm. The 1-component RevILs systems provide a simpler method to form microemulsions when compared to the 2-componenet RevILs systems since they eliminate the need for alcohols and surfactants. In chapter 4, we developed a catalyst that efficiently decomposes hydrazine to selectively produce ammonia. This enables the use of the chemical propulsion hydrazine for electric propulsion as well. We prepared nickel, copper, cobalt, ruthenium, rhodium, and iridium nanoparticles that were supported on silica and we tested these silica-supported metals for the decomposition of hydrazine. To study the catalytic activity, we designed and constructed a continuous flow reactor. The results show that nano-nickel supported on silica is the most active and selective catalyst with 100% conversion of hydrazine and 94±3% yield of ammonia.

L(objectif de cette thèse a été de développer de nouveaux solvants d'absorption des composés organiques volatils (COV). Ces derniers sont des polluants atmosphériques primaires généralement utilisés comme solvants et émis directement par les industries. Ils induisent des effets nocifs pour la santé, et certains d'entre eux, sont classés comme cancérogènes. La réduction des émissions de ces polluants reste donc une préoccupation majeure. L'objectif de notre travail a été d'évaluer les solvants eutectiques profonds (DES) comme absorbants pour les COV. Les DES représentent une nouvelle génération de solvants. Ils sont formés par simple mélange de 2 ou plusieurs composés. Ils peuvent être produits à partir de composés économiques, naturels et biodégradables. La préparation de ces solvants est facile et permet une économie d'atome de 100%. Le travail a été divisé en trois parties.La première partie a été consacrée à la caractérisation des propriétés physico-chimiques des DES, telles que la densité et la viscosité. L'analyse des spectres infrarouge des DES et de leurs composés purs a montré une implication des liaisons hydrogène dans la formation des DES. La polarité a été étudiée à l'aide de la sonde Nile red. Enfin, la solubilité de gaz (CO₂, CH₄ and Ar) a été mesurée dans les DES en fonction de la température. La deuxième partie a porté sur l'évaluation de la capacité d'absorption des DES en utilisant la technique d'headspace statique couplée à la chromatographie en phase gazeuse. Ceci nous a permis de déterminer le coefficient de partage gaz/liquide pour les COV dans les DES à différentes températures. L'influence des mélanges de COV sur les capacités d'absorption des DES a été également déterminée. Ces derniers ont montré des capacités d'absorption élevées pour la variété de COV, sans saturation même à forte concentration. Un nouveau système DES-cyclodextrine a également été évalué. Les capacités d'absorption ont été améliorées grâce au rôle de molécule cage de la cyclodextrine. La deuxième partie a été tournée vers l'application industrielle. Nous avons évalué les capacités d'absorption des DES à l'aide d'un montage dynamique qui simule une colonne d'absorption industrielle. Cette installation permet de moduler le débit du COV, les teneurs en eau ainsi que la température de la colonne. Enfin, la régénération des DES a été effectuée par plusieurs cycles absorption/désorption sans perte de capacité d'absorption. En conclusion, l'ensemble des résultats obtenus a montré que les DES possédaient de nombreux atouts leur permettant d'être considérés comme des solvants prometteurs pour l'absorption des COV. / The aim of this thesis was to develop new solvents for the absorption of volatile organic compounds (VOC). VOC are primary air pollutants generally used as solvents and emitted directly from industries. They have adverse health effects and some of them are classified as carcinogenic. Consequently, the reduction of the emissions of these pollutants remains a major challenge to reduce air pollution. Hence, our objective was to evaluate deep eutectic solvants (DES) as absorbents for VOCs. DESs represent a new generation of solvents that is formed by simply mixing two or more compounds. They can be produced from cheap, natural and biodegradable compounds. The preparation of these solvents is easy and is 100% atom efficient. This work was divided into three parts.The first part focused on the physicochemical properties of DES, such as density and viscosity. Analysis of the infrared spectra of DES and their pure compounds showed that hydrogen bonds are essential for the formation of DES. Their polarity was studied using the Nile red probe. In addition, solubility of various gases (CO₂, CH₄ and Ar) was measured as a function of temperature. The second part dealt with the evaluation of the aborsption capacity of DESs using static headspace coupled with gas chromatography. The determination of gas/liquid partition coefficient was performed for various VOC and DES at different temperatures. In addition, the influence of VOC mixtures on DES absorption capacities was determined. DES showed high absorption capacities for a variety of VOCs, without saturation even at high concentration. A new DES-cyclodextrin system was developed and showed improved absorption capacities due to the complexation ability of the cyclodextrin. The last part was oriented towards the industrial application of DESs. The absorption capacities of DESs were evaluated using a dynamic set-up which simulated an industrial absorption column. This set-up allows the modulation of the VOC flow rate, water content and column temperature. Finally, the regeneration of the absorbent was carried out by several absorption/desorption cycles without loss of absorption capacity. In conclusion, the overall results showed that DES have characteristics that allow them to be considered as promising solvents for VOC absorption.