The pure sodium salts of the toluenesulfonic acids were prepared by one of two ways. Both methods started with diazotization of the toluidine. In the first method, the diazonium solution was treated with sulfur dioxide and copper powder, and the resulting sulfinic acid was oxidized to the sulfonic acid with potassium permanganate. In the second method, the diazonium solution was treated with cuprous chloride and sulfur dioxide to give the sulfonyl chloride which was hydrolyzed to the sulfonate. Toluene was sulfonated by SO3 (enriched with S-35) in refluxing SO2 solution. The isotope dilution technique was used to determine the isomer distribution as 5.6 ± 0.6% ortho, 9.7 ± 0.4% meta, and 84.8 ± 1% para. A mixture of benzene and toluene was sulfonated as before, and the isotope dilution technique was employed to give the rate of sulfonation of toluene relative to that of benzene as 25 ± 7. This value with the isomer distribution gave partial rate factors in the sulfonation of toluene as of 4.2, mf 7.3, and pf 127. Some a-anilinoketones were prepared starting with the appropriately substituted benzaldehydes. The benzaldehyde was condensed with nitroethane to give a 1-phenyl-2-nitropropene, which was treated with acid and iron powder to give the phenylacetone. The phenylacetone was brominated in acetic acid and the resulting a-bromophenylacetone was treated with the appropriately substituted aniline to give the a-anilinophenylacetone. The anilinoketones prepared in this manner were 1-(4-chloroanilino)-1-(4-chlorophenyl)-2-propanone, its dibromo analog, and 1-(3-chloroanilino)-1-(3-chloropbenyl)-2-propanone. These anilinoketones were subjected to rearrangement conditions: refluxing ethanol, refluxing ethylene glycol, ethylene glycol heated at 105° by a refluxing toluene bath, or ethylene glycol heated at 150° by a refluxing bromobenzene bath, with γ-picoline hydrobromide as catalyst. No rearrangement was detected (ultraviolet analysis) in any of the conditions used in this work. The kinetics of the addition of bromine to cyclohexene in dichloromethane solution was studied at 0° and -22.9° using vacuum line techniques. The product was shown to be trans-1, 2-dibromocyclohexane by comparison of physical constants found with those in the literature and by use of a gas chromatograph. The order of the reaction as determined by the differential method was found to be 1.7 at 0° and 1.4 at -22.9°. The rate constants were calculated to be 80 ± 16 liter 0.7/mole 0.7 sec. at 0° and 48 ± 9 liter 0.4/mole 0.4 sec. at -22.9°. These results indicate a complex system with competing reactions. A possible mechanism is suggested as a explanation for the results.

No description available.

La synthèse et la caractérisation de nouvelles membranes à conduction protonique, pour pile à combustible à membrane échangeuse de proton, ont été réalisées. Une étude sur des molécules modèles a permis de mieux appréhender la stabilité thermique et électrochimique du polyéthersulfone sulfoné (S-PES). Des membranes à base de polyéthersulfone sulfoné greffés à l’octylamine (S-PESOS) et des membranes mixtes à base de S-PESOS et S-PES ont été caractérisées d’un point de vue physicochimique et électrochimique. L’effet de la réticulation chimique sur les propriétés des membranes a été évalué. Les membranes réticulées présentent des bonnes propriétés mécaniques, des conductivités ioniques et une stabilité chimique suffisantes pour être utilisées dans les piles à combustible à membrane échangeuse de proton. L’étude des propriétés de transport dans ces électrolytes acides a été approfondie en corrélant des mesures thermiques avec des mesures électrochimiques, thermodynamiques et les performances en pile. Mots clés: pile à combustible à membrane échangeuse de proton, conductivité ionique, taux de sulfonation, polyéthersulfone. / The synthesis and characterizations of new membranes with for proton exchange membrane fuel cell were carried out. Thermal and electrochemical stability of sulfonated polyethersulfone (S-PES) were studied. Sulfonated polyethersulfone grafted with octylamine (S-PESOS) membranes and binary S-PESOS and S-PES membranes were characterized from a physicochemical and electrochemical point of view. The effect of chemical cross-linking on the membrane properties was evaluated. The cross-linked membranes showed sufficient mechanical properties, ionic conductivities and chemical stability to be used as electrolyte in the proton exchange membrane fuel cell. The proton transport mechanisms, in this acid electrolyte, were deepened correlating thermal and electrochemical properties, thermodynamic measurements and fuel cells performances.

No description available.

The dioxin receptor (DR), a transcription factor with basic-helix-loop-helix/PERARNTSIM (bHLH/PAS) homology domains, is activated by toxic xenobiotic ligands leading to severe physiological disturbances most of which are due to deregulation of receptor’s central role in normal development. Activation mechanisms of DR in the presence of exogenous or endogenous ligands are poorly understood. Elucidation of factors involved in the activation of the receptor would assist not only in development of an optimal measure for risk assessment of levels of common environmental pollutants but also in providing novel targets for therapeutic interventions. Posttranslational modifications (PTMs) play an indispensable role in all major signal transduction pathways by increasing the inventory of chemical modifications beyond those already present in the side-chains of common amino acids. Thus, by simple on/off or complex patterns generated by these PTMs, they control a myriad of different biological outcomes. Numerous studies that have suggested an important role of posttranslational modifications in DR activation has prompted a search in this direction, however, apart from phosphorylations at Ser36 and Ser68 no other PTM sites are known. Advanced mass spectrometry (MS)-based characterisation of PTMs is an established technique that can comprehensively provide an accurate cast of all PTM variants and their locations on a protein. This thesis reports the first MS-based comprehensive characterisation of all PTM sites of the purified latent DR and preliminary analysis of identified PTM sites of the activated DR in response to developmental signals (suspension-activated DR) and signals leading to toxic outcomes (ligand-activated DR). The PTM map of the latent DR revealed from this study comprises of 25 phosphorylations, 4 monomethyl-lysines, 2 dimethyl-lysines, 1 O-acetyl-serine and 2 O-sulfono-serines. Most of the phosphorylations and other PTMs were present in the conserved regions of the protein. Investigation of the activated samples of the receptor revealed loss of the above repertoire of modifications and possible presence of some rarer modifications such as O-acetyl-serines in suspension-activated instead of O-sulfonations and pyrophosphorylation at Ser716 in both suspension- as well as ligand-activated DR. A comprehensive mutagenesis study is in progress to understand the functional consequence of each of these modification sites and unravel the functional posttranslational system in DR signalling.

The dioxin receptor (DR), a transcription factor with basic-helix-loop-helix/PERARNTSIM (bHLH/PAS) homology domains, is activated by toxic xenobiotic ligands leading to severe physiological disturbances most of which are due to deregulation of receptor’s central role in normal development. Activation mechanisms of DR in the presence of exogenous or endogenous ligands are poorly understood. Elucidation of factors involved in the activation of the receptor would assist not only in development of an optimal measure for risk assessment of levels of common environmental pollutants but also in providing novel targets for therapeutic interventions. Posttranslational modifications (PTMs) play an indispensable role in all major signal transduction pathways by increasing the inventory of chemical modifications beyond those already present in the side-chains of common amino acids. Thus, by simple on/off or complex patterns generated by these PTMs, they control a myriad of different biological outcomes. Numerous studies that have suggested an important role of posttranslational modifications in DR activation has prompted a search in this direction, however, apart from phosphorylations at Ser36 and Ser68 no other PTM sites are known. Advanced mass spectrometry (MS)-based characterisation of PTMs is an established technique that can comprehensively provide an accurate cast of all PTM variants and their locations on a protein. This thesis reports the first MS-based comprehensive characterisation of all PTM sites of the purified latent DR and preliminary analysis of identified PTM sites of the activated DR in response to developmental signals (suspension-activated DR) and signals leading to toxic outcomes (ligand-activated DR). The PTM map of the latent DR revealed from this study comprises of 25 phosphorylations, 4 monomethyl-lysines, 2 dimethyl-lysines, 1 O-acetyl-serine and 2 O-sulfono-serines. Most of the phosphorylations and other PTMs were present in the conserved regions of the protein. Investigation of the activated samples of the receptor revealed loss of the above repertoire of modifications and possible presence of some rarer modifications such as O-acetyl-serines in suspension-activated instead of O-sulfonations and pyrophosphorylation at Ser716 in both suspension- as well as ligand-activated DR. A comprehensive mutagenesis study is in progress to understand the functional consequence of each of these modification sites and unravel the functional posttranslational system in DR signalling.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-10-18T14:09:42Z No. of bitstreams: 3 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DissertaçãoParcial (Int+Rev.Bib.)_RayanneOliveira_PPGQ.pdf: 845718 bytes, checksum: 0a5d75959d08a34106f153820f6db704 (MD5) Reprodução Não Autorizada.pdf: 47716 bytes, checksum: 0353d988c60b584cfc9978721c498a11 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-10-18T14:09:55Z (GMT) No. of bitstreams: 3 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DissertaçãoParcial (Int+Rev.Bib.)_RayanneOliveira_PPGQ.pdf: 845718 bytes, checksum: 0a5d75959d08a34106f153820f6db704 (MD5) Reprodução Não Autorizada.pdf: 47716 bytes, checksum: 0353d988c60b584cfc9978721c498a11 (MD5) / Made available in DSpace on 2018-10-18T14:09:55Z (GMT). No. of bitstreams: 3 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DissertaçãoParcial (Int+Rev.Bib.)_RayanneOliveira_PPGQ.pdf: 845718 bytes, checksum: 0a5d75959d08a34106f153820f6db704 (MD5) Reprodução Não Autorizada.pdf: 47716 bytes, checksum: 0353d988c60b584cfc9978721c498a11 (MD5) Previous issue date: 2018-07-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Liquid inorganic acids are widely used as homogeneous catalysts in esterification reactions. Although highly active and low cost, it is imperative a tedious process for separation and purification of the final product. Besides the large volume of toxic and corrosive waste produced, there is also the drawback such as corrosion of equipment and difficulty for recycling the catalyst. Thereby, heterogeneous catalysis is a pathway to cleaner, safer and economically viable processes to produce chemicals for industry. Therefore, it is encouraged the production of heterogeneous catalysts must be at low cost and highly catalytic activity. Moreover, it is worldwide the use of biomass waste as raw materials for the production of heterogeneous catalysts. Herein, the acai stone (Euterpe oleracea Mart.), an amazon biomass waste from the processing of Acai fruits, was sulfonated and applied as a heterogeneous catalyst. By using esterification as model reaction we could check its catalytic active. The catalysts were synthesized at different carbonization temperatures, following the sulfonation by sulfuric acid at room temperature. The catalytic activity was tested in the reaction of oleic acid with methanol. For this reaction the experimental set was molar ratio of 1:12, 5% of catalyst, and reaction temperature of 100°C for 1h. The carbon material catalysts yielded 93% of methyl ester, while the reaction without catalyst showed 12% of methyl ester. In summary, this study shows promising results for obtaining carbon-based catalysts from the acai biomass waste and comes with the main novelty of preparing a sulfonic functionalized catalyst room temperature. / Ácidos inorgânicos são amplamente utilizados como catalisadores homogêneos em reações de esterificação. Embora sejam altamente ativos e não onerosos, é necessário um processo especial de separação e purificação do produto final, o que resulta no grande volume de resíduos tóxicos e corrosivos, além das desvantagens como a corrosão de equipamentos e dificuldade no reciclo do catalisador. Desse modo, a catálise heterogênea surge com a proposta de desenvolver processos mais limpos, mais seguros e economicamente viáveis para produzir ésteres. Dentro desse contexto, também é incentivado à produção de catalisadores heterogêneos de baixo custo e alta atividade catalítica. Já é comum o reaproveitamento de resíduos da biomassa como matéria-prima para produção de carbonos microporosos. Neste trabalho, o caroço de Açaí (Euterpe oleracea Mart.), um resíduo da biomassa Amazônica proveniente do processamento de frutos do Açaí, um fruto nativo da Amazônia brasileira, foi sulfonado e aplicado como catalisador heterogêneo na reação modelo de esterificação. Foram sintetizados catalisadores em diferentes temperaturas de carbonização. Após esta etapa o material foi submetido ao processo de sulfonação. A eficiência catalítica do material foi comprovada sob as condições de reação: razão molar ácido oleico/metanol 1:12, carregamento de catalisador 5%, temperatura de 100°C por 1h. Obteve-se uma conversão em ésteres metílicos de 93% com o uso do catalisador, enquanto que a reação sem catalisador apresentou apenas 12% de conversão. Esse estudo mostra resultados promissores para a obtenção de catalisadores heterogêneos sulfonados a partir da biomassa residual do caroço do Açaí e vem com a principal novidade de preparar um catalisador a partir da funcionalização com ácido sulfúrico à temperatura ambiente.

The sulfonation of toluene at -12.5° C. with sulfur trioxide in liquid sulfur dioxide was found to give 10.03 ± 0.20 % ortho, 0.73 ± 0.20 % meta and 89.24 ± 0.20 % para isomers. This isomer distribution was determined by isotope dilution analysis using sulfur-35 enriched sulfur trioxide. After dilution of aliquots of the neutralized sulfonation mixture with pure sodium salts of each of the isomers prepared from the corresponding toluidines, the isomers were converted to the p-toluidine salts, purified by recrystallization, and counted by liquid scintillation counting. The relative rate of sulfonation of toluene compared to benzene was studied under the same conditions. The analysis in this case was accomplished by ultraviolet spectrophotometry. The only assumption made was that the isomer distribution of toluene does not change when benzene is added during the sulfonation. The results show that the relative rate (kt/kb) is 10.9 ± 1,5 at low benzene to toluene ratios but increases considerably at high ratios. The hydrochlorination of cyclohexerte, cis-2-butene and trans-2-butene with stannic chloride catalyst was studied in n-heptane solvent. The kinetics were found to be considerably influenced by trace impurities, especially moisture. The kinetics were found to be first order in olefin and stannic chloride and from zero to three and one-half order in hydrogen chloride depending on the amount of moisture present. When moisture is absent, unexplained abnormal kinetics occurred. Polymerization, cyclization, alkylation, and dehydrochlorination were insignificant under the conditions of the kinetic experiments.

This dissertation describes the past and recent progress in proton exchange membranes (PEM) for fuel cells. In particular the synthesis and characterization of materials for advanced alternative PEM were studied with an emphasis on structure-property and structure-property-performance relationships. The focus has included firstly a one-step synthesis and characterization of 3,3'-disulfonated 4,4'-dichlorodiphenyl sulfone comonomer. The procedure developed is adaptable for industrial-scale commercialization efforts. Secondly, the synthesis of aromatic nitrile containing poly (arylene ether sulfone) random copolymers was demonstrated. Various levels of disulfonation allowed the membrane characteristics to be investigated as a function of the membrane ion exchange capacity. The results favorably compare with the current state-of-the-art (Nafion™), particularly for direct methanol systems (DMFC). Thirdly, the mechanically and thermooxidatively stable copolymer membranes were blended with heteropolyacids producing nanocomposites which have potential in higher temperature fuel cell applications. Lastly, the basic PEM parameters such as water uptake, proton conductivity, and methanol permeabilities were controlled and presented as tunable properties as a function of molecular structure. This was achieved by in-situ control of chemical composition. The direct methanol fuel cell performance (DMFC) was much better than Nafion™. Hydrophobic surface properties of the membranes were improved by partial fluorination which made the Nafion™ bonded electrodes more compatible with the partially fluorinated copolymer membranes. The influence of surface enrichment had two important roles in increasing both initial and long term performance tests. The surface fluorine provided lower contact resistance and lower water uptake. The former was important for the initial tests and the latter provides for better long term performances. A delamination failure mechanism was proposed for the hydrocarbon membrane electrode assemblies (MEA) due to the large difference between water uptake of the catalyst layer and membrane and this was verified by a reduction in high frequency resistance (HFR) for the partially fluorinated systems. This thesis has generated the structure-property and structure-property-performance relationships which will provide direction for the development of next generation (PEM) materials. / Ph. D.

Over 30% of the world's population does not have access to safe drinking water, and the need for clean water spans further than just for human consumption. Currently, we use freshwater for growing agriculture, raising livestock, generating power, sanitizing waste, mining resources, and fabricating consumer goods. With that being said, the world is beginning to feel pressure from the excessive freshwater withdrawal compared to the current freshwater supply. This water stress is causing a water crisis. Places including Australia, South Africa, and California in the United States, just to name a few, are beginning to run out of fresh water to support daily societal demands. This is a phenomenon that is indiscriminately observed in all ranges of economically and politically developed countries and environments. However, it is important to note that less politically and economically developed countries especially those in arid climates, experience higher water stress than countries without such qualities. With only 2.5% of the world's water being freshwater and 30% of it being accessible as either ground or surface water, freshwater is a scarce resource, especially with the growing population and society's demand for water. Since the remaining 97.5% of water is composed of either brackish or seawater (saline water sources), one way to overcome the water stress would be to convert saline water into freshwater. As a result, various desalination techniques have been developed in the last 80 years that employ either membrane technology or temperature alterations to desalinate either brackish or seawater. One of the fastest growing methods for producing freshwater is reverse osmosis. Reverse osmosis uses an externally applied pressure, in the form of a cross flow back pressure, to overcome the osmotic pressure produced by the saline gradient across a semi-permeable membrane. The semi permeable membrane commercially consists of an interfacially polymerized aromatic polyamide thin film composite with a polysulfone porous backing that allows water to pass through while barring the transport of salt ions. This research focuses on the development of sulfonated poly(arylene ether sulfone) derivatives with differing amounts of sulfonation and with the ions placed at different structural positions. Previously, such materials were tested as potential high performance fuel cell membranes, but they are also of interest as potential high performance water desalination membranes, specifically for reverse osmosis. Two different methods were used to synthesize the sulfonated polysulfone derivatives: direct polymerization and post-modification of a non-sulfonated active polysulfone. The polysulfones from direct polymerization incorporated specialty sulfonated monomers, which were stoichiometrically controlled during the polymerization. Sulfonated polysulfones that were synthesized from post sulfonation incorporated biphenol and hydroquinone monomer units randomly throughout the polysufone backbones. These units could be sulfonated selectively because of their activation towards electrophilic aromatic substitution with sulfuric acid. Each of the polymers were cast into films ranging between 20-100 microns in thickness and tested for water uptake, hydrated uniaxial tensile properties, crossflow water and salt transport properties, and for crosslinked samples, gel fractions. The water uptakes from all the polysulfones were tuned by the degree of sulfonation or disulfonation present in the polymer. This was either controlled via the presence of a sulfonated monomer or a monomer that was active toward electrophilic aromatic substitution after polycondensation of the polysulfone. All polymers exhibited increases in their water uptake as the degree of sulfonation increased. We also observed a decreasing trend in the hydrated mechanical properties of the films for all the high molecular weight linear polymers as the water uptake was increased. The directly polymerized sulfonated polysulfones were found to have high hydrated elastic moduli ranging between 400 and 1000 MPa, while the post sulfonated counterparts (with either hydroquinone or biphenol incorporated in their structures) exhibited elastic moduli ranging between 1000 and 1500 MPa. It is important to note that the structures of the polymers were slightly different from one another because of the technique used to synthesize them. Thus, the increases in hydrated moduli among polymers synthesized via different routes may have influences from differences in chemical structures. Some of the polymers with higher degrees of sulfonation were synthesized as amine terminated oligomers with varying controlled molecular weights. The two targeted molecular weights were 5 and 10 kDa. Those oligomers were then crosslinked with a tetra-functional epoxide agent. The increases in sulfonation allowed for increases in water uptake and in theory, the water throughput through the sulfonated polysulfone membrane. Decreases in hydrated mechanical performance of the crosslinked networks with increasing degrees of sulfonation were also observed, similar to their high molecular weight linear counterparts. The directly polymerized crosslinked networks had salt permeabilities that plateaued at 70% disulfonation for both the 5 and 10 kDa polymers. Thus, we expect disulfonation content greater than 70% would lead to higher water throughput without significant increases in salt transport. / Doctor of Philosophy / A worldwide shortage of freshwater is becoming more problematic by each passing day. The World Health Organization and the United Nation's World Water Assessment Program predict that by 2025, 50-66% of the world's population will be living in a water-stressed area. This includes any area that experiences higher clean water withdrawals than are available. This includes but is not limited to areas that are politically unstable, technologically disadvantaged, resource deficient, located in arid climates, and highly populated. To put this further into perspective, only 2.5% of the available water on earth is freshwater. Freshwater typically has low concentrations of dissolved salts that are safe for human consumption and use. Of the available freshwater, only 30% of it is actually accessible for use through either surface or groundwater reservoirs, making the amount of clean water available for usage already a scarce resource. On the other hand, 97.5% of the world's water is composed of saline water reservoirs in the form of brackish and seawater. Through harnessing, seawater and removing the excess dissolved salt ions, the salt water can be converted to freshwater. Two major methods have been developed to remove the dissolved ions from water through either membrane filtration or thermal phase changes. One of the fastest growing membrane filtration techniques used worldwide is reverse osmosis. Reverse osmosis refers to the use of applied pressure across a semipermeable membrane to desalinate saline water. The semipermeable membrane prevents the migration of salt ions through the membrane while allowing transport of water. This work has focused on developing new polymers that can increase the overall efficiency of water desalination. Different types of high performance sulfonated polysulfone derivative polymers were synthesized and used to make membranes that were subsequently tested for performance. Relationships between the polymer structure, process, and properties were quantified through different analytical techniques. This study showed how the properties of sulfonated polysulfone membranes may be manipulated depending on structural modifications and processing to increase both the material's water throughput and salt rejection.