Wastewater treatment has always been a problem to human settlers. Events such as the great stink of London during the summer of 1858 have pushed engineers into developing new technologies to deal with such wastes in effective and safe ways. Research projects like this aim to find ways of improving performance, economics, or environmental friendliness of treatment and disinfection methods. This thesis deals with the effectiveness, mechanisms of action, by-products and side effects of using DC current to disinfect secondary effluent. It is proposed as an alternative to conventional methods, such as chlorination, which are not always environmentally friendly or feasible. It was demonstrated that DC current efficiently kills pathogens. DC properly used achieves disinfection significantly higher than the minimum required by the EPA. Nevertheless disinfection by products such as residual chlorine should be taken into account when considering this technology as an alternative to conventional chlorination.

The pyrrolidine and piperidine ring systems are present in a variety of different classes of amphibian alkaloids. We have found the iridium catalyzed N-heterocylization reaction of diols with amines to be very useful for the construction of novel pyrrolidine, piperidine and piperazine derivatives. The scope and utility of the iridium catalyzed N-heterocyclization reaction for the construction of novel anuran scaffolds using amino diols and triols are presented. Studies directed towards the total synthesis of 4,6-disubstituted quinolizidine and (±)-epiquinamide are discussed. The second study is focused on the selective conversion of terminal dienes to primary diols. This conversion has always had problems with regioselectivity and low yields due to polymer formation with carbon chains having more than 7 carbon atoms. An improvement in the yield and regioselectivity was observed with disiamylborane prepared in situ using 2-methyl-2-butene and BH3•DMS. The scope of this method with 7, 8 and 9 carbon chains and different alcohol protecting groups for synthesis of triols is presented.

No description available.

Dans ce travail de thèse, plusieurs groupes de nouveaux complexes d'or(I) à base de carbènes N-hétérocyclique (NHC)contenant des bras amino-aliphatiques et aromatiques avec un potentiel intéressant dans des applications biomédicales ont été synthétisés et entièrement caractérisés. En outre, une série de complexes d'iridium(III) contenant des ligands NHC avec des activités anticancéreuses prononcées pour une application en thérapie photodynamique, a étépréparée et entièrement caractérisée. Le premier groupe représente une famille de complexes cationiques or(I) bis(NHC) contenant des bras latéraux amino-aliphatiques. Ces complexes ont étésynthétisés et étudiés pour leurs activités antiprolifératives vis-à-vis de quatre lignées cellulaires cancéreuses humaines et de la lignée cellulaire non cancéreuse MDCK. Dans cette série, la lipophilie est directement liée àl'activitécytotoxique contre les cellules cancéreuses. La deuxième famille de composés concerne les complexes cationiques or(I) bis(NHC) contenant des bras latéraux amino-aromatiques. La cytotoxicitéin vitro de ces complexes et de leurs proligands sur les lignées cellulaires représentatives du cancer de la prostate PC-3 et de la vessie T24 a étéévaluée. Tous ces complexes présentent des valeurs de Log P (lipophilie) supérieures àcelles de la première série de complexes en accord avec leur cytotoxicité plus élevée, mais une lipophilie trop élevée peut également conduire àune sélectivitéplus faible. Afin de développer un candidat-médicament avec une activitéet une sélectivité optimisées, nous avons conçu et synthétisé la troisième famille de complexes cationiques or(I) bis(NHC). Les valeurs de log P de cette série se situent entre la première série et la deuxième série. Ces complexes moins lipophiles sont moins cytotoxiques envers les lignées cellulaires saines (NIH3T3) et montre des activités anticancéreuses un peu plus faibles sur les cellules PC-3 que la deuxième série, avec néanmoins des valeurs de GI50 dans la gamme du nanomolaire. Les études mécanistiques sur deux complexes d'or(I) ont été réalisées. Les mesures d'absorption cellulaire ont montré une accumulation cellulaire rapide et une bonne biodisponibilitédes complexes, en accord avec l'activitéantiproliférative de ces deux complexes. De plus, les deux complexes inhibent la thiorédoxine reductase (TrxR), une cible commune pour les complexes d'or(I). La mort cellulaire induite par ces deux complexes est dépendante des espèces réactives de l'oxygène. En plus des activités anticancéreuses, nous avons également testédes complexes d'or(I) mono-NHC pour une autre application biomédicale, la leishmaniose, maladie parsitaire. Ils ont été testés in vitro sur les formes promastigotes et amastigotes axéniques de L. infantum. De plus, leur cytotoxicitéa étéévaluée sur les macrophages murins J774A.1 afin de déterminer leur sélectivitéd'action. Un autre sujet de cette thèse concerne les complexes d'iridium(III)-NHC. Trois familles de complexes ont étépréparées et caractérisées. La cytotoxicitéin vitro de tous les complexes sur les cellules cancéreuses de la prostate PC-3 et de la vessie T24, et les cellules non cancéreuses NIH3T3 a étéévaluée. De plus, tous les complexes sont des agents théranostiques, et les expériences de microscopie confocale d'un complexe ont montréqu'il pouvait être rapidement et efficacement absorbédans les cellules PC-3 et se localiser spécifiquement dans les mitochondries. De manière intéressante, ces complexes peuvent agir comme des photosensibilisateurs efficaces. La cytotoxicitéde ces complexes a étéaugmentée substantiellement après une irradiation lumineuse de 365 nm, ce qui suggère le potentiel élevéde ces agents anticancéreux théranostiques ciblant les mitochondries pour la thérapie photodynamique. / In this work of thesis, several groups of novel NHC-based gold(I) complexes containing aliphatic and aromatic amino-side arms with interesting potential in biomedical applications have been synthesized and fully characterized. Also, a series of iridium(III) complexes containing NHC ligands with pronounced PDT anticancer activities has been prepared and fully characterized. The first group represents a family of cationic bis(NHC)-gold(I) complexes containing aliphatic amino-side arms. These complexes have been synthesized and investigated for their antiproliferative activities towards four human cancer cell lines and the non-cancerous MDCK cell line. In this series, the lipophilicity correlates directly with the cytotoxic activity against cancer cells. The second family of compounds concerns cationic gold(I) bis(NHC) complexes containing aromatic amino-side arms. The in vitro cytotoxicity of these complexes and proligands on the representative PC-3 prostate and T24 bladder cancer cell lines has been evaluated. All these complexes show higher Log P values (lipophilicity) than the first series of complexes, and in line with this higher cytotoxicity, nevertheless too high lipophilicity can also lead to lower selectivity. In order to develop a drug candidate with optimized activity and selectivity, we designed and synthesized the third family of cationic gold(I) bis(NHC) complexes. The Log P values of this series were between the first series and the second series. The lower cytotoxicity towards non-cancerous NIH3T3 cells was found for this series of complexes whereas they also displayed less activities towards cancer cells than the second series. The mechanistic studies on two gold complexes by monitoring the cellular uptake showed the rapid cellular accumulation of the intact gold bis(NHC) and a good bioavailability, in good agreement with the antiproliferative activity of these two complexes. Moreover, both complexes inhibit TrxR, a common target for gold(I) complexes. The cell death induced by these two complexes was ROS-dependent. Besides anticancer activities, we also tested gold(I) mono-NHC complexes for other biomedical applications in parasite disease Leishmaniasis. They were screened in vitro against both promastigote and axenic amastigote forms of L. infantum. Moreover, their cytotoxicity was evaluated on the murine J774A.1 macrophages in order to determine their selectivity of action. Another topic of this thesis concerns iridium(III)-NHC complexes. Three families of theranostic iridium(III)-NHC complexes were prepared and characterized. The in vitro cytotoxicity of all the complexes against PC-3 prostate, T24 bladder cancer cells and non-cancerous NIH3T3 cells was evaluated. Moreover, all complexes are theranostic agents, and the confocal microscopy experiments of one complex showed that it can be quickly and effectively taken up into PC-3 cells and specifically localize into mitochondria. Interestingly, these complexes can act as efficient photosensitizers. The cytotoxicity of these complexes was increased substantially upon 365 nm light irradiation, which suggested the high potential to be mitochondria-targeting theranostic anticancer agents for photodynamic therapy.

INTRODUÇÃO: Braquiterapia de alta taxa de dose (BATD) para o câncer de próstata pode ser uma boa opção para escalonamento de dose, como um reforço de dose, associada à radioterapia externa, principalmente se não há disponibilidade de radioterapia tridimensional conformada ou tecnologia mais avançada. OBJETIVOS: Neste trabalho, analisaram-se os resultados e as toxicidades de um reforço de dose com BATD prévio à radioterapia externa convencional ou tridimensional conformada em pacientes portadores de câncer localizado da próstata. Fatores prognósticos relacionados à sobrevida livre de doença, além de toxicidade do tratamento também foram estudados. MÉTODOS: Estudo retrospectivo de 403 pacientes com adenocarcinoma localizado da próstata tratados entre dezembro de 2000 e março de 2004, que receberam 3 esquemas de fracionamento distintos de BATD de acordo com o seu grupo de risco: três frações de 5,5 a 6 Gy, 6 a 6,5 Gy ou 6,5 a 7 Gy, para baixo, médio ou alto risco, respectivamente, em um único implante, no decorrer de 24h de internação. A radioterapia externa convencional ou conformada compreendeu dose de 45 Gy na próstata e vesículas seminais. Foram realizadas análises uni e multivariada para avaliação dos fatores prognósticos relacionados à sobrevida livre de falha bioquímica e toxicidades. RESULTADOS: A idade mediana dos pacientes foi de 68 anos, com PSA médio de 9g/ml, peso prostático médio de 35 cc. Grau histológico de Gleason igual a 6 ocorreu em 43% dos casos, estádio menor do que T2c em 97%, presença de nódulo prostático em 49%; 11% dos pacientes apresentaram história de ressecção transuretral e 16% obstrução urinária prévias. No grupo de baixo risco foram classificados 36.1% dos pacientes, 42.8% no grupo de risco intermediário e 21.1% foram considerados de alto risco. Hormonioterapia neoadjuvante por até 6 meses foi utilizada em 64% dos casos e teleterapia conformada em 19%. O seguimento médio foi de 50 meses (mediano de 48,4 meses), variando de 24 a 113 meses. Nove (2,2%) pacientes não responderam ao tratamento e 4,5% evoluíram a óbito por neoplasia prostática em um tempo médio de 22 meses. Falha bioquímica, tanto pelo critério ASTRO, quanto PHOENIX ocorreu em 9,6% dos pacientes. Entretanto, o tempo médio para falha foi de 13 meses pelo critério ASTRO e 26 meses pelo PHOENIX. O único fator preditivo de falha bioquímica pela análise multivariada por ambos os critérios ASTRO e PHOENIX foi a presença de nódulos prostáticos, mas pacientes com menos de 60 anos apresentaram maior chance de falha apenas pela definição de PHOENIX. Toxicidades urinárias agudas como retenção e hematúria ocorreram em 2,8% e 1,3% dos casos, respectivamente; sendo 23,7% grau 1, 15,1% grau 2 e 2% grau 3. Estenose uretral tardia foi observada em 8,5% dos pacientes e as toxicidades urinárias tardias foram grau 1 em 8,8%, grau 2 em 3,9%, grau 3, em 7,7% e grau 4, em 0,3% dos casos. Toxicidade urinária aguda foi relacionada a obstrução urinária prévia e maior dose de braquiterapia na uretra. Estenose uretral tardia também foi relacionada à maior dose uretral pela braquiterapia e com maior idade. Toxicidade retal precoce ocorreu como grau 1 em 14,8% dos pacientes; como grau 2, em 10,5%; e como grau 3, em 1,3%. Toxicidade retal tardia ocorreu como grau 1 em 3,4% dos pacientes; como grau 2, em 1,5%; como grau 3, em 0,3%; e como grau 4, em 0,3%. O risco para toxicidades retais agudas e tardias foi maior quando teleterapia conformada foi utilizada. Foi observada dor na glande em 4,9% dos pacientes e 71% apresentaram disfunção erétil tardiamente. O uso de Sildenafil foi eficiente em 59%. Pacientes mais velhos, ou com uma ou mais comorbidades, comprometimento prévio da ereção, ou que receberam radioterapia externa conformada apresentaram maior incidência de disfunção erétil. CONCLUSÕES: a associação de BATD como um reforço de dose para teleterapia mostrou ser um método viável e seguro apresentando boa eficácia e toxicidade aceitável. Os fatores relacionados à sobrevida e toxicidade podem colaborar na melhor seleção e tratamento de pacientes com câncer de próstata localizado. / INTRODUCTION: high dose-rate brachytherapy (HDR) for prostate cancer may be a nice treatment option for dose escalation as a boost, when associated to external beam irradiation, mainly if 3D conformal or more advanced technology is not available. PURPOSE: this study analyzes the results and toxicities of HDR brachytherapy boost prior to external beam radiotherapy with 2D or 3D conformal irradiation in patients with localized prostate cancer. Prognostic factors associated to overall and disease-free survival, as well as to treatment related toxicity were also studied. METHODS: A retrospective study of 403 patients with localized prostate adenocarcinoma treated between December 2000 and March 2004 was performed. According to the risk group, three fractions of HDR brachytherapy were delivered in the course of 24 hours, with a single implant: 5.5 to 6 Gy per fraction for low risk, 6 to 6.5 Gy per fraction for intermediate risk, and 6.5 to 7 Gy per fraction for high risk patients. The interval between fractions was of at least 6 hours. Conventional 2D or 3D conformal external beam irradiation was delivered to the prostate and seminal vesicles with 25 fractions of 1.8Gy (45Gy), about 2 weeks after brachytherapy. Multivariate analysis was done to evaluate unfavorable prognostic factors for biochemical failure free survival (BFFS). RESULTS: Patients presented a median age of 68 years, mean PSA of 9g/ml, and average prostate weight of 35 cc. Gleason score was equal to 6 in 43% of the cases, and 97% of the cases were at a stage lower than T2c. Prostate nodules were present in 49% of the patients; prior history of transurethral resection or urinary obstruction was present in 11% and 16% of the patients, respectively. There were 36.1% patients in the low risk group, 42.8% in the intermediate, and 21.1% in the high risk groups, respectively. Up to six months of neoadjuvant hormone therapy was used in 64% of the cases. External beam radiation was delivered with 3D conformal radiation in 19% of patients. The mean follow-up was 50 months ranging from 24 to 113 months (median 48,4 months). Nine patients (2.2%) did not respond to treatment. Death from prostate cancer occurred in 4.5% of the cases in a mean period of 22 months. Biochemical failure occurred in 9.6% according to both ASTRO and Phoenix consensus criteria. However, the mean time to relapse was 13 months using the ASTRO criteria and 26 months with the Phoenix definition. The five-year BFFS using the ASTRO criteria was 94.3%, 86.9% and 86.6% for the low, intermediate and high risk groups, respectively. Using the Phoenix criteria, 92.4%, 88.0% and 85.3% for the low, intermediate and high risk groups, respectively (p = 0.109). The only feature predicting biochemical failure (BF) in the multivariate analysis by both ASTRO and Phoenix criteria was the presence of prostate nodules, but patients younger than 60 years presented higher chance of BF using Phoenix criteria only. Acute urinary toxicities as urinary retention and hematúria occurred respectively in 2.8% and 1.3% of the patients. They presented as grade 1 in 23.7%, grade 2 in 15.1% and grade 3 in 2%. Late urethral stenosis was observed in 8.5% and late urinary toxicity was grade 1 in 8.8% of the patients, grade 2 in 3.9%, grade 3 in 7.7% and grade 4 in 0.3%. Acute urinary toxicity was related to previous urinary obstruction and higher brachytherapy dose to the urethra. Late urethral stenosis was related to older age and higher brachytherapy dose. Grade 1 early rectal toxicity occurred in 14.8% of the patients, grade 2 in 10.5% and grade 3 in 1.3%. Late rectal toxicity occurred as grade 1 in 3.4% of patients, as grade 2 in 1.5%, grade 3 in 0.3% and grade 4 in 0.3%. The risk of acute and late rectal toxicity was higher when 3D conformal irradiation was used. Glans pain was observed in 4.9% of the patients. Late sexual impotence occurred in 71% of cases. Sildenafil was effective in 59%. Sexual impotence presented a higher incidence in older patients with one or two co-morbidities, previous sexual impairment, or 3D conformal irradiation. CONCLUSIONS: the association of HDR brachytherapy as a boost for external beam irradiation seems to be a feasible and safe procedure, with good efficacy and acceptable toxicity. Factors related to survival and toxicity can help to better select and manage patients with localized prostate carcinoma.

by Yiu-bong Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 67-68). / Abstract --- p.i / Acknowledgment --- p.ii / Abbreviation --- p.iii / List of spectra --- p.iv / Contents --- p.v / Chapter Part 1: --- A New Synthesis of Rhodium(II) and Iridium(II) Octaethyl- porphyrin Dimers / Chapter 1.1 --- Introduction / Chapter 1.1.1 --- Objective --- p.1 / Chapter 1.1.2 --- Literature Survey --- p.1-7 / Chapter 1.2 --- Result and Discussion --- p.8-10 / Chapter 1.3 --- Conclusion --- p.11 / Chapter Part 2: --- Substituent Effect of meso-pαrα-Arylsubstituted Octabromo- tetraphenylporphyrins / Chapter 2.1 --- Introduction / Chapter 2.1.1 --- Objective --- p.12 / Chapter 2.1.2 --- Literature Survey --- p.12-17 / Chapter 2.2 --- Result and Discussion --- p.18-28 / Chapter 2.3 --- Conclusion --- p.29 / Chapter Part 3: --- "Thermolysis of [2，3，7，8,12,13,17,18-0ctachloro-5,10,15,20- tetrakis(4'-tert-butylphenyl)porphyrinato]-2-phenylethyl- rhodium(III)" / Chapter 3.1 --- Introduction / Chapter 3.1.1 --- Objective --- p.30 / Chapter 3.1.2 --- Literature Survey --- p.30-31 / Chapter 3.2 --- Result and Discussion --- p.32-45 / Chapter 3.3 --- Conclusion --- p.46 / Experimental Section --- p.47-64 / References --- p.65-68 / Spectra --- p.69-83

Catalisadores de Ir/Al2O3, Ir-Ru/ Al2O3 e Ru/ Al2O3 com teores metálicos próximos a 30% em peso, foram preparados em vinte etapas de impregnação utilizando-se uma alumina sintetizada no LCP/INPE como suporte. Os catalisadores de Ir e Ir-Ru foram preparados a partir de soluções contendo precursores metálicos clorados pelo método de impregnação incipiente. Os catalisadores de Ru foram preparados a partir de dois precursores metálicos: um clorado e um precursor orgânico. Neste caso, o catalisador originado do precursor clorado foi preparado por impregnação incipiente, enquanto que o catalisador originado do precursor orgânico foi preparado pelo método de impregnação por excesso de volume. Todos os catalisadores foram caracterizados antes e depois dos testes em micropropulsor pelas técnicas: absorção atômica, para a determinação do teor metálico; fisissorção de nitrogênio, para determinações de área específica e distribuição do volume de mesoporos; quimissorção de hidrogênio e MET, para determinações da dispersão e do diâmetro médio das partículas metálicas (dQH e dMET). Os catalisadores foram testados na reação de decomposição de hidrazina em micropropulsor e comparados com o catalisador comercial Shell 405. Os resultados mostraram que os catalisadores contendo Ir apresentaram desempenho similar ao catalisador comercial e que os catalisadores de Ru não devem ser usados em partidas frias. / Ir/Al2O3, Ir-Ru/ Al2O3 and Ru/ Al2O3 catalysts with metallic loading of c. a. 30 %wt., were prepared in twenty impregnation steps using an alumina synthesized at LCP/INPE as support. The Ir and Ir-Ru catalysts were prepared from metallic chloride precursors solutions by incipient impregnation method. The Ru catalysts were prepared from two metallic different precursors: a chloride precursor and an organic precursor. In this case, the catalyst originated from the chloride precursor was prepared by the incipient impregnation method, while the catalyst originated from the organic precursor was prepared by volume excess impregnation method. All the catalysts were characterized before and after the microthruster tests by the following techniques: atomic absorption, for metallic content determination; nitrogen physiosorption, for specific area and mesoporous volume distribution; hydrogen chemisorption and TEM, for dispersion and metallic particles average diameter (dQH and dMET ). The catalysts were tested by the hydrazine decomposition reaction in microthruster and compared with commercial catalyst Shell 405. The results showed that the performance of Ir catalysts are similar to the commercial ones and the Ru catalysts should not be used in cold startups.

Neste trabalho foram preparados materiais constituídos por Al2O3 e Nb2O5, na forma de grãos esferoidais para serem usados como suporte de catalisadores aplicados à propulsão. Os suportes foram preparados por quatro diferentes métodos: impregnação úmida do óxido de alumínio moldado por uma solução alcoólica de cloreto de nióbio (NbCl5); impregnação seca do óxido de alumínio por uma solução alcoólica de NbCl5; co-precipitação dos precursores de óxido de alumínio e óxido de nióbio; e mistura física dos precursores desses óxidos previamente autoclavados separadamente. Entre esses métodos, os suportes que apresentaram melhores características para aplicação em propulsão a monopropelente hidrazina (N2H4) foram aqueles preparados por mistura física, contendo 20% m/m de óxido de nióbio (Su20MF) e por impregnações secas sucessivas, contendo 10% m/m de óxido de nióbio (Su10IS). A adição do óxido de nióbio ao óxido de alumínio resultou em acentuado aumento da resistência mecânica à compressão, mas não causou variação significativa do número e força dos sítios ácidos de Lewis, em função dos tratamentos de calcinação efetuados a 873 K por 5 horas. Todos os suportes foram impregnados com solução de H2IrCl6 e após tratamentos de redução sob H2, obteve-se catalisadores de irídio suportados, com elevados teores metálicos, CAT-20Ir, contendo aproximadamente 20% m/m de Ir disperso na superfície do suporte Su10IS, e CAT-27Ir, contendo aproximadamente 27% m/m de Ir disperso na superfície do suporte Su20MF. Caracterizações por quimissorção de H2 e por MET/EDS mostraram que o irídio fixou-se quase que exclusivamente sobre o óxido de alumínio, gerando partículas metálicas com diâmetros médios tanto maiores quanto menores as áreas superficiais expostas desse óxido. Testes efetuados em bancada com as reações de decomposição de hidrazina e de amônia revelaram que a reação com hidrazina ocorre de forma completa em temperaturas acima de 393 K, gerando exclusivamente amônia e nitrogênio, enquanto que a decomposição da amônia inicia-se em temperaturas superiores e diferenciadas, dependendo do catalisador. Durante a reação da hidrazina, a reação de decomposição da amônia formada, produzindo hidrogênio foi acompanhada, sendo tanto menor quanto maior o diâmetro médio das partículas de irídio, sendo que a seletividade ao hidrogênio mostrou ser uma função linear do diâmetro médio, ao menos entre 24 Å e 40 Å. Esse comportamento se deve ao fato de que a decomposição da amônia é uma reação sensível à estrutura da fase ativa destes catalisadores. Já os testes efetuados em propulsores de 5 N de empuxo no Banco de Teste com Simulação de Altitude (BTSA), evidenciaram um aumento da temperatura, da pressão de câmara e também da força de empuxo, devido à menor decomposição da amônia e maiores tempos para o início da decomposição da hidrazina, efeito este relacionado ao número específico de sítios ativos presentes nas superfícies dos catalisadores. / In this work were prepared supports consisting of Al2O3 and Nb2O5, in the form of spheroidal grains by four different methods: wet impregnation of the aluminum oxide molded an alcoholic solution of niobium chloride (NbCl5); dry impregnation of aluminum oxide in an alcoholic solution of NbCl5; co-precipitation of the precursor of aluminum oxide and niobium oxide; and physical mixing of precursors of these oxides previously autoclaved separately. Among these methods, the supports that showed the best characteristics for application in propulsion monopropellant hydrazine were those prepared by physical mixture containing 20 wt % niobium oxide (Su20MF) and successive dry impregnations, containing 10 wt % niobium oxide (Su10IS).The addition of niobium oxide in aluminum oxide resulted in a significant increase in compressive strength of these selected supports, but caused no significant change in the number and strength of Lewis acid site, which was attributed to the calcination treatment carried out at 873 K by 5 hours. These supports were impregnated with H2IrCl6 solution and after reduction treatment under H2, were obtained supported iridium catalysts with high metal contents, named CAT-20Ir containing approximately 20 wt % of Ir dispersed on the support Su10IS and CAT-27Ir containing approximately 27 wt % of Ir Su20MF dispersed on the support. Characterization by chemisorption of H2 and by TEM/EDS showed that the iridium was anchored almost exclusively on aluminum oxide, generating metal particles with average diameters greater. Tests carried out in laboratory with decomposition of hydrazine and ammonia revealed that the reaction with hydrazine is completely in temperatures above 393 K, generating only ammonia and nitrogen, while the decomposition of ammonia, the reaction initiation above different temperatures depending on the catalyst. During decomposition hydrazine another accompanied reaction was the decomposition of ammonia generated, producing hydrogen. The selectivity to hydrogen showed to be a linear function of the mean diameter particle of iridium, least between 24 Å and 40 Å , these results were attributed to the fact that the decomposition of ammonia is a sensitive reaction to the structure of the active phase of these catalysts. Tests carried out at the Altitude Simulation Test Facility (BTSA/INPE) showed the following effects caused by Nb2O5 addition to iridium catalyst supports: increase of temperature, chamber pressure and thrust power, due to a smaller ammonia decomposition; and increase of time for hydrazine decomposition when there is an excessive reduction of the specific number of active sites.

Catalisadores de Ir/Al2O3, Ir-Ru/ Al2O3 e Ru/ Al2O3 com teores metálicos próximos a 30% em peso, foram preparados em vinte etapas de impregnação utilizando-se uma alumina sintetizada no LCP/INPE como suporte. Os catalisadores de Ir e Ir-Ru foram preparados a partir de soluções contendo precursores metálicos clorados pelo método de impregnação incipiente. Os catalisadores de Ru foram preparados a partir de dois precursores metálicos: um clorado e um precursor orgânico. Neste caso, o catalisador originado do precursor clorado foi preparado por impregnação incipiente, enquanto que o catalisador originado do precursor orgânico foi preparado pelo método de impregnação por excesso de volume. Todos os catalisadores foram caracterizados antes e depois dos testes em micropropulsor pelas técnicas: absorção atômica, para a determinação do teor metálico; fisissorção de nitrogênio, para determinações de área específica e distribuição do volume de mesoporos; quimissorção de hidrogênio e MET, para determinações da dispersão e do diâmetro médio das partículas metálicas (dQH e dMET). Os catalisadores foram testados na reação de decomposição de hidrazina em micropropulsor e comparados com o catalisador comercial Shell 405. Os resultados mostraram que os catalisadores contendo Ir apresentaram desempenho similar ao catalisador comercial e que os catalisadores de Ru não devem ser usados em partidas frias. / Ir/Al2O3, Ir-Ru/ Al2O3 and Ru/ Al2O3 catalysts with metallic loading of c. a. 30 %wt., were prepared in twenty impregnation steps using an alumina synthesized at LCP/INPE as support. The Ir and Ir-Ru catalysts were prepared from metallic chloride precursors solutions by incipient impregnation method. The Ru catalysts were prepared from two metallic different precursors: a chloride precursor and an organic precursor. In this case, the catalyst originated from the chloride precursor was prepared by the incipient impregnation method, while the catalyst originated from the organic precursor was prepared by volume excess impregnation method. All the catalysts were characterized before and after the microthruster tests by the following techniques: atomic absorption, for metallic content determination; nitrogen physiosorption, for specific area and mesoporous volume distribution; hydrogen chemisorption and TEM, for dispersion and metallic particles average diameter (dQH and dMET ). The catalysts were tested by the hydrazine decomposition reaction in microthruster and compared with commercial catalyst Shell 405. The results showed that the performance of Ir catalysts are similar to the commercial ones and the Ru catalysts should not be used in cold startups.

京都大学 / 新制・課程博士 / 博士(人間・環境学) / 甲第23991号 / 人博第1043号 / 新制||人||245(附属図書館) / 2022||人博||1043(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 藤田 健一, 教授 小松 直樹, 教授 津江 広人, 教授 大江 洋平 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM