Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-19T13:34:46Z No. of bitstreams: 5 edu.pdf: 1793374 bytes, checksum: 659bf4622f25b099b1d7c3bd613d8f8a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-20T11:06:41Z (GMT) No. of bitstreams: 5 edu.pdf: 1793374 bytes, checksum: 659bf4622f25b099b1d7c3bd613d8f8a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) / Made available in DSpace on 2015-02-20T11:06:41Z (GMT). No. of bitstreams: 5 edu.pdf: 1793374 bytes, checksum: 659bf4622f25b099b1d7c3bd613d8f8a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) Previous issue date: 2013-02-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Neste trabalho est? descrito uma nova metodologia para a produ??o de biodiesel (?steres met?licos ou et?licos de ?cidos graxos) a partir do emprego de diversos ?leos vegetais na sua forma ?bruta?, assim como ?leos residuais oriundos de processo de fritura e tamb?m gordura animal (sebo) como material de partida. Al?m deste desafio, procurou-se realizar as rea??es de transesterifica??es em um processo acelerado por irradia??o das micro-ondas obtidas a partir de um forno de micro-ondas dom?stico, o qual n?o sofreu adapta??es, tais como: inser??o de um sistema de agita??o e tamb?m de refluxo, para ser utilizado em rea??es qu?micas. O primeiro passo do trabalho incluiu a utiliza??o dos diferentes ?leos vegetais brutos, isto ?, desprovidos de processo de refino e de degomagem, para a produ??o de biodiesel. Para tanto foi necess?rio o desenvolvimento de uma metodologia que permitisse a purifica??o desses ?leos vegetais brutos, pois estes podem conter subst?ncias, como a ?gua, os ?cidos graxos livres (AGL) e os ?steres de f?sforos (fosfat?dicos) que s?o inibidoras do processo de transesterifica??o. Na busca por uma t?cnica que permitisse a pr?via purifica??o desses ?leos vegetais, foram testados e obtidos excelentes resultados, quando foi realizada a sua filtra??o em s?lica gel 60 Mesh. A polaridade dessa s?lica oriunda dos grupos silan?is permitiu com grande ?xito a reten??o de AGL e dos ?steres de f?sforo, al?m do seu alto poder de adsor??o, reduzindo de maneira significativa o teor de ?gua presente nesses ?leos vegetais. O fator limitante para o emprego da s?lica gel comercial nos processos de purifica??o das diversas oleaginosas foi o seu alto custo, o que tornava invi?vel o processo de purifica??o. Ap?s diversos estudos e tentativas de encontrar um processo que substitu?sse a s?lica gel comercial anteriormente empregada, foi realizado a s?ntese de uma nova s?lica gel a partir do emprego de areia de constru??o e de carbonatos, sendo um processo simples e de baixo custo. Os resultados obtidos no processo de purifica??o dos ?leos vegetais brutos empregando s?lica gel ?sint?tica? foram similares aos da s?lica gel ?comercial?, o que levou o emprego desse processo de purifica??o de maneira sistem?tica no preparo de mat?ria-prima (reagentes) para posterior transesterifica??o. Os bons resultados permitiram testes dessa nova metodologia de purifica??o em ?leos e gorduras residuais (OGR) oriundos de processos de fritura. Nesses ?leos foram encontrados um n?mero bem maior de subprodutos (impurezas) que podem inibiriooooooo65t\azs NM de maneira parcial ou total o processo de transesterifica??o. Dessa forma, a purifica??o dos OGR tornou-se um grande desafio para a s?lica gel ?sint?tica?. Entre as impurezas contidas nesses ?leos residuais, podemos destacar os AGL, ?gua e os produtos oriundos da degrada??o oxidativa e t?rmica (per?xidos, alde?dos, cetonas, furanos, mon?meros c?clicos e n?o c?clicos) dos ?leos vegetais. Os OGR foram purificados com excelentes resultados por filtra??o sob s?lica gel ?sint?tica? em um processo realizado a temperatura ambiente. Al?m dos ?leos residuais puros, nesse processo foi obtida a gordura animal, a qual ficou retida sobre a s?lica sint?tica dentro do funil de filtra??o. Essa gordura animal foi posteriormente purificada por filtra??o a 60 ?C tamb?m em s?lica gel sint?tica e assim como o ?leo residual utilizada como material de partida na s?ntese de biodiesel. Vale ressaltar que os bons resultados alcan?ados no processo de purifica??o sob s?lica gel sint?tica e a necessidade crescente de mat?ria-prima (?leos vegetais), incentivou a amplia??o do programa de coleta de ?leo e gorduras residuais (OGR) na cidade de Diamantina/MG, intitulado como ?Doe Energia? e implantado em 2006. Tanto os ?leos vegetais brutos, como os ?leos residuais e a gordura animal purificados em s?lica gel sint?tica foram transesterificados a biodiesel (met?lico ou et?lico) em alcoolatos (metanolatos e etanolatos) previamente preparados ?in situ? a partir da solubiliza??o de NaOH ou KOH em metanol ou etanol. Neste processo ocorreu a adi??o do alcoolato sobre o material de partida, sendo a rea??o conduzida sob irradia??o de micro-ondas dom?stica a 240 W durante dez minutos e acompanhada por cromatografia em camada delgada (CCD). Os produtos da rea??o (biodiesel e glicerina) foram separados por decanta??o em funil de separa??o, sendo o biodiesel (et?lico ou met?lico) posteriormente lavado at? pH neutro, seco em Na2SO4 e purificados por destila??o a press?o reduzida. A caracteriza??o do biodiesel produzido foi realizada por m?todos espectrom?tricos como a RMN1H e 13C, al?m disso, o controle de qualidade do biodiesel produzido foi realizado empregando t?cnicas anal?ticas seguindo as normas preconizadas pela Ag?ncia Nacional de Petr?leo, G?s Natural e Biocombust?veis (ANP). A glicerina foi purificada, atrav?s de um pr?vio tratamento com adi??o de ?cido sulf?rico ou clor?drico, gerando o AGL, biodiesel e sulfatos ou cloretos de metais alcalinos como co-produtos. Alguns desses sais como o sulfato de s?dio foi posteriormente purificados por recristaliza??o e utilizados como dessecantes para o pr?prio biodiesel. A efici?ncia da metodologia empregando irradia??o de micro-ondas dom?stica, levou ao estudo do seu uso em rea??es in situ, ou seja, transesterifica??o direta das sementes e dos frutos de oleaginosas, tais como a soja e a mamona. Esse processo consiste em uma desidrata??o pr?via dos frutos ou sementes a uma temperatura de 80 ?C durante 8 horas. O alcoolato preparado foi adicionado sobre os frutos ou sementes triturados e secos e a mistura foi agitada com o aux?lio de um agitador mec?nico a 7500 rpm durante 10 minutos a temperatura ambiente, a fim de homogeneizar a mistura reacional. Essa mistura foi levada a um forno de micro-ondas dom?stico e irradiada a 240 W durante 10 minutos em um processo acompanhado por CCD. Ap?s esse per?odo a massa reacional foi filtrada sob v?cuo, a fim de eliminar o res?duo vegetal s?lido (torta). A solu??o resultante foi transferida para um funil de separa??o, onde ocorreu ap?s poucos minutos, a separa??o do biodiesel (fase superior) da glicerina (fase inferior) por simples decanta??o. Os produtos foram separados por decanta??o e tanto a glicerina como o biodiesel (et?lico ou met?lico) foram purificados e caracterizados. O rendimento em biodiesel foi de aproximadamente 96% no emprego de sementes de soja e de 97% empregando sementes de mamona. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011. / ABSTRACT This work described a new methodology for the production of biodiesel (methyl or ethyl esters of fatty acids) from the use of various vegetable oils in its "raw" as well as waste oil from the frying process and also animal fat (tallow) as starting material. In addition to this challenge, we tried to carry out the reactions transesterification in a process accelerated by microwave irradiation obtained from a domestic microwave oven, which has not undergone changes, such as insertion of an agitation system and also reflux for used in chemical reactions. The first step of the work included the use of different crude oils, this is, devoid of the process of refining and degumming, for the production of biodiesel. For this purpose it was necessary to develop a methodology that allows the purification of crude vegetable oils, as they may contain different substances such as water, free fatty acids (FFA) and esters of phosphorus (Phosphatidic) which are inhibitors of the transesterification process. In the search for a technique that allowed the prior purification of vegetable oils have been tested and achieved excellent results when your filtration was performed on silica gel 60 Mesh. The polarity of this coming from the silica silanol groups with great success allowed the retention of FFA and phosphorus esters, in addition to its high adsorption, significantly reducing the water content present in these oils. The limiting factor for the commercial use of silica gel in the purification processes of other crops was the high cost, which made impossible the purification process. After several studies and attempts to find a process to replace the previously used commercial silica gel was carried out the synthesis of a new silica gel from the use of construction sand and carbonates, with a simple and low cost. The results obtained in the purification process of crude vegetable oils using silica gel "synthetic" were similar to those of silica gel "commercial", which led to the use of this purification process in a systematic manner in the preparation of raw materials (reagents) for subsequent transesterification. The good results allowed testing of this new method of purification of waste oils and fats (WOF) from the frying process. These oils have been found a much larger number of products (impurities) in a manner that can inhibit the partial or total transesterification process. Thus, the purification of WOF has become a major challenge for the silica gel "synthetic". Among the residual impurities contained in these oils, we can highlight the FFA, water and products from thermal and oxidative degradation (peroxides, aldehydes, ketones, furans, cyclic and non cyclic monomers) of vegetable oils. The WOF with excellent results were purified by filtration on silica gel "synthetic" in a process performed at room temperature. Besides the pure residual oils, this process was obtained animal fat, which was held on the synthetic silica into the filter funnel. This fat was then purified by filtration at 60 ?C also on silica gel and synthetic as well as the residual oil is also used as starting material in the synthesis of biodiesel. It is noteworthy that the good results achieved in the purification process in synthetic silica gel and the increasing need of raw material (vegetable oils) has encouraged the expansion of the program to collect waste oil and fats (WOF) in the Diamantina / MG city, titled as "Energy Donate" and implemented in 2006. Both crude vegetable oils, such as waste oils and animal fat purified on silica gel synthesis was transesterified biodiesel (methyl or ethyl) in alcoholates (metanolatos and ethanolate) previously prepared "in situ" from the solubilization of NaOH or KOH in methanol or ethanol. This process was the addition of alcoholates on the starting material, and the reaction was conducted under microwave irradiation of a 240 W home for ten minutes and accompanied by thin layer chromatography (TLC). The reaction products (biodiesel and glycerol) were separated by decanting funnel separation, and biodiesel (methyl or ethyl) subsequently washed until neutral, dried on Na2SO4 and purified by distillation at reduced pressure. The characterization of the biodiesel produced was performed by spectrometric methods such as RMN 1H and 13C, in addition, the quality control of biodiesel was carried out using analytical techniques following the standards recommended by the National Petroleum, Natural Gas and Biofuels Agency (ANP). The glycerin was purified through a previous treatment with sulfuric acid or hydrochloric acid, generating the FFA, biodiesel or chlorides and sulfates of alkali metals as co-product. Some of these salts such as sodium sulfate was further purified by recrystallization and used as desiccants for their own biodiesel. The efficiency of the methodology using a household microwave irradiation, led to the study of their use in reactions in situ, that is, direct transesterification of seeds and fruits of oilseeds such as soybeans and castor beans. This process consists of a prior dehydration of fruits or seeds at a temperature of 80 ?C for 8 hours. The alcoholates prepared was added on the fruits or seeds crushed and dried mixture was stirred with the aid of a mechanical stirrer at 7500 rpm for 10 minutes at room temperature in order to homogenize the reaction mixture. This mixture was brought to a domestic microwave oven and irradiated at 240 W for 10 minutes in a process monitored by TLC. After this time the reaction mass was filtered under vacuum to remove the solid waste plant (cake). The resulting solution was transferred to a separatory funnel, which occurred a few minutes, after the separation of biodiesel (upper phase) of glycerin (lower phase) by simple decantation. The products were separated by decantation and glycerin as much biodiesel (methyl or ethyl) have been purified and characterized. The yield of biodiesel was approximately 96% in the use of soybean and 97% employing castor beans.

Made available in DSpace on 2014-12-17T14:09:14Z (GMT). No. of bitstreams: 1 LuisFL_TESE.pdf: 1981587 bytes, checksum: 1da0819bc859b1e23958de0190156279 (MD5) Previous issue date: 2012-04-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this work, biodiesel was produced from castor oil that was a byproduct glycerin. The molar ratio between oil and alcohol, as well as the use of (KOH) catalyst to provide the chemical reaction is based on literature. The best results were obtained using 1 mol of castor oil (260g) to 3 moles of methyl alcohol (138g), using 1.0% KOH as catalyst at a temperature of 260 ? C and shaken at 120 rpm. The oil used was commercially available, the process involves the reaction of transesterification of a vegetable oil with methyl alcohol. The product of this reaction is an ester, biodiesel being the main product and the glycerin by-product which has undergone treatment for use as raw material for the production of allyl alcohol. The great advantage of the use of glycerin to obtain allyl alcohol is that its use eliminates the large amount of waste of the biodiesel and various forms of insult to the environment. The reactions for the formation of allyl alcohol was conducted from formic acid and glycerin in a ratio 1/1, at a temperature of 260oC in a heater blanket, being sprayed by a spiral condenser for a period of 2 hours and the product obtained contains mostly the allylic alcohol .. The monitoring of reactions was performed by UV-Visible Spectrophotometer: FTIR Fourier transform, the analysis showed that these changes occur spectrometer indicating the formation of the product allylic alcohol (prop-2-en-1-ol) in the presence of water, This alcohol was appointed Alcohol GL. The absorption bands confirms that the reaction was observed in (? C = C) 1470 -1600 cm -1 and (? CO), 3610-3670 attributed to C = C groups and OH respectively. The thermal analysis was carried out in a thermogravimetric analyzer SDT Q600, where the mass and temperature are displayed against time, that allows checking the approximate rate of heating. The innovative methodology developed in the laboratory (LABTAM, UFRN), was able to treat the glycerine produced by transesterification of castor oil and used as raw material for production of allyl alcohol, with a yield of 80%, of alcohol, the same is of great importance in the manufacture of polymers, pharmaceuticals, organic compounds, herbicides, pesticides and other chemicals / Neste trabalho o biodiesel foi produzido a partir de ?leo de mamona que teve como subproduto a glicerina. A raz?o molar entre ?leo e ?lcool, bem como o uso do (KOH) como catalisador qu?mico para proporcionar a rea??o, foi baseada em dados da literatura. Os melhores resultados foram obtidos, utilizando 1 mol de ?leo de mamona (260g) para 3 mols de ?lcool met?lico (138g). O ?leo utilizado foi adquirido comercialmente, o processo de transesterifica??o envolve a rea??o do ?leo vegetal com um ?lcool met?lico. O produto dessa rea??o ? um ?ster, sendo o biodiesel o seu principal produto e a glicerina o sub-produto a qual foi submetida a tratamento para uso como mat?ria-prima para a obten??o do ?lcool al?lico. A grande vantagem do uso da glicerina para obten??o de ?lcool al?lico ? que sua utiliza??o elimina a grande quantidade de res?duos do biodiesel e v?rias formas de agress?o ao meio ambiente. As rea??es para forma??o do ?lcool alilico foram conduzidas a partir de ?cido f?rmico e glicerina, em uma raz?o 1/1, sob temperatura de 260oC, em uma manta aquecedora, sendo vaporizado por um condensador em espiral por um per?odo de 2 horas, e o produto obtido contem em sua grande maioria o ?lcool al?lico. O acompanhamento das rea??es foi realizado por Espectrofot?metro UV-Vis?vel: FTIR com transformada de Fourier, a an?lise revelou que estas altera??es espectrom?tricas ocorrem indicando a forma??o do produto ?lcool al?lico (prop-2-en-1-ol), em presen?a de ?gua, este ?lcool foi nomeado de ?lcool GL. As bandas de absor??o que confirmam a rea??o foram observadas em (? C=C) em 1470 -1600 cm-1 e em (? C-O), 3610 3670 atribu?das aos grupos C=C e O-H respectivamente. A analise t?rmica foi realizada em um analisador Termogravim?trico SDT Q600, onde a massa e a temperatura ser?o exibidos em fun??o do tempo, isto permite a verifica??o aproximada da taxa de aquecimento. A metodologia inovadora desenvolvida no laborat?rio (LABTAM, UFRN), foi capaz de tratar a glicerina produzida, atrav?s da transesterifica??o de ?leo de mamona e utilizar como mat?ria prima para produ??o do ?lcool al?lico, apresentando um rendimento de 80%, deste ?lcool, o mesmo ? de grande import?ncia na fabrica??o de pol?meros, medicamentos, compostos org?nicos, herbicidas, pesticidas e outros produtos qu?micos

Made available in DSpace on 2014-12-17T15:01:18Z (GMT). No. of bitstreams: 1 RicardoHRC.pdf: 2184332 bytes, checksum: 733eb5ecd4a020c789e1bdb3062d808d (MD5) Previous issue date: 2009-03-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The increasing demand for energy and the environment consequences derived from the use of fossil energy, beyond the future scarcity of the oil that currently is the main power plant of the world, it stimulated the research around the production of biodiesel. In this work the synthesis of biodiesel of cotton in the methyl route was carried through, for had been in such a way used catalyst commercial homogeneous, Na-Methylat and the K-Methylat, aiming to the evaluation of the efficiency of them. An experimental planning 23 was elaborated aiming to evaluate the influence of the variable (molar reason oil/alcohol, % of catalyst and temperature) in the process as well as indicating the excellent point of operation in each case. The biodiesel was analyzed by gaseous chromatography, indicating a conversion of 96,79% when used Na-Methylat? as catalytic, and 95,65% when the K-Methylat? was used. Optimum result found with regard to the conversion was obtained at the following conditions: molar reason oil/alcohol (1:8), temperature of 40?C and 1% of catalyst Na-Methylat, reaching a 96,79% conversion, being, therefore, above of the established for the European norm (96.5%). The analysis of regression showed that the only significant effect for a confidence level of 95%, was of the changeable temperature. The variance analysis evidenced that the considered model is fitted quite to the experimental response, being statistically significant; however it does not serve inside for make forecasts of the intervals established for each variable. The best samples were analyzed by infra-red (IR) that identified the strong bands of axial deformation C=O of methylic ester, characterized through analyses physicochemical that had indicated conformity with the norms of the ANP, that with the thermal and rheological analyses had together evidenced that biodiesel can be used as combustible alternative in substitution to diesel / A crescente demanda por energia e as conseq??ncias ambientais derivadas do uso de energia f?ssil, al?m da futura escassez do petr?leo, que atualmente ? a principal fonte de energia do mundo, impulsionaram as pesquisas em torno da produ??o de biodiesel. Neste trabalho foi realizada a s?ntese do biodiesel de algod?o pela rota met?lica, fazendo-se uso de catalisadores comerciais homog?neos, Na-Methylat? e K-Methylat?, visando ? avalia??o da efici?ncia destes. Um planejamento experimental 23 com ponto central em triplicata foi elaborado visando avaliar a influ?ncia das vari?veis (raz?o molar ?leo/?lcool, % de catalisador e temperatura), bem como indicar o ponto ?timo de opera??o em cada caso. Os biodieseis foram analisados por cromatografia gasosa, indicando uma convers?o de 96,79% quando utilizado o Na-Methylat? como catalisador, e 95,65% quando se utilizou o K-Methylat?. O melhor resultado encontrado com rela??o ? convers?o se deu nas seguintes condi??es: raz?o molar ?leo/?lcool (1:8), temperatura de 40?C e 1% de catalisador Na-Methylat, alcan?ando uma convers?o de 96,79%, estando, portanto, acima do estabelecido pela norma europ?ia (96,5%). A an?lise de regress?o submetida mostrou que o ?nico efeito significativo para um n?vel de 95% de confian?a, foi o da vari?vel temperatura. A an?lise de vari?ncia constatou que o modelo proposto se mostra muito bem ajustado ?s respostas experimentais, sendo significativo sob o ponto de vista estat?stico, por?m n?o serve para fins preditivos dentro dos intervalos estabelecidos para cada vari?vel. As melhores amostras foram analisadas por infravermelho que identificou as bandas fortes de deforma??o axial C=O do ?ster met?lico, caracterizadas atrav?s de an?lises f?sico-qu?micas que indicaram conformidade com as normas da ANP, que juntamente com as an?lises t?rmicas e reol?gicas constataram que o biodiesel pode ser utilizado como combust?vel alternativo em substitui??o ao diesel

Data de aprova??o retirada da vers?o impressa do trabalho. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-08-30T18:13:36Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) gelson_cerqueira_oliveira_junior.pdf: 2578577 bytes, checksum: 83cb8ab9378ea856fed151a0f1c1992d (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-08-30T18:51:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) gelson_cerqueira_oliveira_junior.pdf: 2578577 bytes, checksum: 83cb8ab9378ea856fed151a0f1c1992d (MD5) / Made available in DSpace on 2017-08-30T18:51:12Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) gelson_cerqueira_oliveira_junior.pdf: 2578577 bytes, checksum: 83cb8ab9378ea856fed151a0f1c1992d (MD5) Previous issue date: 2015 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Neste trabalho s?lica gel foi preparada a partir de areia de constru??o e carbonato de s?dio, apresentando uma ?rea de superf?cie de 378,68 m2/g, e volume de poro de 1,59x10-2 cm3/g. A fim de preparar diferentes catalisadores a base do mesmo material uma al?quota foi previamente aquecida a 400? C e outra a 700? C, as quais foram denominadas S400 e S700 que ap?s tratamento com H2SO4, deram origem a dois diferentes catalisadores, chamados de C400 e C700. Os catalisadores apresentaram volume total dos mesoporos de 0,23 cm3/g (C400) e 0,20 cm3/g (C700) e ?rea superficial de 31,06 m2/g (C400) e 23,10 m2/g (C700). Pela primeira vez foi utilizado ?cido de Bronsted imobilizado em s?lica para a convers?o de OGR em biodiesel. Ambos C400 e C700 apresentaram alta atividade na convers?o do ?leo e gordura residuais altamente ?cidos (13,7 mg de KOH) e com teor de ?gua de 0,58%, a biodiesel (?steres met?licos de ?cido graxo) em aproximadamente 99,4 %. As rea??es foram repetidas 4 vezes antes do catalisador perder sua atividade catal?tica. / Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Biocombust?veis, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2015. / In this work, silica gel was prepared from building sand and sodium carbonate, having a surface area of 378.68 m2/g and pore volume of 1,59x10-2 cm3/g. In order to prepare different catalysts the basis of the same material aliquot was preheated to 400? C and another at 700? C, which were referred to as S400 and S700 which upon treatment with H2SO4, gave rise to two different catalysts, called C400 and C700. The catalysts showed total volume of mesopores of 0.23 cm3/g (C400) and 0.20 cm3/g (C700) and surface area of 31.06 m2/g (C400) and 23.10 m2/g (C700). For the first time was used Bronsted acid immobilized on silica OGR for conversion into biodiesel. Both C400 and C700 showed high activity in the oil conversion and highly acidic waste fat (13.7 mg of KOH) and 0.58% water content, biodiesel (fatty acid methyl esters) by approximately 99.4% . Reactions were repeated four times before the catalyst to lose its catalytic activity.