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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Effect Of Hydrogenation Conditions On Rheological And Micro-structural Properties Of Fats

Baskocak, Altug 01 September 2011 (has links) (PDF)
Hydrogenation is one of the most applied techniques in the fats and oils industry to produce wide range of hardened fats with different physical and chemical properties. Each different combination of hydrogenation conditions serves products of different rheological and micro-structural properties. Therefore, the purpose of this study is to examine the effect of different industrially available catalysts on rheological and micro-structural properties of hydrogenated fats. Three different catalysts were used at two different concentrations to hydrogenate soybean oil. Two nickel based (Nysosel 222 and SP 10) and one palladium based (Pd/Al2O3) catalyst were employed. Each oil sample was hydrogenated for 20, 40, 60, 80 and 100 minutes of time intervals, under 165 &ordm / C temperature, 2 bar H2 pressure and 500 rpm stirring rate. Resulting hardened fat samples were analysed in terms of rheological and microstructural properties. The outcomes of rheological and micro-structural analyses had a strong resemblence with the fatty acid distributions, solid fat contents, slip melting points and iodine values of the samples. The most selective catalyst was SP10, with the products of the highest trans fatty acid concent and more solid-like / where the least selective one was Pd/A with lowest trans fatty acid content and least solid-like. Crystal number and properties, the behaviours of storage and loss moduli were in correlation with trans fatty acid content of the samples. Also the moduli had a considerable parallelity with solid fat contents.
12

Heterogeneous catalysts in aqueous phase reforming environments: an investigation of material stability

Ravenelle, Ryan M. 14 November 2011 (has links)
There are many problems associated with the use of fossil fuels to produce fuels and chemicals, and lignocellulosic biomass stands as a promising alternative fuel/chemical feedstock. Large scale processing of biomass will likely take place in high temperature liquid water due to the low vapor pressure and polar nature of carbohydrates. However, little is known about the material stability of these catalysts in high temperature aqueous phase environments. This dissertation aims to investigate the structural integrity of some common catalytic materials under typical biomass reforming conditions. There are 3 main objectives of this study: 1) identify potentially stable candidates from commonly used materials, 2) understand the mechanism(s) by which these catalysts degrade, 3) design/modify catalysts in an effort to increase their hydrothermal stability. The two main materials investigated in this work are zeolites (faujasite, ZSM-5) and γ-Al2O3 as these are commonly used as catalysts and catalyst supports. A number of physicochemical techniques were used to characterize the materials as a function of treatment time at conditions relevant for biomass reforming. For zeolites, the major findings are that ZSM-5 framework is highly stable whereas faujasite stability depends on the Si/Al ratio, where silicon rich materials are less stable. For γ-Al2O3 based catalysts, it was found that the alumina support hydrates and undergoes a phase transformation to form crystalline boehmite (AlOOH) with a subsequent loss in surface area and Lewis acid sites. When metal particles are present on the support, the phase change kinetics are slowed. The role of metal precursor on the stability of γ-Al2O3 supported catalysts was also explored, and it was found that the precursor used in catalyst synthesis changes the boehmite formation kinetics and also affects alumina support dissolution. The final thrust aims to stabilize a Pt/γ-Al2O3 catalyst by depositing silicon on the catalyst surface. The silicon modification is effective in protecting the catalyst from boehmite formation upon exposure to hot liquid water while also stabilizing metal particles against sintering. Additionally, an increase in turnover number for hydrogen production via aqueous phase reforming of sorbitol was observed.
13

Targeted Synthesis and Characterization of Nanostructured Silicate Building Block Supports and Heterogeneous Catalysts with Tungsten(VI) or Zirconium(IV) Centers

Peretich, Michael Edward 01 December 2011 (has links)
Catalysts play a vital role in almost every aspect of our lives and are used in the production of fuels, polymers, chemicals, foods, and pharmaceuticals. One challenge facing the heterogeneous catalysis community is the targeted synthesis of dispersed catalyst ensembles. The Barnes research group has developed a general methodology for the synthesis of nanostructured silicate building block supports and heterogeneous catalysts. This methodology provides researchers with the ability to control the dispersion of surface functionality, the dispersion of metal cation centers, the number of linkages from the metal cation center to the support, the surface area of the support, and the porosity of the support. This dissertation describes work aimed at synthesizing and characterizing nanostructured silicate building block supports and heterogeneous catalysts. Nanostructured silicate building block supports were synthesized by reacting SiCl4py2 with Si8O12(OSnMe3)8. The resulting supports contained spatially isolated Me3Sn groups and the density of Me3Sn groups was targeted by varying the stoichiometric ratio of reactants. The stoichiometric ratio of reactants also controlled the surface area and porosity of the supports. Nanostructured heterogeneous catalysts with isolated tungsten(VI) or zirconium(IV) centers were synthesized by reacting a limiting amount of a metal chloride with either Si8O12(OSnMe3)8 or a premade silicate building block support. Two types of catalysts ensembles were targeted: embedded and surface. Embedded ensembles were successfully targeted using WOCl4 and ZrCl4 while the reaction between WCl6 and the building block did not result in the preparation of the targeted ensemble. However the resulting ensemble was thoroughly characterized even though the targeted ensemble was not produced. In all three cases a single type of catalyst ensembles was synthesized and a high surface area silicate support was generated around the embedded ensembles without disrupting the ensemble itself. Surface ensembles were successfully targeted using ZrCl4. The reaction between the tungsten chlorides (WOCl4 and WCl6) and the premade support did not result in the preparation of the targeted ensembles however the resulting ensembles were thoroughly characterized.
14

Bimetallic alloy catalysts for green methanol production via CO2 and renewable hydrogen

Li, Molly Meng-Jung January 2018 (has links)
Recently, the increasing level of atmospheric CO<sub>2</sub> has been widely noticed due to its association with global warming, provoking a growth in environmental concerns toward the continued use of fossil fuels. To mitigate the concentration of atmospheric CO<sub>2</sub>, various strategies have been implemented. Among options to turn waste CO<sub>2</sub> into useful fuels and chemicals, carbon capture and utilisation along with renewable hydrogen production as the source materials for methanol production is more preferable. In the 1960s, the highly active and economic Cu/ZnO/Al<sub>2</sub>O<sub>3</sub> catalyst was developed for CO<sub>2</sub> hydrogenation reaction to methanol, since then, metal nanoparticles and nanocomposites have been extensively investigated and applied. Especially, bimetallic catalysts have emerged as an important class of catalysts due to their unique properties and superior catalytic performances compared to their monometallic counterparts. This thesis presents the evolution of the catalyst development for CO<sub>2</sub> hydrogenation to methanol: Firstly, we introduced the CuZn-based catalysts with Zn content increased in the bimetallic CuZn system via a heterojunction synthesis approach. Secondly, we increased the active CuZn sites via introducing ultra-thin layered double hydroxide as the catalyst precursor for methanol production from CO<sub>2</sub> and H<sub>2</sub>. Thirdly, a new class of Rh-In bimetallic catalysts were studied, which shows high methanol yield and selectivity under thermodynamically unfavourable methanol synthesis conditions owing to the strong synergies of Rh-In bimetallic system. Fourthly, for the renewable methanol production from H<sub>2</sub> and CO<sub>2</sub>, the hydrogen source must come from the green production routes. Therefore, an in-depth study of a nanocomposite system, CdS-carbon nanotubes-MoS<sub>2</sub>, for photocatalytic hydrogen production from water has been demonstrated. Finally, the conclusion of this thesis is given and an outlook is presented for the future development in this research area.
15

Síntese da CTA-MCM-41 a partir de trissilicato de sódio e avaliação na transesterificação de ésteres

Barbosa, Juliana Pereira 25 February 2014 (has links)
Made available in DSpace on 2016-06-02T19:56:53Z (GMT). No. of bitstreams: 1 5790.pdf: 8879884 bytes, checksum: 256bcf8b3832d498d50cb0b4fea7cecc (MD5) Previous issue date: 2014-02-25 / Universidade Federal de Sao Carlos / The increasing demand for it in today s world and the problems caused by fossil fuel usage lead to a search for alternative sources that may integrate the world s energy matrix. In this context, because this product is essential to technological, social and environmental development of a country, biofuels like ethanol and biodiesel are strong candidates to minimize the worries about energy availability. Biodiesel is often produced by transesterification reaction using homogeneous catalyst as sodium hydroxide (NaOH) or potassium hydroxide (KOH). However, these materials present issues like the soap formation and need for additional steps in the process to neutralize and purify the product in order to be under specification of Brazilian National Agency of Petroleum, Natural Gas and Biofuels. This fact has stimulated research to find new materials to replace the current route of biofuels production and one promising material is the heterogeneous catalyst. With this motivation, this work presents a new alternative to the synthesis of a solid recently classified as heterogeneous catalyst, the MCM-41, aiming the minimization of costs for its production. The material was synthesized using sodium trisilicate as silica source and it was later tested, without modification, in transesterification reaction between an ester and an alcohol. The results showed catalyst activity and the conversion was around 40%, but its reuse reveals intense loss of activity because of CTA+ cations removal. However, new techniques are under development to guarantee more stability to the catalyst. / A demanda por energia no mundo atual e os problemas que os combustíveis fosseis oca-sionam, tem impulsionado a procura por fontes alternativas de energia que associadas as fontes já utilizadas possam suprir toda a necessidade energetica. Neste contexto, sabendo que esse produto e essencial para o desenvolvimento tecnológico, social e ambiental de um país, os combustíveis líquidos baseados em biomassa sao fortes candidatos a garantir a se¬gurança energetica mundial, o etanol e o biodiesel são exemplos de produtos com potencial para esse fim. O biodiesel e comumente obtido atraves da reação de transesterificação na presença de catalisadores homogêneos como o hidróxido de sodio (NaOH) ou de potassio (KOH). Entretanto o uso desses materiais apresenta problemas como a possibilidade de formação de sabões e a necessidade de etapas adicionais ao processo para neutralizar e purificar o biodiesel deixando-o dentro das especificações estabelecidas pela Agencia Naci¬onal do Petroleo, Gás Natural e Biocombustóveis. Este fato tem estimulado pesquisas no sentido de sugerir materiais que possam substituir o caminho utilizado atualmente, um desses materiais seria o catalisador heterogeneo. Diante deste cenario, o presente trabalho propoe uma rota alternativa para a síntese de um solido recentemente classificado com catalisador heterogeneo, a CTA-MCM-41, visando minimizar os custos de obtenção deste catalisador. O sílido foi sintetizado utilizando como fonte de sílica o trissilicato de sodio e posteriormente testado sem nenhuma modificacao numa reação modelo entre um ester e um alcool e na reação de transesterificação de oleos vegetais. Os resultados mostram que o catalisador apresentou atividade nas duas reacães, atingindo conversões em torno 40% porém o reuso do catalisador revela uma intensa perda de atividade devido a remoçcaão dos cations CTA+. Entretanto novas tecnicas estao sendo desenvolvidas para garantir uma maior estabilidade ao catalisador.
16

CaracterizaÃÃo e aplicaÃÃo de catalisadores heterogÃneos obtidos a partir de fontes naturais à base de Ãxidos bÃsicos para produÃÃo de biodiesel / CHARACTERIZATION AND APPLICATION OF HETEROGENEOUS CATALYSTS OBTAINED FROM NATURAL SOURCES BASED ON BASIC OXIDES FOR BIODIESEL PRODUCTION

Leandro Marques Correia 26 July 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Atualmente nosso planeta està sofrendo diversas mudanÃas ambientais e assim, o cuidado com o meio ambiente cresce a cada dia. O avanÃo tecnolÃgico na Ãrea de produtos biodegradÃveis està surgindo com o intuito de desenvolver prÃticas para minimizar essas mudanÃas. Como fonte energÃtica renovÃvel, atualmente, vem sendo estudado, o Biodiesel, que à biodegradÃvel, nÃo tÃxico e tem uma reduzida emissÃo de gases nocivos em relaÃÃo ao diesel. Com esse intuito o objetivo desse trabalho foi estudar a aplicaÃÃo de catalisadores heterogÃneos obtidos a partir de fontes naturais (dolomita, casca de caranguejo, casca de ovo, e esferas de quitosana com cÃlcio). A atividade catalÃtica dos materiais foi estudada usando a catÃlise heterogÃnea para produÃÃo de biodiesel. Os materiais utilizados apresentam em sua composiÃÃo quÃmica CaMg(CO3)2 ou CaCO3, os quais, quando modificados termicamente a 850 oC/3h e 900 oC/1h e 2h, respectivamente, resultam em um material altamente bÃsico CaO/MgO ou CaO. Eles tÃm algumas vantagens, tais como abundÃncia, baixo custo, estrutura porosa e nÃo à tÃxico. Os materiais naturais e modificados termicamente foram caracterizados atravÃs de anÃlises de basicidade, FRX, TGA, DRX, FTIR, MEV e Ãrea especÃfica por adsorÃÃo de N2. Para o estudo da aplicaÃÃo dos catalisadores citados acima se utilizou como matÃria-prima o Ãleo de girassol refinado. A matÃria-prima foi caracterizada quanto a composiÃÃo quÃmica dos Ãcidos graxos, Ãndice de acidez, Ãndice de saponificaÃÃo, massa especÃfica a 20 oC, viscosidade cinemÃtica a 40 oC e teor de umidade. AtrÃves da utilizaÃÃo de um planejamento experimental 32 para todos os catalisadores heterogÃneos estudados foram realizadas as reaÃÃes de transesterificaÃÃo com alcool metÃlico, variando-se XRM (1:6; 1:9 e 1:12) , XCAT (1, 2 e 3 % em peso em relaÃÃo à massa do Ãleo pesada), mantendo-se fixas as variÃveis temperatura (60 ÂC) e velocidade de agitaÃÃo (1000 rpm).Verificou-se que os catalisadores proporcionaram as seguintes conversÃes em Ãsteres metÃlicos diante das condiÃÃes reacionais otimizadas: esferas de quitosana com cÃlcio (56,12  0,32 % p/p), casca de caranguejo (83,10  0,27 % p/p), dolomita (96,52  0,43 % p/p) e casca de ovo (97,75  0,02 % p/p), ou seja, os catalisadores heterogÃneos estudados se mostraram promissores e viÃveis na reaÃÃo de transesterificaÃÃo para produÃÃo de biodiesel. / Nowadays our planet is suffering several environmental changes and the care with the environment is growing up every day. Technological advances in the biodegradable products field are increasing in order to develop practices to minimize these changes. Biodiesel has been studied as a renewable energy source, which is biodegradable, nontoxic and has a reduced emission of harmful gases compared to diesel. The objective of this work was to study the application of heterogeneous catalysts derived from natural sources (egg shell, crab shell, dolomite and spheres of chitosan with calcium) for the transesterification reaction of vegetable oils to biodiesel production. The catalsty showed in its chemical composition CaMg(CO3)2 and CaCO3, which when thermally modified resulted in a highly basic CaO/MgO or CaO. These materials have some advantages, such as abundance and inexpensive, porous structure and are not toxic. Some characteristics of natural and modified catalysts were obtained by different techniques, such as XRF, TGA, XRD, FTIR, SEM, potenciometric and specific surface area for N2 adsorption. For the transesterification reactions was used the refined sunflower oil study which was characterized its composition of fatty acids, acid value, saponification number, density at 20 ÂC, kinematic viscosity at 40 ÂC and moisture content. Some parameters were evaluated in the transesterification reaction oil:alcohol molar ratio (XRM) and amount catalsty (XCAT) and optimized using an experimental design (32). The reactions were performed varying XRM (1:6, 1:9 and 1:12), XCAT (1, 2 and 3 w.t% by weight relative to the mass of heavy oil) and fixed the temperature (60 ÂC) and stirring speed (1000 rpm). In the optimized conditions the conversions of vegetable oils to methyl esters were: chitosan sphereswith calcium (56.12  0.32 w.t% ), crab shell (83.10  0 27 w.t% ), dolomite (96.52  0.43 w.t% ) and egg shell (97.75  0.02 w.t%). These results showed that the heterogeneous catalysts studied are promising and viable in the transesterification reaction for biodiesel production.
17

Estudo comparativo de catalisadores ácidos para a produção de biodiesel / Comparative study of acid catalysts for biodiesel production

Guilherme Carvalho Tremiliosi 15 October 2009 (has links)
Para que o processo de produção de biodiesel se torne auto-sustentado, ou seja, socialmente, ecologicamente e economicamente viáveis, alguns aspectos químicos ainda precisam ser estudados e aprimorados. Dentre estes, dois são relevantes: alta eficiência no rendimento da reação e o uso de catalisadores de maneira ecologicamente responsável. Para atendê-los é necessário o uso de catalisadores eficientes, robustos, e facilmente manipuláveis com baixo impacto ao meio ambiente. Para atingir tais objetivos, foi estudado o uso de diferentes catalisadores heterogêneos e métodos analíticos para a determinação do rendimento e caracterização dos produtos formados pela reação de esterificação do ácido oléico, principal componente do óleo de soja, utilizando-se o Etanol e um catalisador heterogêneo à base de sílica, o ormosil. A reação de transesterificação do óleo de soja também foi estudada utilizando-se o Etanol e catalisadores ácidos homogêneos e heterogêneos. / For the biodiesel production process to become self-sustaining, namely, sociably, environmentally and economically viable some chemical aspects have to be studied and improved. Among all of its aspects, two of them are relevant: high efficiency on the reaction yield and the use of catalysts in an environmentally responsible way. To attend to these, the use of, robust and easily manipulated with low environmental impact efficient catalysts is necessary. In order to attain to these objectives, the use of different heterogeneous catalysts and analytical methods for the determination of the yield and characterization of the products formed by the esterification reaction of oleic acid, the main component of soy bean oil, using ethanol and a silica based heterogeneous catalyst, the ormosil, was be studied. The transesterification reaction of the soy oil was also studied, making use of ethanol and homogeneous and heterogeneous acid catalysts.
18

Catalyseurs hétérogènes d’estérification pour l’oléo-chimie / Heterogeneous acid catalysts for esterification in oleochemistry

Kuzminska, Maryna 09 March 2015 (has links)
Le but de cette thèse est de développer des catalyseurs hétérogènes utilisés dans l’estérification de l’acide oléique en triméthylpropane afn de produire un bio-lubrifiant : le triméthylolpropane trioléate. Quatre groupes de catalyseurs furent étudiés 1) hétéropolyacides (HPA) immobilisés sur de la silice après dépôt d’oxyde de zirconium; une forte immobilisation des HPA sur la silice fut obtenue avec notamment une bonne résistance au phénomène de lixiviation garantissant une bonne stabilité du catalyseur. 2) silice macroporeuse (Si(HIPE)) fonctionnalisée avec trois différentes phases actives (HPA, SO3H-/PO3H2-, phosphates de zirconium) : ces catalyseurs présentent une morphologie facile à manipuler mais la réaction se trouve être inhibée par emprisonnement des réactifs et des produits dans les pores. 3) nanoparticules magnétiques fonctionnalisées (MNP) : plusieurs approches furent étudiées pour protéger les MNP lors d’une utilisation à bas pH. La surface recouverte ou greffée avec des MNP a été modifiée pour les groupements sulfoniques. Catalyseurs MNP sont non seulement actifs mais aussi facilement récupérables (propriété magnétiques) et donc réutilisables et recyclables. 4) résines échangeuses de cations ; elles ont montré un réel potentiel industriel grâce à une stabilité remarquable et une possibilité de recyclage unique. Pour les résines de type gel, une étape dite de « pre-swelling » a été développée pour augmenter leurs productivités. Ces résines sont sélectives vers la formation des mono- et diesters, tandis que le triester se forme à cause de la présence d’acide oléique résiduel ou la température élevée du système. Cette coopération entre les catalyses homogène et hétérogène permet de paramétrer la réaction industrielle en la démarrant avec la résine échangeuse d’ions à basse température et la terminer à plus haute température pour obtenir le triester. / This project aims at developing heterogeneous catalysts for the esterification of oleic acid (OA) with trimethylolpropane (TMP) to produce an automotive bio-lubricant, namely trimethylolpropane trioleate (TMPTO). Four groups of catalysts were studied: 1) heteropolyacids (HPA) immobilized onto silica through the link of zirconia; 2) functionalized with three different active phases (HPA, SO3H-/PO3H2-, zirconium phosphates) macroporous Si(HIPE); 3) functionalized magnetic nanoparticles (MNP); and 4) cation ion-exchange resins. We developed a method for the strong immobilization of the HPA onto silica and obtained stable-toward-leaching catalysts (first group of catalysts) which can be easily recycled for the further uses. The Si(HIPE)-materials (second group) have convenient shape that makes them easy to operate but they inhibited the reaction due to entrapment of the reagents and the products inside the small pores. The work dedicated to MNP (third group) investigated different approaches to protect MNP for the use at low pH of the reaction of interest. We found that silica coating of MNP as well as organic silane grafting promote the MNP stability. The surface of coated and grafted MNP was modified to the sulfonic moieties. The MNP-catalysts are easily recoverable by magnet, active and recyclable. Concerning the ion-exchange resins (fourth group), they possess unique stability and recyclability showing potential for the industrial applications. For the gel-type resin the so-called “pre-swelling” step was developed to increase the productivity of the resin. We also found that the resins catalyze the formation of mono- and diesters, whereas the final triester is generated thanks to the residual OA or high temperature of the system. This cooperative scenario between heterogeneous and homogeneous catalysis allows designing the industrial reaction starting with ion-exchange resin at lower temperature and completing it at higher temperature to obtain the triester.
19

Chemická reaktivita tenkých vrstev oxidů ceru na kovových podložkách studovaná metodou teorie funkcionálu hustoty / Chemical reactivity of metal-supported ceria thin films: a density functional study

Szabová, Lucie January 2013 (has links)
Title: Chemical reactivity of metal-supported ceria thin films: a density func- tional study Author: Lucie Szabová Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Vladimír Matolín, DrSc., Department of Surface and Plasma Science, FMF, CU Abstract: The present work is a theoretical analysis based on numerical DFT+U simulations investigating the physical and chemical properties of ultrathin ceria films supported by Cu(111). Such materials exhibit high activity towards several important reactions in heterogeneous catalysis such as water-gas shift and CO oxidation, with important applications also for renewable energy technologies such as fuel cells. We provide evidence of the influence of film thickness on the electronic and structural properties as well as on the reactivity of ultrathin ceria films supported by copper. The calculations combined with scanning tunneling microscopy experiments show that one monolayer thin film of ceria on Cu(111) is charged, strained and contains oxygen vacancies due to the limited thickness of the film. The influence of the film thickness on the reactivity of thin ceria films was explored for the case of water adsorption and dissociation. Significant differences were shown for water adsorption and dissociation on one-monolayer ceria compared to thicker films,...
20

Modificação química da argila bentonítica para uso como suporte catalítico para a síntese do biodiesel.

FELIX, Poliana Harlanne Dantas. 08 May 2018 (has links)
Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-05-08T23:54:46Z No. of bitstreams: 1 POLIANA HARLANNE DANTAS FELIX – TESE(PPGEQ) 2015.pdf: 3400618 bytes, checksum: e0c31389002b48c7a27ae5a248a5146a (MD5) / Made available in DSpace on 2018-05-08T23:54:46Z (GMT). No. of bitstreams: 1 POLIANA HARLANNE DANTAS FELIX – TESE(PPGEQ) 2015.pdf: 3400618 bytes, checksum: e0c31389002b48c7a27ae5a248a5146a (MD5) Previous issue date: 2015-12-22 / Capes / A aplicação de catalisador heterogêneo para a síntese de biodiesel tem sido bastante estudada por ser de grande importância devido ao fato da possibilidade de reuso, além de permitir a utilização de diversas fontes lipídicas. As argilas têm, dentre esses uma alta eficiência, como suporte catalítico em virtude da sua capacidade de trocar cátions fixados na superfície assim como entre as lamelas, sem sofrer modificação na estrutura cristalina, com a inserção de óxidos metálicos de diversas espécies nesse tipo de material; surgem então, os novos catalisadores manométricos; logo, este trabalho, teve por finalidade, estudar e avaliar o potencial catalítico da argila Bentonítica sódica na sua forma natural e tratada quimicamente objetivando seu uso na obtenção do biodiesel. Os suportes catalíticos foram obtidos utilizando a argila bentonítica sódica como suporte, por meio de tratamentos químicos (pilarização, ativação ácida, impregnação com óxido de molibidênio). Todas as amostras catalíticas foram caracterizadas por Difração de Raios X (DRX), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva (EDS), Espectroscopia de Energia Dispersiva de Raios X (EDX) e Espectroscopia na Região do Infravermelho por Transformada de Fourier (FTIR). As curvas de difração indicaram a formação de picos característicos da estrutura do suporte e um deslocamento do pico característico, fato este atribuído ao tratamento químico ao qual foi submetido. As microscopias eletrônicas de varredura dos suportes catalíticos apresentaram uma morfologia irregular com deposição de partículas e aglomerados na superfície do material. Por EDX foram verificados os percentuais dos elementos que constituem a maior parte da composição química dos suportes, os quais são típicos de argilominerais montmorilonita e os maiores percentuais são de óxido de silício e de Alumínio, fato também observado pelo EDS. Os espectros das amostras obtidos por FTIR indicaram as bandas vibracionais que compõem as mesmas, como os grupos a Al-O, Si-O-Si, H2O e também o óxido de molibdênio resultado do processo de impregnação por dispersão física. A síntese do biodiesel deu-se pela reação de transesterificação entre o óleo de soja com o etanol na presença dos catalisadores obtidos. Os suportes catalíticos foram avaliados por percentual de conversão do óleo em éster utilizando-se dois sistemas reacionais denominados; (S1 - Reator Batelada com Pressão Autógena e S2 - Reator Parr). Os produtos obtidos nas sínteses foram caracterizados por cromatografia gasosa; identificou-se o maior percentual de conversão em ésteres da amostra acidificada com ácido clorídrico (BSA2) utilizando o sistema S2 com tempo reacional de 1h. Tal comportamento os potencializa como materiais promissores pois além de se mostrarem ativos, apresentaram um custo de produção relativamente mais baixo em referência a outros materiais já conhecidos e amplamente utilizados. / The application of a heterogeneous catalyst to the synthesis of biodiesel has been studied because it is of great importance due to the possibility of reuse, besides allowing the use of several lipid sources. The clays have a high efficiency as catalytic support due to their ability to exchange cations fixed on the surface as well as between the lamellae without modifying the crystalline structure with the insertion of metallic oxides of several species in this type of material ; Then the new gauge catalysts arise; The objective of this work was to study and evaluate the catalytic potential of the sodium bentonite clay in its natural and chemically treated form, with a view to its use in the production of biodiesel. The catalytic supports were obtained using sodium bentonite clay as a support, through chemical treatments (pillarization, acid activation, impregnation with molybdenum oxide). All the catalytic samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Dispersive Energy Spectroscopy (EDS), X-ray Dispersive Energy Spectroscopy (EDX) and Spectroscopy in the Infrared Region Fourier (FTIR). The diffraction curves indicated the formation of characteristic peaks of the support structure and a characteristic peak displacement, a fact attributed to the chemical treatment to which it was submitted. The scanning electron microscopes of the catalytic supports presented an irregular morphology with deposition of particles and agglomerates on the surface of the material. By EDX the percentages of the elements constituting the major part of the chemical composition of the substrates were verified, which are typical of montmorillonite clay and the highest percentages are of silicon oxide and aluminum, a fact also observed by EDS. The spectra of the samples obtained by FTIR indicated the vibrational bands that make up the same, such as the groups Al-O, Si-O-Si, H2O and also the molybdenum oxide resulting from the process of impregnation by physical dispersion. The synthesis of biodiesel was due to the reaction of transesterification between soybean oil and ethanol in the presence of the catalysts obtained. The catalytic supports were evaluated by percentage conversion of the oil into the ester using two reactive systems denominated; (S1 - Batch reactor with autogenous pressure and S2 - Parr reactor). The products obtained in the syntheses were characterized by gas chromatography; The highest percentage of conversion to esters of the sample acidified with hydrochloric acid (BSA2) was identified using the S2 system with a reaction time of 1h. Such behavior potentiates them as promising materials because in addition to being active, they presented a relatively lower cost of production in reference to other materials already known and widely used.

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