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Produ??o de biodiesel a partir de ?leos e gorduras residuais utilizando ?cido sulf?rico imobilizado em s?lica como catalisador e aplica??o do glicerol na produ??o de cetal / Biodiesel production from waste cooking oil using sulfuric acid as catalyst immobilized on silica and applied of glycerol in the production of ketalMacedo, Alice Lopes 20 April 2013 (has links)
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Previous issue date: 2013 / Os catalisadores heterog?neos desenvolvidos pelo grupo de pesquisa a base de ?cidos de Lewis suportados em diferentes ?xidos inorg?nicos, como por exemplo o ZnCl2/SiO2 e FeSO4/SiO2, tem se mostrado excelentes na esterifica??o de ?cidos graxos livres, por?m ineficazes quando aplicados na transesterifica??o de ?leos vegetais. Este trabalho prop?e o estudo e a s?ntese de um catalisador produzido a partir da substitui??o dos ?cidos de Lewis por ?cido de Bronsted-Lowry, tais como, o ?cido sulf?rico e o ?cido clor?drico. ?leos e gorduras residuais geralmente cont?m um alto ?ndice de ?cidos graxos livres (AGL) e um elevado teor de ?gua em sua constitui??o. Essas subst?ncias dificultam a a??o dos catalisadores b?sicos como NaOH ou KOH que s?o amplamente empregados nestes processos, levando tamb?m a inibi??o de alguns catalisadores a base de ?cidos minerais. A nova mistura catal?tica (H2SO4/SiO2) foi sintetizada a partir de ?cido sulf?rico 10 M imobilizado em s?lica 24 mesh, previamente preparada a partir de areia de constru??o e carbonato de s?dio e caracterizada pelas seguintes t?cnicas anal?ticas: Microscopia Eletr?nica de Varredura, Espectrometria de Dispers?o de Energia, Infravermelho e Termogravimetria. O catalisador foi inicialmente aplicado com ?xito em rea??es de transesterifica??o de ?leos vegetais refinados e de ?leos e gorduras residuais purificados, por?m o grande desafio foi realizar a transesterifica??o de ?leos vegetais de baixa qualidade, os chamados ?leos e gorduras residuais, que al?m de possu?rem em sua constitui??o ?leos vegetais misturados ? gordura animal e ?cidos graxos livres, s?o muitas vezes contaminados por at? 1% de ?gua, em que propor??es acima de 0,5% m/m podem levar a total desativa??o do catalisador. O emprego de s?lica sint?tica 24 mesh na constitui??o do catalisador objetivou aumentar a ?rea de superf?cie, favorecendo o processo de adsor??o de ?gua oriunda da esterifica??o de ?cidos graxos livres e tamb?m a contida nos ?leos e gorduras residuais, evitando uma maior perda da atividade catal?tica por lixivia??o. O rendimento obtido em biodiesel foi acima de 99%, calculado a partir dos dados obtidos por Cromatografia Gasosa acoplada a Espectr?metro de Massa. O catalisador utilizado no processo foi recuperado por lavagem em ?ter et?lico e ativado em estufa 150? C por 3 horas e utilizado em outros processos reacionais. O glicerol obtido como subproduto da transesterifica??o foi utilizado sem pr?via purifica??o na rea??o de catalisa??o com acetona empregando H2SO4/SiO2, formando o cetal 2,2-dimetil-1,3-dioxolano-4-il metanol em 93% de rendimento, o qual foi determinado por CG/EM. Este produto ? caracterizado por sua grande aplica??o como aditivo para combust?veis pela ind?stria automobil?stica. A mistura catal?tica (H2SO4 10M/SiO2) utilizada possui uma capacidade de carga de 1,91x10-3 mols H+/g, ou aproximadamente 9,4% m/m de H2SO4 no catalisador e equivalente a 0,94% m/m de H2SO4 em rela??o ao ?leo vegetal empregado nos diferentes processos reacionais. Essas propor??es se mostraram bem abaixo das propor??es normalmente empregadas em rea??es de transesterifica??o catalisadas por ?cido sulf?rico, que variam de 4 a 5%. O emprego deste catalisador nos processos de transesterifica??o e de catalisa??o, permitiu a sua recupera??o e reutiliza??o por 2 ciclos, sendo que ap?s o ?ltimo ciclo a s?lica resultante foi acidificada novamente, seca e empregada em novos processos catal?ticos. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2013. / ABSTRACT
The heterogeneous catalysts developed by our research group based Lewis acid supported on various inorganic oxides such as: ZnCl2/SiO2 and FeSO4/SiO2, has proved excellent for esterification of free fatty acids, but ineffective when applied in the transesterification vegetable oils. This paper proposes the synthesis and study of a catalyst produced from the Br?nsted-Lowry acids sulfuric acid in replacement of previously employed Lewis acids. Waste oils and fats generally contain a high content of free fatty acids (FFA), as well as a high water content, these substances hinders the action of basic catalysts such as NaOH or KOH which are widely used in these processes, taking also inhibition of some catalysts from the mineral acids.
The new catalyst mixture (H2SO4/SiO2) was synthesized from 10 M sulfuric acid immobilized on silica 24 mesh, previously prepared from construction sand and sodium carbonate. Later this material was characterized using the following analytical techniques, Scanning Electron Microscopy, Spectroscopy Dispersion Energy, Infrared and thermogravimetric analysis.
Initially, the catalyst was applied in transesterification of vegetable oils and refined oils and waste fats purified. However, the most challenge was to perform the transesterification of vegetable oils of low quality, they called residual oils and fats, over to have in their constution vegetable oils mixed with animal fat and free fatty acid are often contaminated by 1% water, in proportions up to 0.5% w/w can lead to complete deactivation of the catalyst.
The use of synthetic silica 24 mesh aimed to increase the surface area, favoring the adsorption of water from the esterification of free fatty acids and also contained in the waste oils and fats, preventing further loss of catalytic activity by leaching. The yield obtained in biodiesel was above 99%, calculated from the data obtained by GC/MS. The catalyst used in the process was recovered by washing using ethyl ether and activated in an oven 150 ?C for 3 hours and used in the process of ketalization of glycerol, as well as in subsequent transesterification reactions. The glycerol obtained as a byproduct of the transesterification was used without purification in the previous reaction of ketalization with acetone employing H2SO4/SiO2 ketalization with acetone forming the ketal 2,2-dimethyl-1 ,3-dioxolan-4-yl methanol in 93% yield, which was determined by GC/MS. This product is characterized by its wide application as a fuel additive for the automotive industry. The catalytic mixture (H2SO410 M/SiO2) used has a capacity of 1.91 x10-3mol H+/g, or about 9,4% w/w of H2SO4 in the catalyst, equivalent to 0.94% w/w of H2SO4 in compared to vegetable oil employed in the different reaction processes, these proportions were below the proportions normally used in transesterification reactions catalyzed by sulfuric acid ranging from 4 to 5%.
The use of this catalyst in processes of transesterification and ketalization allowed the recovery and reuse during two cycles. After the last cycle, the resulting silica was acidified, dried and used in another catalytic process
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Synthèses d’inhibiteurs sélectifs des endosulfatases humaines H-Sulf 1 et 2 / Synthesis of human endosulfatase H-Sulf 1 and 2 's specifics inhibitorsMock-Joubert, Maxime 09 June 2017 (has links)
Les endosulfatases (H-Sulf 1 et 2) catalysent l’hydrolyse des sulfates en position 6 des résidus glucosamine des chaines d’héparane sulfate. Elles modulent ainsi l’activité des héparanes sulfate vis à vis de nombreuses protéines. Plusieurs études ont montré que l’endosulfatase H-Sulf 2 est produite en quantité plus importante dans de nombreux cancers (poumons, sein, pancréas etc …). La réduction de l’activité de cette enzyme chez des souris malades permet la diminution de la tumeur ainsi que le prolongement de la durée de vie. Ce travail de thèse vise à synthétiser une série d’inhibiteurs spécifiques des endosulfatases humaines. Une étude préliminaire a été menée sur un monosaccharide portant une fonction sulfamate, cette fonction étant connue pour inhiber les sulfatases. Ce projet de thèse repose sur la synthèse d’oligosaccharide de type héparane sulfate de tailles différentes portant tous cette fonction inhibitrice. Pour ce faire il a fallu mettre au point une stratégie itérative incluant des réactions de glycosylations stéréosélectives. Puis l’ouverture régiosélective d’acétal de benzylidène ainsi que la sulfamoylation ont été examinées l’optimisation des fonctionnalisations et des déprotections sont encore en cours afin de compléter cette librairie de molécules inhibitrice des endosulfatases humaines. / Human endosulfatase (H-Sulf 1 and 2) catalyse heparan 6-O-sulfate hydrolysis. Thanks to this hydrolysis they change the heparan sulfate proteoglycan activity. Many studies have shown that H-Sulf 2 are surexpressed in many cancer (lung, breast, pancreas etc...) The decrease of the activity of this enzyme in the case of the mouse allows a decrease of the size of the tumor and an extension of the mouse life. The aim of this thesis is to synthetise a library of endosulfatase specific inhibitors. A preliminary study was made on a monosaccharide carrying a sulfamate. This fonctional group have shown that it is able to inhibate the sulfatases. This project thesis is to synthetise heparan sulfate oligsaccharides carrying this sulfamate moeity. We apply an iterative process to make this oligosaccharide, thanks to a high stereoselective glycosylation. Finaly a reductive opening of benzylidène acetals, a sulfamoylation have been examinated, functionalization and deprotection are still in progress for get the full library.
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Extracellular remodeling enzyme processed heparan sulfate oligosaccharides: method development and characterization using liquid chromatography mass spectrometryHuang, Yu 22 January 2016 (has links)
Glycans and glycoconjugates exert myriad important biological functions, extending and diversifying the functionality of protein molecules. Extensive studies have focused on the protein and gene realms; however, due to the lack of means for external amplification and the inherent heterogeneity of glycans and glycoconjugates, their researches have not adequately informed the understanding of critical biological and pathological processes. Researchers in glycoscience have strived to bridge this gap and redefine our understanding of carbohydrate functions.
Glycosaminoglycans (GAGs) represent the most highly charged and poly-disperse animal glycans. GAGs exist on the surfaces of most mammalian cells and in the extracellular matrices. They play critical roles in anticoagulation, angiogenesis, inflammation, metastasis, cell proliferation and differentiation. Heparin and heparan sulfate (HS) are the most highly sulfated and structurally diverse GAGs, regulating a variety of cell functions by interacting directly with many growth factors and their receptors. Examples include fibroblast growth factor, bone morphogenetic protein and Wnt. These interactions rely on the unique structural properties of HS/heparin molecules. Extracellular enzymes (Sulfs and heparanase) also alter the fine structure of HS molecules. In order to investigate to the correlation between structure and function for mature HS/heparin chains, we employed mass spectrometry (MS) coupled with liquid chromatography (LC) as a sensitive and robust platform for composition profiling and detailed structural characterization. We developed a novel HPLC-chip based LC-MS platform to enable HS oligosaccharide profiling. In this thesis work, the chip LC-MS platform was improved for effective and informative tandem MS for HS oligosaccharides. We also advanced electron-based ion dissociation methods for more detailed and reliable sequence determination of HS oligosaccharides. These newly developed methods enable the investigation of the HS/heparin structural changes induced by HS extracellular remodeling enzymes, human Sulfs and heparanase. Application of the methods revealed the recognition preferences of these remodeling enzymes at the oligosaccharide level and led to the discovery of a novel peeling reaction induced by the 3-O-sulfation at the reducing end of HS saccharides.
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Estudo do desempenho de resinas polim?ricas para remo??o de H2S do g?s naturalSilveira, Valdelice Rodrigues da 11 July 2007 (has links)
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Previous issue date: 2007-07-11 / The natural gas (NG) is a clean energy source and found in the underground of porous rocks, associated or not to oil. Its basic composition includes methane, ethane, propane and other components, like carbon dioxide, nitrogen, hydrogen sulphide and water. H2S is one of the natural pollutants of the natural gas. It is considered critical concerning corrosion. Its presence depends on origin, as well as of the process used in the gas treatment. It can cause problems in the tubing materials and final applications of the NG. The Ag?ncia Nacional do Petr?leo sets out that the maximum concentration of H2S in the natural gas, originally national or imported, commercialized in Brazil must contain 10 -15 mg/cm3. In the Processing Units of Natural Gas, there are used different methods in the removal of H2S, for instance, adsorption towers filled with activated coal, zeolites and sulfatreat (solid, dry, granular and based on iron oxide). In this work, ion exchange resins were used as adsorbing materials. The resins were characterized by thermo gravimetric analysis, infrared spectroscopy and sweeping electronic microscopy. The adsorption tests were performed in a system linked to a gas-powered chromatograph. The present H2S in the exit of this system was monitored by a photometrical detector of pulsing flame. The electronic microscopy analyzes showed that the topography and morphology of the resins favor the adsorption process. Some characteristics were found such as, macro behavior, particles of variable sizes, spherical geometries, without the visualization of any pores in the surface. The infrared specters presented the main frequencies of vibration associated to the functional group of the amines and polymeric matrixes. When the resins are compared with sulfatreat, under the same experimental conditions, they showed a similar performance in retention times and adsorption capacities, making them competitive ones for the desulphurization process of the natural gas / O g?s natural (GN) ? uma fonte de energia limpa encontrada no subsolo de rochas porosas, associado ou n?o ao petr?leo. Sua composi??o b?sica inclui metano, etano, propano e outros componentes, como di?xido de carbono, nitrog?nio, ?cido sulf?drico e ?gua. H2S ? um dos poluentes naturais do g?s natural. ? considerado cr?tico no que se refere ? corros?o. Sua presen?a depende da origem, bem como do processo usado no tratamento do g?s. Ele pode acarretar problemas nas tubula??es e aplica??es finais do GN. A Ag?ncia Nacional de Petr?leo estabelece que a concentra??o m?xima de H2S no g?s natural, de origem nacional ou importado, comercializado no Brasil contenha no m?ximo 10 15 mg/m3. Nas Unidades de Processamento do G?s Natutal, diferentes m?todos s?o usados na remo??o de H2S, por exemplo, em torres de adsor??o recheadas com carv?o ativo, ze?litas e Sulfatreat (s?lido, seco, granular e baseado em ?xido de ferro). Neste trabalho, resinas de troca-i?nica foram usadas como material adsorvente. As resinas foram caracterizadas por an?lise termogravim?trica, espectroscopia de infravermelho e microscopia eletr?nica de varredura. Os ensaios de adsor??o foram realizados em um sistema acoplado a um cromat?grafo a g?s. O H2S presente na sa?da do sistema foi monitorado por um detector fotom?trico de chama pulsante. As an?lises de microscopia eletr?nica demonstraram que a topografia e morfologia das resinas favorecem o processo de adsor??o. Caracter?sticas como comportamento macro, part?culas de tamanhos variados, geometrias esf?ricas, sem a visualiza??o de poros na superf?cie, foram encontrados. Os espectros de infravermelho apresentaram as principais freq??ncias de vibra??o associadas aos grupos funcionais das aminas e matrizes polim?ricas. Quando comparadas ao sulfatreat, sob as mesmas condi??es experimentais, as resinas demonstraram semelhante desempenho em tempos de reten??o e capacidade de adsor??o, tornando-se competitiva para o processo de dessulfuriza??o do g?s natural
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Estudo do desempenho de resinas polim?ricas para remo??o de H2S do g?s naturalSilveira, Valdelice Rodrigues da 11 July 2006 (has links)
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Previous issue date: 2006-07-11 / The natural gas (NG) is a clean energy source and found in the underground of porous rocks, associated or not to oil. Its basic composition includes methane, ethane, propane and other components, like carbon dioxide, nitrogen, hydrogen sulphide and water. H2S is one of the natural pollutants of the natural gas. It is considered critical concerning corrosion. Its presence depends on origin, as well as of the process used in the gas treatment. It can cause problems in the tubing materials and final applications of the NG. The Ag?ncia Nacional do Petr?leo sets out that the maximum concentration of H2S in the natural gas, originally national or imported, commercialized in Brazil must contain 10 -15 mg/cm3. In the Processing Units of Natural Gas, there are used different methods in the removal of H2S, for instance, adsorption towers filled with activated coal, zeolites and sulfatreat (solid, dry, granular and based on iron oxide). In this work, ion exchange resins were used as adsorbing materials. The resins were characterized by thermo gravimetric analysis, infrared spectroscopy and sweeping electronic microscopy. The adsorption tests were performed in a system linked to a gas-powered chromatograph. The present H2S in the exit of this system was monitored by a photometrical detector of pulsing flame. The electronic microscopy analyzes showed that the topography and morphology of the resins favor the adsorption process. Some characteristics were found such as, macro behavior, particles of variable sizes, spherical geometries, without the visualization of any pores in the surface. The infrared specters presented the main frequencies of vibration associated to the functional group of the amines and polymeric matrixes. When the resins are compared with sulfatreat, under the same experimental conditions, they showed a similar performance in retention times and adsorption capacities, making them competitive ones for the desulphurization process of the natural gas / O g?s natural (GN) ? uma fonte de energia limpa encontrada no subsolo de rochas porosas, associado ou n?o ao petr?leo. Sua composi??o b?sica inclui metano, etano, propano e outros componentes, como di?xido de carbono, nitrog?nio, ?cido sulf?drico e ?gua. H2S ? um dos poluentes naturais do g?s natural. ? considerado cr?tico no que se refere ? corros?o. Sua presen?a depende da origem, bem como do processo usado no tratamento do g?s. Ele pode acarretar problemas nas tubula??es e aplica??es finais do GN. A Ag?ncia Nacional de Petr?leo estabelece que a concentra??o m?xima de H2S no g?s natural, de origem nacional ou importado, comercializado no Brasil contenha no m?ximo 10 15 mg/m3. Nas Unidades de Processamento do G?s Natutal, diferentes m?todos s?o usados na remo??o de H2S, por exemplo, em torres de adsor??o recheadas com carv?o ativo, ze?litas e Sulfatreat (s?lido, seco, granular e baseado em ?xido de ferro). Neste trabalho, resinas de troca-i?nica foram usadas como material adsorvente. As resinas foram caracterizadas por an?lise termogravim?trica, espectroscopia de infravermelho e microscopia eletr?nica de varredura. Os ensaios de adsor??o foram realizados em um sistema acoplado a um cromat?grafo a g?s. O H2S presente na sa?da do sistema foi monitorado por um detector fotom?trico de chama pulsante. As an?lises de microscopia eletr?nica demonstraram que a topografia e morfologia das resinas favorecem o processo de adsor??o. Caracter?sticas como comportamento macro, part?culas de tamanhos variados, geometrias esf?ricas, sem a visualiza??o de poros na superf?cie, foram encontrados. Os espectros de infravermelho apresentaram as principais freq??ncias de vibra??o associadas aos grupos funcionais das aminas e matrizes polim?ricas. Quando comparadas ao sulfatreat, sob as mesmas condi??es experimentais, as resinas demonstraram semelhante desempenho em tempos de reten??o e capacidade de adsor??o, tornando-se competitiva para o processo de dessulfuriza??o do g?s natural
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Aplica??o de termogravimetria acoplada ? espectrometria de massas para caracteriza??o de petr?leo e determina??o da curva de evolu??o de g?s sulf?dricoRibeiro, Marcilio Pelicano 12 February 2009 (has links)
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Previous issue date: 2009-02-12 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / With the new discoveries of oil and gas, the exploration of fields in various geological basins, imports of other oils and the development of alternative fuels, more and more research labs have evaluated and characterized new types of petroleum and derivatives. Therefore the investment in new techniques and equipment in the samples analysis to
determine their physical and chemical properties, their composition, possible contaminants, especification of products, among others, have multiplied in last years, so development of techniques for rapid and efficient characterization is extremely important for a better economic recovery of oil. Based on this context, this work has two main objectives. The first one is to characterize the oil by thermogravimetry coupled with mass spectrometry (TG-MS), and correlate these results with from other types of characterizations data previously informed. The second is to use the technique to develop a methodology to obtain the curve of evaluation of hydrogen sulfide gas in oil. Thus, four samples were analyzed by TG-MS, and X-ray fluorescence spectrometry (XRF). TG results can be used to indicate the nature of oil, its tendency in coke formation, temperatures of distillation and cracking, and other features. It was observed in MS evaluations the behavior of oil main compounds with temperature, the points where the volatilized certain fractions and the evaluation gas analysis of sulfide hydrogen that is compared with the evaluation curve obtained by Petrobras with another methodology / Com as novas descobertas de petr?leo e g?s, a explora??o de campos em v?rias bacias geol?gicas, a importa??o de outros ?leos e o desenvolvimento de combust?veis alternativos,
cada vez mais os laborat?rios de pesquisa t?m avaliado e caracterizado novos tipos de petr?leo e derivados. Por conseq??ncia os investimentos em novas t?cnicas e equipamentos de an?lise para determina??o na amostra das suas propriedades f?sico-qu?micas, da sua composi??o, de poss?veis contaminantes, de especifica??o de produtos, entre outros, t?m se multiplicado nos ?ltimos anos, de modo que o desenvolvimento de t?cnicas r?pidas e eficientes de caracteriza??o ? extremamente importante para um melhor aproveitamento econ?mico do petr?leo. Com base neste contexto, este trabalho tem dois objetivos principais.
O primeiro ? caracterizar o petr?leo atrav?s da an?lise termogravim?trica acoplada ? espectrometria de massas (TG-MS), e correlacionar esses resultados com dados de outros
tipos de caracteriza??es previamente informados. O segundo ? utilizar a t?cnica para desenvolver uma metodologia para a obten??o da curva de evolu??o do g?s sulf?drico no
petr?leo. Assim, quatro amostras foram analisadas por TG-MS e por espectrometria de fluoresc?ncia de raios X (FRX). Os resultados obtidos com a termogravimetria podem ser
utilizados para indicar a natureza do petr?leo, sua tend?ncia ? forma??o de coque, temperaturas de destila??o e craqueamento, entre outras caracter?sticas. Nas curvas de
evolu??o obtidas por espectrometria de massas se observam o comportamento dos principais constituintes do petr?leo em fun??o da temperatura, os cortes onde s?o volatilizadas
determinadas fra??es e a gera??o do g?s sulf?drico, que ? comparada com a curva obtida pela Petrobr?s utilizando outra metodologia
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