Orientadores: Antonio Jose Gomez Cobo, Wagner Alves Carvalho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-13T07:06:47Z (GMT). No. of bitstreams: 1 Zanutelo_Cristiane_M.pdf: 6296648 bytes, checksum: d0a5733122c9f01d2f0c76ea9acfe714 (MD5) Previous issue date: 2009 / Resumo: A hidrogenação parcial do benzeno é uma reação química de interesse industrial, uma vez que o cicloexeno obtido pode ser empregado para a produção de diversos produtos. Além disso, ainda encontra uma importante aplicação na proteção ambiental, face às severas restrições à presença de compostos aromáticos nos combustíveis. O presente trabalho tem o objetivo de estudar a influência do tratamento aplicado ao suporte no desempenho de catalisadores de Ru sobre carvão ativado, destinados à reação de hidrogenação parcial do benzeno em fase líquida. Para tanto, um carvão ativado comercial foi submetido a diferentes tratamentos físicos e/ou químicos. Os sólidos obtidos foram empregados como suporte na preparação de catalisadores 5 % Ru/C. Os catalisadores foram preparados através de impregnação à seco, partindo-se de uma solução aquosa do precursor RuCl3.xH2O. Após impregnação, alguns catalisadores foram submetidos a uma redução direta sob H2, à temperatura de 423 K, com o intuito de avaliar os efeitos de tal tratamento de ativação. Os suportes preparados foram caracterizados através da adsorção de N2 (método de B.E.T.), titulação de Boehm, titulação potenciométrica e da determinação da entalpia de imersão em água. A espectroscopia de fotoelétrons excitados por raios X foi utilizada para estudar a superfície de suportes e catalisadores, enquanto que a microscopia eletrônica de varredura possibilitou determinar a composição química e observar a morfologia dos catalisadores. O desempenho dos catalisadores de Ru/C foi avaliado na reação de hidrogenação do benzeno em fase líquida, empregando-se um reator Parr do tipo "slurry". A reação foi conduzida sob pressão total de 5,0 MPa de H2, à temperatura de 373 K e com a presença de água no meio reacional. Os resultados obtidos indicam que o desempenho catalítico do sistema Ru/C é influenciado por determinados grupos funcionais presentes na superfície do carvão ativado. Os grupos carbonila diminuem a atividade e a seletividade da reação, enquanto que um aumento dos grupos carboxílicos conduz a catalisadores mais ativos e a maiores rendimentos em cicloexeno. / Abstract: The partial hydrogenation of benzene is a chemical reaction of industrial interest, as the cyclohexene obtained may be used to production of several products. Moreover, it also finds important application in the ambient protection, face to the severe restrictions to the aromatical composite presence in fuels. The aim of the present work is to study the influence of the treatment applicated the support on the performance of Ru catalysts on activated charcoal, to the benzene partial hydrogenation reaction in liquid phase. Therefore, commercial activated charcoal was submitted by means of different physical and/or chemical treatments. The solids obtained were used as support to the preparation of 5 wt.% Ru/C catalysts. The catalysts were prepared by incipient wetness impregnation method, through an aqueous solution of the precursor RuCl3.xH2O. After impregnation, some catalysts were submitted a direct reduction in H2 atmosphere at the temperature of 423 K, in order to evaluate the effects of such treatment of activation. The supports prepared were characterized by N2 adsorption (B.E.T. method), Boehm's titration, potenciometric titration and determination of the enthalpy of immersion in water techniques. The X-ray photoelectron spectroscopy technique was used to study the surface of supports and catalysts, whereas the electronic scanning microscopy allowed to determine the chemical composition and observe the morphology of the catalysts. The performance of the Ru/C catalysts was evaluated in the benzene hydrogenation reaction, using a Parr reactor of type "slurry". The reaction was conducted under total pressure of 5,0 MPa of H2 at a temperature of 373 K, with the presence of water in reactional medium. The results obtained indicate that the catalytic performance of the system Ru/C is influenced for determined functional groups present on the surface of activated charcoal. The carbonyl groups decrease the activity and selectivity of the reaction, while an increase of the carboxylic groups leads to more active catalysts and the highest yield of cyclohexene. / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Orientador: Antonio Jose Gomez Cobo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-15T16:04:26Z (GMT). No. of bitstreams: 1 Suppino_RaphaelSoeiro_M.pdf: 3682407 bytes, checksum: 9e1b8ac86459e6d0a450f3e0aaea6013 (MD5) Previous issue date: 2010 / Resumo: A reação de hidrogenação parcial do benzeno em fase líquida tem sido estudada com vistas à obtenção do cicloexeno. Este produto de alto valor agregado pode ser utilizado para a obtenção de poliamidas, como o nylon, através de uma rota industrialmente simples e ecologicamente correta. Esta reação possui ainda uma importante aplicação na proteção ambiental, face às severas restrições à presença de compostos aromáticos nos combustíveis. O presente trabalho tem por objetivo estudar o desempenho de catalisadores de Ru/Al2O3 e Ru/CeO2 preparados através dos métodos de impregnação incipiente e impregnação úmida. Objetiva-se ainda estudar os efeitos da adição de solventes orgânicos ao meio reacional, e a utilização dos solventes na separação dos produtos da reação. Os catalisadores estudados foram preparados a partir de soluções aquosas de RuCl3.xH2O. No caso da impregnação incipiente, os sólidos foram secos a 358 K por 24 h e reduzidos sob fluxo de H2 a 573 K por 3 h. No caso da impregnação úmida, os catalisadores foram reduzidos com formaldeído a 353 K, durante a impregnação. Os suportes Al2O3 e CeO2 foram caracterizados através de titulação potenciométrica e a adsorção de N2 (método de B.E.T.) foi empregada para determinar a área específica dos sólidos. As técnicas de MEV+EDX e XPS permitiram avaliar a composição dos sólidos, enquanto que a formação da fase ativa dos catalisadores foi estudada através de TPR. O desempenho dos catalisadores foi avaliado na reação de hidrogenação parcial do benzeno em fase líquida, conduzida à pressão constante de 5 MPa de H2 e a 373 K num reator Parr do tipo slurry. A destilação extrativa dos produtos de reação foi estudada com o software Aspen Plus®. Os resultados obtidos indicam que os catalisadores de Ru/Al2O3, preparados por impregnação úmida, apresentam os melhores desempenhos catalíticos nesta reação. O rendimento de cicloexeno aumenta com a adição de solvente ao meio reacional, segundo a ordem: monoetanolamina > monoetilenoglicol > n-metil-2-pirrolidona > acetato de etila. Nas condições deste estudo o monoetilenoglicol foi o único solvente capaz de separar todos os produtos de reação com eficiência suficiente para um processo industrial / Abstract: The reaction of partial hydrogenation of benzene in liquid phase has been studied with the purpose of obtaining cyclohexene. This product of high aggregated value can be used to obtain polyamides such as nylon, through a route industrially simple and environmentally friendly. This reaction also has an important application in environmental protection, given the severe restrictions on the presence of aromatics in fuels. In this context, this work aims to study the performance of Ru/Al2O3 and Ru/CeO2 catalysts prepared by the methods of incipient impregnation and wet impregnation. Another object of the present work is to study the effects of adding organic solvents to the reaction medium, and the use of these solvents for the separation of reaction products. The catalysts were prepared from aqueous solutions of RuCl3. xH2O. In the case of incipient impregnation, the solids were dried at 358 K for 24 h and reduced under H2 flow at 573 K for 3 h. In the case of wet impregnation, the catalysts were reduced with formaldehyde at 353 K during the impregnation step. The supports Al2O3 and CeO2 were characterized by potentiometric titration and N2 adsorption (B.E.T. method) was used to determine the specific area of the solids. The techniques of SEM + EDX and XPS allowed the evaluation of the composition of solids, whereas the formation of the active phase of catalysts was studied by TPR. The performance of the catalysts was evaluated in the liquidphase partial hydrogenation of benzene carried out at H2 constant pressure of 5 MPa and 373 K in a slurry Parr reactor. The extractive distillation of the reaction products was studied with the software Aspen Plus ®. The results indicate that the catalysts Ru/Al2O3, prepared by wet impregnation, led to the best performances observed for this reaction. The yield of cyclohexene increases with the addition of solvent to the reaction medium, following the order: monoethanolamine > monoethylene glycol > n-methyl-2-pyrrolidone > ethyl acetate. In this study, monoethylene glycol was the only solvent able to efficiently separate all reaction products to obtain cyclohexene in an industrial process / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Orientador: Antonio Jose Gomez Cobo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-11T16:03:38Z (GMT). No. of bitstreams: 1 Rodrigues_MichelleFernandaFaita_M.pdf: 1374459 bytes, checksum: ee724b305981f732c54098cdcd569738 (MD5) Previous issue date: 2008 / Resumo: No presente trabalho, tem-se por objetivo estudar os efeitos da morfologia do suporte, notadamente do diâmetro da partícula e da área específica, sobre o desempenho de catalisadores de Ru/Al2O3 e Ru/Nb2O5 destinados à reação de hidrogenação parcial do benzeno em fase líquida. Para tanto, catalisadores de Ru/Al2O3 e Ru/Nb2O5 foram preparados através de impregnação incipiente, a partir de uma solução aquosa do precursor RuCl3.xH2O, empregando-se os respectivos suportes com granulometrias e áreas específicas diversas. Após impregnação, os sólidos foram secos a 358 K, por um período de cerca de 24 h. A seguir, os sólidos foram submetidos a um tratamento de redução direta sob H2, à temperatura de 573 K. Os sólidos obtidos foram caracterizados através das técnicas Mastersizer-Distribuição do Tamanho de Partícula, Difração de Raios-X, Adsorção de N2 (método B.E.T.), Microscopia Eletrônica de Varredura com Microssonda para Análise Espectrométrica de Raios-X e Redução à Temperatura Programada. Os desempenhos catalíticos foram avaliados na reação de hidrogenação do benzeno, empregando-se um reator Parr do tipo ¿slurry¿. A reação foi conduzida sob pressão constante de 5,0 MPa de H2 e à temperatura de 373 K, em meio reacional trifásico contendo água. Para as condições empregadas neste estudo, os resultados obtidos mostram que praticamente não há influência da natureza dos suportes Al2O3 e Nb2O5 sobre a seletividade de cicloexeno. No entanto, o aumento do diâmetro de partícula ou da área específica do suporte diminui o rendimento do produto desejado / Abstract: The principal aim of the present work is to study the effects of the morphology of supports, especially the particle diameter and the specific area on the performance of catalytic Ru/Al2O3 and Ru/Nb2O5 for partial hydrogenation reaction of benzene in liquid phase. Therefore, Ru/Al2O3 and Ru/Nb2O5 catalysts were prepared by incipient wetness impregnation, from an aqueous solution of RuCl3.xH2O chlorinated precursor, using supports with several granulometries and specific areas. After impregnation, the solids were dried at 358 K, for a period of 24 h. Then the solid underwent a treatment to direct reduce under H2, at the temperature of 573 K. The solid results were characterized by technical Mastersizer-Particle size Analysis, Diffraction of X-rays, adsorption of N2 (BET method), Electronic Scanning Microscopy and Temperature Programmed Reduction (TPR). The performances were evaluated in the catalytic reaction of benzene hydrogenation, using a reactor Parr of the "slurry". The reaction was conducted under constant pressure of 5.0 MPa of H2 and a temperature of 373 K, in a three-phase reactional medium with water. For the conditions employed in this study, the results show that virtually no influence the nature of the Al2O3 and Nb2O5 supports on the ciclohexene selectivity. However, the increase in the diameter of particle or the specific area of support decreases the yield of the desired product / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Orientadores: Meuris Gurgel Carlos da Silva, Onelia Aparecida Andreo dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-24T22:59:54Z (GMT). No. of bitstreams: 1 Bedin_Sidmara_M.pdf: 4205652 bytes, checksum: d622e46268c9acb2352410201461233c (MD5) Previous issue date: 2014 / Resumo: Diariamente, uma grande quantidade de fluxos de água sofre contaminação por compostos orgânicos como, por exemplo, o benzeno, tolueno e xileno (BTX), os quais são compostos tóxicos e nocivos ao meio ambiente e aos seres humanos. Sendo assim, o estudo de técnicas de remoção e tratamento desses poluentes vem se tornando tema de muitas pesquisas. A adsorção tem se mostrado uma técnica bastante eficiente, pois atende aos limites da legislação, apresenta baixo consumo energético e custo de processo, ainda mais quando se faz uso de um adsorvente alternativo, como é o caso da argila organofílica. Nesse trabalho foi proposto avaliar a argila esmectítica sódica nacional Fluidgel, na forma natural e organofilizada, como materiais adsorventes alternativos na remoção dos compostos orgânicos BTX de soluções aquosas, em ensaios em sistema batelada e em sistema dinâmico. A argila organofílica foi preparada a partir da argila comercial e do sal quaternário de amônia HDTMA e se verificou a capacidade de troca catiônicas dos adsorventes. Foram realizadas técnicas de caracterização com a finalidade de determinar a área superficial do material, estrutura de poros, estrutura cristalina, morfologia de superfície, composição química, perda de massa e água e identificação de grupos funcionais de superfície. Testes preliminares comprovaram o caráter hidrofóbico da argila organofílica e sua afinidade por compostos orgânicos, bem como o caráter hidrofílico da argila comercial. Ensaios cinéticos de pH mostraram que o mesmo não afeta de maneira significativa o processo de adsorção. Os ensaios cinéticos de adsorção realizados em sistema batelada alcançaram o equilíbrio em 3h e apresentaram porcentagens de remoção de poluente superiores a 90%, com concentração inicial de 1,09 mmol/L. Os modelos cinéticos analisados foram o de pseudoprimeira ordem, pseudossegunda ordem e o de difusão intrapartícula, sendo que o modelo de pseudossegunda ordem melhor descreveu os dados experimentais. Para as isotermas de equilíbrios, testou-se as temperaturas de 35, 25 e 15 oC, sendo a maior capacidade de remoção com a maior temperatura, indicando que a adsorção nesse caso é de natureza endotérmica. Os modelos de isotermas avaliados foram Langmuir, Freundlich, Sips, DSL, MSAM e D-R, porém apenas o modelo de D-R descreveu de maneira satisfatória os dados experimentais. Pela análise dos parâmetros termodinâmicos, verificou-se que o processo de adsorção em estudo é espontâneo, favorecido a altas temperaturas e que possivelmente ocorre fisissorção. Devido à alta volatilidade dos compostos BTX, foi feita uma adaptação na adsorção em sistema dinâmico através de coluna de leito fixo e se realizou um ensaio cinético em leito de adsorção. A ordem de remoção dos compostos orgânicos, para ambas as argilas, foi xileno > tolueno > benzeno / Abstract: Daily a large amount of water flows suffers contamination by organic compounds as, for example, benzene, toluene and xylene (BTX), which are toxic compounds and harmful to the environment and to humans. Thus, the study of techniques for removal and treatment of these pollutants has become the subject of much research. The adsorption has proven to be a very effective technique because it meets the limits of the law, has low energy consumption and process cost, further when it makes use of an alternative adsorbent, as is the case with organoclay. In this study, it was proposed evaluate the national sodium smectite clay Fluidgel , in the natural and organophilizated form, as an alternative adsorbent material to the removal of organic compounds BTX from aqueous solutions in batch and dynamic system essays. The organoclay was prepared from the commercial clay and the quaternary ammonium salt HDTMA and it was verified the cationic exchange capacity of the adsorbents. Were performed characterization techniques in order to determine the surface area of the material, pore structure, crystal structure, surface morphology, chemical composition, mass and water loss and identification of surface functional groups. Preliminary tests confirmed the hydrophobic character of the organoclay and their affinity for organic compounds and the hydrophilic character of the commercial clay. pH kinetic experiments showed that the same does not affect significantly the adsorption process. Kinetic assays of adsorption performed in batch system reached equilibrium in 3 hours and showed pollutant removal percentages greater than 90%, with an initial concentration of 1.09 mmol/L. The kinetic models analyzed were the pseudo first order, pseudo second order and the intraparticle diffusion, being that the pseudo second order model best described the experimental data. For the equilibrium isotherm, was tested at temperatures of 35, 25 and 15 °C, being the largest removal capacity with the greatest temperature, indicating that the adsorption of this case is endothermic in nature. The isotherm models evaluated were Langmuir, Freundlich, Sips, DSL, MSAM and D-R, but only the D-R model described satisfactorily the experimental data. By the analysis of the thermodynamic parameters, it was found that the adsorption in study is spontaneous and favorable at high temperatures and that possibly occurs physisorption. Due to the high volatility of BTX compounds, it was made an adaptation to dynamic adsorption system through fixed bed column and a kinetic assay was carried out in adsorption bed. The order of removal of organic compounds for both clays was xylene > toluene > benzene / Mestrado / Engenharia Química / Mestra em Engenharia Química

Orientador: Antonio Jose Gomez Cobo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-03T03:39:51Z (GMT). No. of bitstreams: 1 Zonetti_PrisciladaCosta_M.pdf: 2908530 bytes, checksum: 3f02518e296dab156d7d4910c2097277 (MD5) Previous issue date: 2003 / Resumo: O presente trabalho tem como principal objetivo estudar a influência das condições de ativação (calcinação e redução) sobre o desempenho de catalisadores Ru/Ce02, destinados à reação de hidrogenação parcial do benzeno para a obtenção de cicloexeno. Para tanto, catalisadores de RulCe02 foram preparados pelo método da impregnação a seco, partindo-se de uma solução aquosa do precursor metálico RuCl3/xH20. Após a impregnação, os sólidos foram secos a 358K, por um período aproximadamente de 24 h. A seguir, os catalisadores foram submetidos aos tratamentos de calcinação em atmosfera de ar nas temperaturas de 473K e 673K, e/ou reduzidos em atmosfera de H2 nas temperaturas de 523K, 773K e 1023K. Os sólidos obtidos foram caracterizados por meio das técnicas de análise termogravimétrica, medida de área superficial específica (método B.E.T.), difração de raios X, quimissorção de O2, RTP e XPS. O desempenho dos catalisadores foi avaliado na reação de hidrogenação do benzeno, empregando-se um reator trifásico do tipo leito de lama ("slurry"). A reação foi conduzida sob pressão constante de 5,0 MPa de H2 e à temperatura de 373K, em meio reacional trifásico, contendo água e o aditivo TiC3. Os perfis de TPR dos catalisadores preparados sugerem que uma oxidação profunda do Ru é induzida pelo tratamento de calcinação. Os resultados das análises de XPS confirmam tal suposição, mostrando que o rutênio se encontra na forma de RU02 na amostra calcinada a 673K, enquanto que no sólido reduzido a 773K tem-se Ru no estado metálico. No entanto, a etapa de calcinação, seguida ou não de redução, é fortemente prejudicial ao desempenho catalítico, provavelmente devido à forte oxidação do rutênio, a qual pode ser promovida pelo suporte Ce02. Por sua vez, a redução direta conduz a catalisadores RulCe02 mais ativos, bem como a maiores rendimentos em cicloexeno, ao longo de toda a reação / Abstract: The aim of the present work is to study the influence of the activation conditions (calcination and reduction) on the performance of Ru/CeO2 catalysts, to the benzene partial hydrogenation reaction for cyc1ohexene production. Therefore, Ru/CeO2 catalysts were prepared by incipient wetness impregnation method, through an aquous solution of the RuChxH20 metallic precursor. After the impregnation, the solids were dried at 358K, for a period of 24h. To follow, the catalysts were submitted to the treatments of calcination in air atmosphere at the temperatures of 473K and 673K and/or reduction in H2 atmosphere at the temperatures of 523K, 773K and 1023K. The solids obtained were characterized by means of termogravimetric analysis, measure ofn specific superficial area (BET method), x-ray diffraction, oxygen chemisorption, RTP and XPS techniques. The performance of the catalysts was evaluated in the benzene hydrogenation reaction, with a slurry three-phase reactor. The reaction was lead under constant H2 pressure of 5,OMPa at the temperature of 373K, in a three-phase reactional medium with water and TiCl3 additive. RTP profiles of the prepared catalysts suggest that a deep oxidation of the Ru is induced for the ca1cination treatment. The results of the XPS analyses confirm such assuption, showing that in the ca1cinated sample at 673K the ruthenium form is RUO2, while in the solid reduced at 773K there is Ru in its metallic state. Howerer, the ca1cination step, followed or not of reduction, is strongly harmful to the catalytic perfomance. That is probably due to strong oxidation of the ruthenium, which can be promoted by the CeO2 support. In turn, the direct reduction leads to Ru/CeO2 catalysts more actives, as well as to higher yields of cyc1ohexene, throughout all the reaction / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

In the United States, approximately 3% of infants are diagnosed with a major birth defect each year. Whereas prevention efforts have led to decreases in some birth defects, the cause of approximately 70% of birth defects remains unknown. More recently, there has been increasing concern regarding exposures to environmental agents, such as air pollution during pregnancy, and the risk of birth defects. Over the past decade, there has been an increase in research studies examining the association between air pollution and birth defects. The results have been inconsistent, with some studies reporting that higher levels of exposure from the same pollutant increase the risk of birth defects, whereas others report no risk or even a decrease in risk. These inconsistencies may arise from differences in exposure assessment methods across epidemiological studies. A comprehensive series of sensitivity analyses were conducted to evaluate the impact of different exposure estimation decisions on the adjusted measures of associations between ambient air pollution exposure and birth defects. For each of six decisions – spatial scale, spatial limit, temporal scale, temporal limit, data aggregation sequence, and weighting scheme – two alternative choices were considered, and maternal exposure to PM2.5 and benzene were estimated for each ‘sensitivity case' (unique combination of choices across all decisions). For each sensitivity case, adjusted prevalence ratios (aPRs) and 95% confidence intervals (CI) were estimated from multivariable regression models comparing each exposure quartile to the first quartile; each measure of association represented the associations between either benzene or PM2.5 and one of the birth defects under study. To then evaluate the impact of selecting alternative choices for each exposure assessment decision, three metrics were used: 1) the percent difference in the aPR point estimates between alternative choices for a specific decision (calculated for each sensitivity case pairing); 2) the percent of sensitivity cases in which the aPR 95% CIs for alternative choices for a specific decision overlapped (i.e., were not statistically significantly different); and 3) the percent of sensitivity cases in which there was agreement in the substantive conclusion of the association between exposure (pollutant) and outcome (defect), the conclusion being either statistically significant increased risk, statistically significant decreased risk, or no statistically significant difference in risk. Second, a retrospective cohort study was conducted to investigate the association between maternal exposure to ambient benzene and PM2.5 and the risk of musculoskeletal birth defects in offspring. For both analyses, data on singleton infants born from 2000 to 2013 were obtained from the Florida Birth Defects Registry and air pollution data were obtained from the Environmental Protection Agency Air Quality System database. Exposure estimates were calculated for all birth defect cases and non-affected births during etiologically relevant time windows and multivariable regression models were used to obtain aPRs and 99% CIs comparing each quartile of exposure to the first. For PM2.5, across all exposure-outcome pairs under study, the alternative choices for the decision of spatial scale resulted in the largest median percent difference in aPRs (e.g., between county and block group) when results were aggregated for all quartiles. This was followed by the temporal scale and spatial limit decisions. For benzene, spatial limit resulted in largest median percent difference in aPRs, followed by spatial scale and temporal scale. However, for both pollutants, when evaluating the agreement in aPRs between alternative choices on the direction and significance of the association (i.e., statistically significant increase, decrease, or no risk), the decision of spatial limit resulted in the lowest percent agreement (biggest impact). Temporal limit had the second lowest percent agreement for PM2.5, whereas spatial scale had the second lowest for benzene. Finally, the metric assessing the level of overlap in 95% CIs for the measures of association was inconsequential, suggesting little impact of any exposure assessment decision, and doing little to differentiate between the relative impacts of each decision. That is because, for all exposure-outcome pairs, when comparing alternative choices for each decision, there was 100% overlapping intervals (i.e., no aPRs were statistically significantly different from each other). Lastly, exposure assessment decisions impacted the analytic sample sizes, with some decisions resulting in a three-fold difference in the sample size alone. Mothers of singleton infants exposed to higher levels of ambient PM2.5 were more likely than mothers with lower exposure levels to give birth to an infant with isolated anomalies of the skull and face bones, any rib and sternum anomalies, any skull and face anomalies, any spine anomaly, and other congenital anomalies of lower limb including pelvic girdle. Higher PM2.5 exposure was also associated with an increased risk of non-isolated anomalies of skull and face bones, any skull and face anomalies, and reduction deformities of the upper limb. Exposure to higher levels of benzene was associated with an increased risk of isolated congenital hip dislocation and congenital valgus deformities of feet as well as multiple inverse associations. The findings presented here indicate that measures of association between maternal pollutant exposures (PM2.5 and benzene) and selected birth defect outcomes in offspring are sensitive to exposure assessment decisions, with some decisions more impactful than others. The findings can be used, not only to explain the lack of consistency in results across existing epidemiological studies, but to guide decision-making in future studies. This study also adds to the growing body of epidemiological studies suggesting an association between specific air pollutants and birth defects. In the current political climate, it is important that researchers continue to provide evidence of the detrimental health effects of air pollution in order to circumvent change in current policies established to regulate and reduce pollution emissions.

M.Sc. (Physics) / Please refer to full text to view abstract

La cancérogénicité du benzène à forte dose (CIRC, Groupe 1) a été démontrée sur la base des cas de leucémies observés dans les études épidémiologiques conduites en milieu professionnel chez l’adulte exposé à de fortes doses. Ce polluant est émis en faible concentration dans l’environnement, notamment par le trafic routier et les stations-service. L’objectif est d’étudier le lien entre exposition au benzène à faible dose et risque de leucémie chez l’enfant. L’étude GEOCAP regroupe les cas de leucémies de l’enfant diagnostiqués en France entre 2002 et 2007 issus du Registre National des Hémopathies de l’Enfant, et un échantillon de 30 000 témoins représentatif de la population générale pédiatrique. La longueur de routes à fort trafic a été calculée au voisinage de la résidence de chaque sujet géocodé dans un rayon de 150 m. Les concentrations en benzène et en NO2 ont été estimées pour l’ensemble des sujets de France continentale à une échelle de 2 km2. La distance à la station-service la plus proche a également été calculée depuis la résidence de chaque sujet. La longueur de routes au voisinage de la résidence était positivement et significativement associée au risque de leucémie aigüe myéloblastique (LAM). La prise en compte des expositions au benzène et en NO2 renforçait cette association. La distance à la station-service la plus proche était positivement mais non-significativement associée à la LAM, et cette association résultait en partie d’un effet de confusion de la longueur de routes au voisinage de la résidence. Ce travail soutient l’hypothèse selon laquelle l’exposition au benzène émis dans l’environnement pourrait induire une augmentation du risque de LAM chez l’enfant. / In adults, the relationship between benzene exposure (IARC, Group 1) and leukemia has been demonstrated in workplace for high-level exposure. This pollutant is emitted at low concentration in environment, especially by road traffic and petrol stations. The objective was to investigate the relationship between benzene exposure at low-level dose and childhood leukemia. The record-based GEOCAP study included all cases of childhood leukemia diagnosed in France over 2002-2007 and 30,000 contemporaneous population-based control children highly representative of the source population. The length of major roads was calculated around the residence of each geocoded subject in a 150-m buffer. We assigned them the yearly estimates of benzene and NO2 concentrations at the square where his residence was located on a 2-km2 grid covering continental France. The distance to the nearest petrol station from the residence was also calculated for all subjects. The length of major roads around the residence was positively and significantly associated with the risk of acute myeloblastic leukemia (AML). This association was more evident with benzene and NO2 2-km estimates, combined with the length of major roads indicator to enhance the exposure contrasts. The distance to the nearest petrol station was positively but non-significantely associated with AML, and some of this association was explained by a confouding effect of the length of major roads around the residence. This work suggests that exposure to benzene emitted in environment may increase the risk of AML in children.

The isomer distribution in the sulfonation of iodobenzene at -12.5°C. with sulfur tr~oxide (S-35) in liquid sulfur dioxide was found to be 1.40 ± 0.11% ortho, 0.34 ± 0.11% meta, and 98.26 ± 0.11% para. Pure sodium salts of each of the isomers were made from the corresponding aminobenzenesulfonic acids. After dilution with an aliquot of the sulfonation mixture, the salts were purified by recrystallization and were counted by liquid scintillation counting. Attempts to determine the relative rate of sulfonation between toluene and iodobenzene failed. The radioactive sodium p-iodobenzene sulfonate could not be separated from sodium p-toluenesulfonate by recrystallization. The lithium amides of methylamine, ethylamine, isopropylamine, tert-butylamine and 2-aminopropane-2-d were prepared from phenyl lithium and the amines. Infrared spectra of the amides were scanned in the C-H region. Comparison of the spectra of the amides and the amines showed no shifts like those found for the corresponding alcohol-alkoxide spectra. It was therefore concluded that anionic hyperconjugation could not account for the shift in the spectra of the alcohol-alkoxide system. The behavior of cyclooctatetraene, the silver adduct of cyclooctatetraene, norbornadiene, diphenylacetylene, tetraphenylcyclobutadiene-palladium chloride and ferrocene was studied under high pressures ranging from 15 to 55 kats. and with temperatures from 25 to 850°C. This work was carried out with Hall's tetrahedral anvil apparatus. If the temperature was high enough each of these compounds was found to decompose. When the temperature was below the decomposition temperature, cyclooctatetraene, diphenylacetylene and norbornadiene polymerized. No evidence of a valence tautomerization was found. The silver adduct of cyclooctatetraene and tetraphenylcyclobutadiene-palladium chloride decomposed at high temperatures. No other results were noted with these two compounds. Ferrocene underwent decomposition by iron catalysis to a mixture of iron carbides at pressures from ambient to 55 kats. and temperatures above 500°C. The same products were observed if no iron was added and the temperature and pressure were 55 kats. and 800°C., respectively. A preliminary spectrophotometric study of benzonitrile in 25%-ethyl alcohol-75% water was carried out. Cupric bromide and hydrobromic acid or cupric chloride and hydrochloric acid were added to constant ionic-strength solutions of benzonitrile. No evidence was found in the ultraviolet region for any complex ion formation. The same results were found for p-fluorobenzonitrile.

We have calculated the structures, the heats of hydrogenation and the resonance energies of benzene isomers. All structures and energies were calculated by using the MMX force fields. Using PC model, the calculated structure parameters of benzene's 8 isomers are generally in good agreements with the experimental data. The heats of hydrogenation and resonance energy of benzene isomers are parallel to those experimental data and need a. systematic adjustment of 4.5 kJ/mol.