Les batteries Li-ion sont désormais si omniprésentes dans notre société qu’il nous est difficile de concevoir un futur sans elles. Leur usage à grande échelle engendre toutefois plusieurs problèmes politiques, sociologiques, économiques et écologiques reliés à l’exploitation, la distribution et la disposition des matériaux requis incluant notamment le lithium et le cobalt. Les matériaux cathodiques en particulier sont souvent toxiques, dispendieux et difficiles à recycler et la performance des matériaux disponibles limite présentement la performance des batteries. Il est conséquemment plus que jamais nécessaire de développer de nouveaux matériaux cathodiques performants pour les batteries Li-ion et de s’intéresser au développement de nouvelles alternatives plus vertes. Les matériaux organiques électro-actifs sont prometteurs en tant qu’alternative aux matériaux d’électrode actuels puisqu’ils sont versatiles, potentiellement plus performants et peuvent être dérivés de ressources renouvelables. Les quinones en particulier soulèvent beaucoup d’intérêt pour la conception de cathodes organiques en raison de leurs processus rédox rapides, réversibles et multiélectroniques. L’état des connaissances reliées à leur intégration aux batteries demeure toutefois sous-développé par rapport à celui des composés d’intercalation inorganiques et plusieurs efforts sont encore nécessaires afin de mener au développement de batteries organiques performantes; plusieurs classes de matériaux organiques demeurent inexplorées et les principes structuraux menant à des matériaux performants sont encore à élucider. Dans cette optique, nous nous sommes intéressés à l’étude des diphénoquinones, une classe de composés quinoïdes disposant de potentiels plus élevés que les quinones communes et pouvant être préparées par le couplage oxydatif de substrats abondants et potentiellement dérivés de la biomasse. Les diphénoquinones sont très peu solubles et hautement cristallines, ce qui leur permet de produire des électrodes stables et performantes. Malgré cela, ces composés attrayants demeurent peu étudiés et leur intégration aux batteries est négligée. / Li-ion batteries have become so omnipresent in our society that it is difficult to envision a future without them. However, their large-scale production leads to numerous political, sociologic, economic and ecological problems related to the exploitation, distribution and disposition of materials required for their production, including notably lithium and cobalt. Cathodic materials in particular are often toxic, expensive and hard to recycle, and their efficiency is currently limiting the overall performance of batteries. Consequently, it is now more than ever necessary to create new efficient cathodic materials and to revisit the development of alternatives to Li-ion batteries. Organic electro-active materials represent a promising alternative to current battery electrode materials as they are versatile, potentially more efficient and can be derived from renewable resources. Quinones in particular stir a lot of interest which stems from their rapid and reversible multi-electronic redox processes. The state of knowledge related to their integration to batteries yet remains under-developped as opposed to that of inorganic intercalation compounds and many additional efforts are required to develop efficient organic batteries; many classes of organic materials remain unexplored and the structural principles leading to efficient organic electrodes have yet to be uncovered. In this context, we have revisited the study of diphenoquinones, a class of quinonoid compounds which exhibit higher redox potentials than common quinones and can be derived from the oxidative coupling of abundant organic substrates potentially derived from biomass. Diphenoquinones have very low solubility and show a high degree of crystallinity, which allows them to prepare stable and efficient electrodes. Despite this, these attractive compounds remain poorly studied and their integration to batteries has been neglected.

Made available in DSpace on 2017-07-20T12:40:14Z (GMT). No. of bitstreams: 1 Giselle Nathaly Calaca.pdf: 4129912 bytes, checksum: 17ad0dde0faa7762fe24c34e6ffcd471 (MD5) Previous issue date: 2015-03-23 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / The development and validation of analytical methods for quantification of two associations, antibiotics: sulfamethoxazole (SMX) and trimethoprim (TMP); and depigmenting agents: kojic acid (AK) and hydroquinone (HQ), using unmodified glassy carbon electrode (ECV) and square wave voltammetry (SWV) are described. For the first association, two well defined irreversible oxidation peaks were obtained at 0.96V (SMX) and 1.12V (TMP) in Britton–Robinson buffer (pH 6.0), characterized by diffusion and adsorptive processes, respectively. SWV parameters were optimized by means of 23 Full Factorial Design, and the best analytical signal, in terms of sensitivity and selectivity is obtained at a=30 mV, f=100 s-1 and ΔES=5mV. Under optimized conditions, SWV measurements showed excellent linear response, from 5.5x10-5 to 3.95x10-4 mol L-1 (R=0.9971) and 1.05x10-5 to 1.04x10-4 mol L-1 (R=0.9974) for SMX and TMP, respectively. The detection and quantification limits were found to be 8.52x10-6 mol L-1 and 2.84x10-5 mol L-1 for SMX; and 9.31x10-7 mol L-1 and 3.10x10-6 mol L-1 for TMP, respectively. The proposed method was successfully applied to the simultaneous determination of these antibiotics in commercial pharmaceutical formulations (tablets, oral suspension and injection), without any sample pretreatment. The obtained results are in good agreement with that obtained by the standard HPLC method at a 95% confidence level. For the second association, the redox peak potentials were completely separated in Mcllvaine buffer solution (pH 8.0), KA exhibits a well-defined irreversible oxidation peak at 0.72V and HQ a quasi-reversible redox peak at 0.08 V and -0.02 V, characterized by adsorptive and diffusional processes, respectively. Under SWV parameters optimized (a= 40 mV, f=40 s-1 and ΔES=1mV) by 23 Full Factorial Design, the calibration curves were obtained in the concentration ranges of 3.5×10-5 to 2.5×10-4 mol L-1 (R= 0.9996) for kojic acid and 1.5×10-5 to 1.6×10-4 mol L-1 (R= 0.9994) for hydroquinone. The detection and quantification limits were found to be 7.84x10-6 mol L-1 and 2.61x10-5 mol L-1 for KA; and 3.71x10-6 mol L-1 and 1.24x10-5 mol L-1 for HQ, respectively. The novel electroanalytical method was validated in terms of specificity, linearity, range, accuracy and precision (repeatability and intermediate precision) and successfully applied to the direct simultaneous determination of these bleaching agents in real samples. / O trabalho descreve o desenvolvimento e a validação de métodos analíticos para quantificação de duas associações, os antibióticos: sulfametoxazol (SMX) e trimetoprima (TMP); e os agentes despigmentantes: ácido kójico (AK) e hidroquinona (HQ), empregando-se eletrodo de carbono vítreo (ECV) não modificado e voltametria de onda quadrada (VOQ). Para a primeira associação, dois picos de oxidação irreversíveis em 0,96V (SMX) e 1,12V (TMP) foram observados em tampão Britton–Robinson (pH 6,0), caracterizados por processos difusional e adsortivo, respectivamente. Os parâmetros instrumentais da VOQ foram otimizados por meio de um planejamento fatorial completo 23, sendo a melhor resposta em termos de sensibilidade e seletividade obtida em a=30 mV, f=100 s-1 e ΔES=5mV. Nas condições otimizadas, foram construídas curvas analíticas nos intervalos de concentração de 5,5x10-5 a 3,95x10-4 mol L-1 (R=0,9971) para SMX e 1,05x10-5 a 1,04x10-4 mol L-1 (R=0,9974) para TMP. Os valores de limites de detecção (LD) e de quantificação (LQ) calculados foram: 8,52x10-6 mol L-1 e 2,84x10-5 mol L-1 para SMX e 9,31x10-7 mol L-1 e 3,10x10-6 mol L-1 para TMP, respectivamente. O método proposto foi aplicado para determinação simultânea dos fármacos em diferentes amostras farmacêuticas (comprimidos, injeção e suspensão oral) sem a necessidade de nenhum tipo de pré-tratamento da amostra. Os resultados obtidos através do método voltamétrico foram comparados aos obtidos pelo método farmacopeico (HPLC) e comprovou-se que não há diferença significativa em um nível de confiança de 95%. Para a segunda associação, nos voltamogramas cíclicos em tampão Mcllvaine (pH=8,0) um pico de oxidação irreversível em +0,7V foi observado para o AK, enquanto que para HQ foi observado um processo quase-reversível, com picos de oxidação em 0,08V e redução em -0,02V, caracterizados por processos adsortivo e difusional, respectivamente. Utilizando-se os parâmetros da VOQ otimizados (a= 40 mV, f= 40 s-1 e ΔES= 1mV), através de um planejamento fatorial completo 23, as curvas de calibração foram obtidas nas faixas de concentração de 3,5×10-5 a 2,5×10-4 mol L-1 (R= 0,9996) para AK e 1,5×10-5 a 1,6×10-4 mol L-1 (R= 0,9994) para HQ. Os limites de detecção e quantificação foram: 7,84x10-6 mol L-1 e 2,61x10-5 mol L-1 para AK; e 3,71x10-6 mol L-1 e 1,24x10-5 mol L-1 para HQ, respectivamente. O método voltamétrico desenvolvido foi validado em termos de especificidade, linearidade, faixa de concentração, exatidão e precisão (repetibilidade e precisão intermediária) e aplicado na determinação simultânea dos agentes despigmentantes em amostras de clareadores.

Inspired by natural catalytic systems, metalloporphyrins and Salen complexes have been used as catalysts for the oxidation of xenobiotics in the presence of several oxygen donors, both in homogeneous and heterogeneous catalysis. These catalysts have been highly efficient and selective in the reactions of different substrates, such as pharmaceuticals and pesticides. In this context, the work developed in this dissertation presents the oxidation studies of 2,4-dichlorophenoxyacetic acid herbicide using ferroporphyrins and Jacobsen catalyst as catalysts of these reactions with several oxygen donors. The results shows that the metalloporphyrin and the complex employed in this study are efficient catalysts for oxidation of 2,4-D in the presence of oxygen donors iodosilbenzene (PhIO), metachloroperbenzoic acid (m-CPBA) and hydrogen peroxide (H2O2) both in homogeneous and heterogeneous. The reactions with the unsupported catalysts achieved higher yields than those obtained with the supported catalysts, which is possibly related to the difficulties of access to the catalytic center imposed by the support. The conversion of 2,4-D reached more than 50% in some systems, and, in general, oxidation reactions with the three oxygen donors were selective promoting the formation of hydroquinone (reactions with PhIO and H2O2) and 3,5- dichlorocatechol (reactions with m-CPBA). One of the products identified in the reactions is a metabolite of 2,4-D produced in vivo systems, indicating that the catalysts used in this study can be considered good models of cytochrome P450 in the oxidation of 2,4-D. / Inspirados em sistemas catalíticos naturais, metaloporfirinas e complexos salen têm sido utilizados como catalisadores para a oxidação de xenobióticos na presença de diversos doadores de oxigênio, tanto em catálise homogênea quanto heterogênea. Esses catalisadores têm se mostrado altamente eficientes e seletivos nas reações de diferentes substratos, tais como fármacos e pesticidas. Dentro desse contexto, o trabalho desenvolvido nessa dissertação apresenta os estudos da oxidação do herbicida ácido 2,4-diclorofenoxiacético (2,4-D) utilizando ferroporfirinas e catalisador de Jacobsen como catalisadores dessas reações com diversos doadores de oxigênio. Os resultados mostram que a metaloporfirina e o complexo salen empregados nesse estudo são eficientes catalisadores para a oxidação do 2,4-D na presença dos doadores de oxigênio iodosilbenzeno (PhIO), ácido metacloroperbenzóico (m-CPBA) e peróxido de hidrogênio (H2O2), tanto em meio homogêneo como heterogêneo. As reações com os catalisadores não suportados alcançaram rendimentos mais altos do que os obtidos com os catalisadores suportados, o que está possivelmente relacionado as dificuldades de acesso ao centro catalítico imposta pelo suporte. A conversão de 2,4-D atingiu mais de 50% em alguns sistemas, e, em geral, as reações de oxidação com os três doadores de oxigênio foram seletivas promovendo a formação de hidroquinona (reações com PhIO e H2O2) e 3,5-diclorocatecol (reações com m-CPBA). Um dos produtos identificados nas reações é um metabólito do 2,4-D produzido sistemas in vivo, indicando que os catalisadores utilizados nesse estudo podem ser considerados bons modelos do citocromo P450 na oxidação do 2,4-D.