The overall goal of this research is to synthesize two different monomers for proton exchange membrane (PEM) Fuel Cells. Such monomers are proposed to be polymerized to improve the efficiency and compatibility of electrodes and electrolytes in PEM fuel cells. The first target is to synthesize 4-diazonium-3-fluoro PFSI zwitterionic monomer. Three steps were carried out in the lab. First one was the ammonolysis of 3-fluoro-4-nitrobenzenesulfonyl chloride. Second reaction was the bromination of Nafion monomer. The next coupling reaction, between brominated Nafion monomer and the 3-fluoro-4-nitrobenzenesulfonamide, was failed. The obstacles involve the harsh reaction condition and troublesome purification procedure. The second target is to synthesize 5-nitro-1, 3-benzenedisulfonamide. According to the literature, this synthesis was also designed as three steps: 1)nitration of sodium 1, 3-benzenedisulfonate salt; 2)chlorination of sodium 5-nitro-1, 3-benzenedisulfonate salt; and 3)ammonolysis of 5- nitro-1, 3- benzenedisulfonyl chloride. This monomer is expected to be copolymerized for membrane electrolyte in PEM fuel cells.

This thesis summarizes the outcome of work performed withthe objective to contribute to the knowledge and development ofthe kraft cooking process using spectrophotometricinterfaces. In kraft cooking, it is desirable to maximize the removal oflignin in the cook without loss of pulp strength. Theselectivity can be improved by exchanging some of the hydrogensulfide ion in the white liquor for polysulfides. Paper Ipresents a spectrophotometric method for in-line monitoring ofthe electrochemical production of polysulfide using anATR-probe for the UV-Vis range. A linear relation existsbetween the ATR-probe response and the concentration ofabsorbing species. Thus the process can be followed by simplemonitoring of a few wavelengths. A spectrophotometric monitoring system using a durableNafion ionomer membrane interface for continuous on-linemeasurement of sulfide and dissolved lignin during kraftcooking has previously been developed by our group. In paperII, the permeation of low molecular weight anions from liquorshaving high ionic strengths through a membrane in Na+ form hasbeen studied. A general relation between penetration and ionsize approximated by molecular weight has been established. Thepenetration of different anions can be explained as a diffusionthrough the winding membrane channels. Further the differentanions transport independently without being interfered by thesample matrix. In light of this validation, we applied the membraneinterface to the determination of anthraquinone-2-sulfonate(AQ-S) in alkaline pulping liquor. In paper III, a simple andrapid spectrophotometric method was developed and implementedon real samples. Interferences from other compounds penetratingthe membrane were minimized by reduction of the penetrated AQ-Sand measurement at 520 nm. This method is quick and can be usedon-line. Further, we extended the method to determination ofanthraquinone (AQ) in pulping liquor (paper IV). Although AQ isregarded as insoluble, it was found that the apparentsolubility of AQ in alkaline solutions increases considerablyin the presence of lignin, reaching 0.14 g/L at 90 oC. Thismakes the calibration of AQ possible. Time-resolvedmeasurements of dissolved AQ in 3 kraft-AQ pulping processeswere performed. The results show that the membrane has great potential aspart of a selective interface in applications where theconcentrations of small anions are to be monitored in mediawith high ionic strength. Keywords: Kraft cooking, On-line, Sulfide, Lignin,Polysulfide excess sulfur, Anthraquinone-2-Sulfonate (AQ-S),Anthraquinone (AQ), Nafion Membrane, UV-Vis, ATR-probe,Spectrophotometric.

Ce travail a tout d'abord porté sur la réactivité des dérivés borés puis sur la réaction de O-alkylation des alcools aromatiques. L'utilisation des composés borés est en plein essor. Ils sont employés comme partenaires de couplage dans la réaction de Suzuki et les réactions d'additions [1,4] catalysées au rhodium pour la synthèse de molécules à hautes valeurs ajoutées. La polarisation de la liaison C-B induit le caractère nucléophile de ces composés. Cette réactivité a été exploitée pour la formation de liaisons C-F par fluoration électrophile. L'utilisation de Selectfluor® comme agent de fluoration aboutit à de bons rendements. Toutefois, la nucléophilie des composés alkylborés peut être inversée par substitution nucléophile oxydante. Ainsi, une méthode créant des liaisons C-N a pu être développée et a permis la synthèse d'amides à partir de nitriles et de sels de trifluoroborates de potassium en présence de Cu(OAc)2 et BF3.OEt2. En vue de l'importance de la chimie des éthers en synthèse organique, une méthode de préparation d'éthers aryliques a été développée au laboratoire. En partant d'un système stœchiométrique en trifluorure de bore, un système catalytique impliquant du triflate de cérium a été mis au point. Afin de répondre au mieux au concept de la chimie verte, un système catalytique hétérogène, sans solvant, a été décrit. Dans ce cas, le catalyseur employé est le Nafion® NR50, facilement recyclable, sans perte d'activité, et conduisant à de bons rendements avec les alcools aliphatiques et aromatiques. Des amines aromatiques secondaires peuvent également être préparées par cette méthode

<p>This thesis summarizes the outcome of work performed withthe objective to contribute to the knowledge and development ofthe kraft cooking process using spectrophotometricinterfaces.</p><p>In kraft cooking, it is desirable to maximize the removal oflignin in the cook without loss of pulp strength. Theselectivity can be improved by exchanging some of the hydrogensulfide ion in the white liquor for polysulfides. Paper Ipresents a spectrophotometric method for in-line monitoring ofthe electrochemical production of polysulfide using anATR-probe for the UV-Vis range. A linear relation existsbetween the ATR-probe response and the concentration ofabsorbing species. Thus the process can be followed by simplemonitoring of a few wavelengths.</p><p>A spectrophotometric monitoring system using a durableNafion ionomer membrane interface for continuous on-linemeasurement of sulfide and dissolved lignin during kraftcooking has previously been developed by our group. In paperII, the permeation of low molecular weight anions from liquorshaving high ionic strengths through a membrane in Na+ form hasbeen studied. A general relation between penetration and ionsize approximated by molecular weight has been established. Thepenetration of different anions can be explained as a diffusionthrough the winding membrane channels. Further the differentanions transport independently without being interfered by thesample matrix.</p><p>In light of this validation, we applied the membraneinterface to the determination of anthraquinone-2-sulfonate(AQ-S) in alkaline pulping liquor. In paper III, a simple andrapid spectrophotometric method was developed and implementedon real samples. Interferences from other compounds penetratingthe membrane were minimized by reduction of the penetrated AQ-Sand measurement at 520 nm. This method is quick and can be usedon-line. Further, we extended the method to determination ofanthraquinone (AQ) in pulping liquor (paper IV). Although AQ isregarded as insoluble, it was found that the apparentsolubility of AQ in alkaline solutions increases considerablyin the presence of lignin, reaching 0.14 g/L at 90 oC. Thismakes the calibration of AQ possible. Time-resolvedmeasurements of dissolved AQ in 3 kraft-AQ pulping processeswere performed.</p><p>The results show that the membrane has great potential aspart of a selective interface in applications where theconcentrations of small anions are to be monitored in mediawith high ionic strength.</p><p>Keywords: Kraft cooking, On-line, Sulfide, Lignin,Polysulfide excess sulfur, Anthraquinone-2-Sulfonate (AQ-S),Anthraquinone (AQ), Nafion Membrane, UV-Vis, ATR-probe,Spectrophotometric.</p>

Ce travail de thèse a pour but l'étude des effets de la contamination cationique sur la membrane électrolyte afin d'élaborer des outils de caractérisation et de diagnostic de cette pollution. Premièrement, la caractérisation physico-chimique de membranes PFSA commerciales a révélé des paramètres pertinents de structure et de propriété, qui ont été étudiés en fonction de leur dépendance à la capacité d'échange ionique (IEC).Deuxièmement, les propriétés thermiques des membranes contaminées par des cations ont révélé des changements dépendant fortement de l'acidité de Lewis du cation (LAS). Cette tendance a été corrélée à la nature de l'interaction des différents cations avec les groupements polaires de la chaîne polymère, révélée par FTIR. Enfin, l'influence du taux de pollution sur les différents paramètres thermiques et structuraux nous a permis de révéler ceux qui sont pertinents non seulement à l'identification mais aussi à la quantification de la pollution. Une application des courbes d'étalonnage a été réalisée sur des membranes vieillies issues de systèmes réels après fonctionnement.

Le Nafion dans la couche catalytique des PEMFCs peut former un revêtement de film ultra-mince enrobant la surface du catalyseur et ses supports. La morphologie du Nafion se révèle être très sensibles à la nature du matériau sur lequel le film est déposé, et en particulier le caractère hydrophobe/phile de ces matériaux. Notre travail consiste à effectuer une enquête complète sur les effets hydrophiles du substrat sur les propriétés physiques du film ultra-mince de Nafion à des niveaux différents d'hydratation. Par conséquent, nous étudions selon un cadre unique une variété d'environnements spécifiques de la couche du catalyseur de la PEMFC, pouvant aller d'un substrat hydrophobe (carbone) à hydrophile (platine). La méthode numérique choisie pour ce travail est une simulation par Dynamique Moléculaire classique. Les configurations de films ultra-minces correctement thermalisés ont été décrites en détail en fonction de leurs propriétés structurales et dynamiques. / Nafion inside Polymer Electrolyte Membrane Fuel Cells (PEMFC) catalyst layers can be found as an ultra-thin film coating the catalyst and the catalyst support surfaces. Nafion morphology shows to be strongly sensitive to the type of material where the film is deposited, especially the hydrophobic/philic character of these materials. Our work consists in performing a complete investigation of the substrate hydrophilicity effects on the physical properties of Nafion ultra-thin film at different hydration levels. We investigate in a unique framework a variety of environments peculiar of the PEMFC catalyst layer, ranging from hydrophobic (carbon) to hydrophilic (platinum) substrates. The numerical method chosen for this work is classical Molecular Dynamics simulations. The well-thermalized thin-film configurations were described in details in terms of their structural and dynamical properties.

Made available in DSpace on 2014-06-12T15:52:53Z (GMT). No. of bitstreams: 2 arquivo5104_1.pdf: 1283154 bytes, checksum: cd06c2888a7832eb86607c735861d531 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2004 / Uma preparação contendo as isoformas 1 e 4 da lectina de sementes de Cratylia mollis (Cramoll 1,4) e uma lectina de folhas de Bauhinia monandra (BmoLL) foram previamente purificadas por fracionamento com sulfato de amônio seguidos por cromatografia de afinidade em Sephadex G-75 e gel de guar, respectivamente. Cramoll 1,4 foi imobilizada em Sepharose CL-4B ativada com CNBr (Cramoll 1,4-Sepharose) e usada para purificar imunoglobulina A secretória (IgAS) de diferentes secreções humanas. Dacron ferromagnético na forma hidrazida (FDH) foi utilizado como suporte sólido para imobilizar Cramoll 1,4 (Cramoll 1,4-Dacron) e BmoLL (BmoLL-Dacron). As lectinas imobilizadas foram usadas para a purificação de glicoproteínas do colostro humano. Cramoll 1,4 foi adsorvida a contas de Nafion e caracterizada por voltametria cíclica., Cramoll 1,4-Dacron BmoLL-Dacron e Cramoll 1,4-Sepharose mostraram picos após a eluição bioespecífica. Os materiais eluidos da coluna de Cramoll 1,4 Sepharose foram submetidos a imunodifusão radial simples (SRID) contra Anti-IgA humana. Para a avaliação por voltametria cíclica da interação de Cramoll 1,4 com seu carboidrato específico, a lectina foi adsorvida a contas de Nafion e a resposta eletroquímica foi obtida usando um sistema de três eletrodos. Uma curva de calibração avaliou a concentração de glicose. Os picos eluídos mostraram bandas com migrações eletroforéticas similares às da IgAS do colostro humano em SDS-PAGE: cadeias pesada (H) e leve (L) bem como componente secretor. Os picos eluídos da coluna de Cramoll 1,4-Sepharose mostraram anéis de precipitação contra anti-IgA humana. A interação entre Cramoll 1,4 e diferentes concentrações de glicose mostraram picos de redução e oxidação. Esses picos anódicos e catódicos diminuíram com o aumento da concentração de glicose. Neste estudo IgAS foi purificada de diferentes secreções humanas em colunas contendo Cramoll 1,4 Sepharose, utilizando metil-a-D-manopiranosídeo glicose como eluente. Cramoll 1,4 e BmoLL e foram capazes de ligarem-se a FDH, podendo ser usadas como matrizes de afinidade para a purificação de glicoproteínas do colostro humano. O resultado da transferência de elétrons da Cramoll 1,4 durante a interação com a glicose foi significativo. O sistema pode ser usado como um sensor de calibração para determinar glicose

Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-04-07T17:50:24Z No. of bitstreams: 2 Dissertação - Kelly Rejane de Oliveira Araújo - 2017.pdf: 2397939 bytes, checksum: 0dbd2a7c4b642d80fbadf119bba1a9db (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-04-10T11:23:50Z (GMT) No. of bitstreams: 2 Dissertação - Kelly Rejane de Oliveira Araújo - 2017.pdf: 2397939 bytes, checksum: 0dbd2a7c4b642d80fbadf119bba1a9db (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-04-10T11:23:50Z (GMT). No. of bitstreams: 2 Dissertação - Kelly Rejane de Oliveira Araújo - 2017.pdf: 2397939 bytes, checksum: 0dbd2a7c4b642d80fbadf119bba1a9db (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / This work was developed with the objective of determining the oxidation profile of ascorbic acid in solution using cyclic voltammetry, square wave voltammetry and differential pulse voltammetry, observing the oxidation behavior due to the increase in the concentration of ascorbic acid in solution using In the electrochemical measurements, a carbon-modified glass-carbon electrode and Nafion®, a polymer widely used in electrochemical analysis. The experiments had an emphasy on standard ascorbic acid analysis, but were also performed with vitamin C tablets of different trade marks, obtaining in both a significant increase of the anodic peak currents coming from the oxidation of the ascorbic acid, resulting from a good stability Of the modified working electrode. For comparison purposes with the Nafion®-modified glass carbon electrode, standard ascorbic acid analyzes were also performed with the use of the vitreous carbon electrode. With the results of the analysis it was possible to determine the mass of ascorbic acid found in vitamin C tablets, from the construction of an analytical curve, in which it presented the necessary parameters for this. By varying the scanning velocities of the analyzes by cyclic voltammetry, it was possible to find out when plotting the current x square root velocity graphs by which process the oxidation of ascorbic acid on the electrode surface would occur. The electrochemical experiments with standard ascorbic acid showed the oxidation behavior by varying the pH of the phosphate buffer solution, evidencing the best pH range to work using the Nafion® modified glass carbon electrode. The use of square wave and differential pulse voltammetry techniques allowed to now the profile of the oxidation of ascorbic acid in vitamin C tablets, demonstrating a better sensibility in the peak current signal by the use of differential pulse voltammetry. / Esse trabalho foi desenvolvido com o objetivo de determinar o perfil da oxidação do ácido ascórbico em solução empregando a voltametria cíclica, a voltametria de onda quadrada e a voltametria de pulso diferencial, observando o comportamento da oxidação decorrente do aumento da concentração de ácido ascórbico em solução, usando nas medidas eletroquímicas um eletrodo de carbono vítreo modificado com uma mistura de carbono e Nafion®, um polímero largamente empregado em análises eletroquímicas. Os experimentos tiveram ênfase na análise de ácido ascórbico padrão, mas também foram realizados com comprimidos de vitamina C de marcas comerciais diferentes, obtendo, em ambos, um aumento significativo das correntes de pico anódica provenientes da oxidação do ácido ascórbico, resultante de uma boa estabilidade do eletrodo de trabalho modificado. Para avaliação do eletrodo de carbono vítreo modificado com Nafion® também foram realizadas análises de ácido ascórbico padrão com o uso do eletrodo convencional. Com os resultados das análises foi possível determinar a massa de ácido ascórbico encontrada nos comprimidos de vitamina C, a partir da construção de uma curva analítica, na qual apresentou os parâmetros necessários para tal. Variando as velocidades de varredura das análises, por voltametria cíclica, foi possível descobrir ao plotar os gráficos de corrente versus raiz quadrada da velocidade por qual processo ocorreria a oxidação do ácido ascórbico na superfície do eletrodo. Os experimentos eletroquímicos com ácido ascórbico padrão mostraram o comportamento da oxidação ao variar o pH da solução tampão fosfato, evidenciando a melhor faixa de pH para se trabalhar usando o eletrodo de carbono vítreo modificado com Nafion®. O uso das técnicas de voltametria de onda quadrada e de pulso diferencial possibilitou conhecer o perfil da oxidação do ácido ascórbico nos comprimidos de vitamina C, demonstrando melhor sensibilidade no sinal da corrente de pico pelo uso da voltametria de onda quadrada.

No description available.

The objectives of this research were to study the gas transport properties of proton exchange membranes (PEM), namely disulfonated poly(arylene ether sulfone) (BPSH-35), post sulfonated diels-alder poly(phenylene) (SDAPP), and poly(perfluoro sulfonic acid) (Nafion). The O2 gas permeabilities were found to be lower in BPSH and SDAPP as compared to poly(perfluoro sulfonic acid) because of difference in Tg (TgBSPH= 250 oC, TgSDAPP= 330 oC versus TgNafion=150 oC). Higher Tg polymers have a more rigid, inflexible polymer segments causing a reduction in gas permeability. In comparison to SDAPP, BPSH has a lower O2 gas permeability because of the bulky side groups in the SDAPP backbone. O2 sorption measurements were carried out both under non-humidified and humidified conditions as a function of relative humidity and temperature at a normal PEM operating pressure of 1 atm. Under non-humidified conditions, BPSH, SDAPP, and Nafion 112 exhibited Henry's Law sorption, consistent with dilute dissolution of O2 into the polymer matrix. The enthalpies of sorption were calculated to determine the interaction of O2 with each membrane. The sorption enthalpies in BPSH and SDAPP increased with increasing pressure indicating the formation of more O2-O2 interactions. The enthalpies in Nafion 112 were relatively constant with increasing pressure. In the presence of moisture, the sorption behavior changed from Henry's Law to Type IV sorption behavior, which is common in hydrophilic polymers. The SDAPP membrane was found to have the highest percent wet O2 mass uptake because of a higher number of sulfonic acid groups interacting with the water/O2 system. Finally the O2 sorption for various porous catalyst powders, consisting of platinum supported on carbon was measured in the non-humidified and humidified state. The catalysts were found to have Knudsen diffusion in the non-humidified state with 20 wt% Pt-C having the largest O2 sorption. In the humidified state, the highest O2 mass uptake was achieved with 40 wt% Pt-C. These results are explained in terms of the trade-off between catalyst dispersion and catalyst size. Furthermore, O2 sorption measurements were utilized for membrane electrode assemblies containing 40 wt% Pt-C and hot pressed at 210 oC for BPSH-35 (25 and 80K) and Nafion 112 membranes. The same sorption behavior occurred in the MEAs as in the neat membrane, but at a lower capacity. This is because the electrode introduces a more tortuous path to the gas molecules permeating across the membrane. / Ph. D.