Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-06-05T18:19:01Z No. of bitstreams: 2 maisa_costa_santos.pdf: 2334209 bytes, checksum: 9004aeaeb9cd7b271794191d109efa36 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-06-22T12:32:04Z (GMT) No. of bitstreams: 2 maisa_costa_santos.pdf: 2334209 bytes, checksum: 9004aeaeb9cd7b271794191d109efa36 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-06-22T12:32:04Z (GMT). No. of bitstreams: 2 maisa_costa_santos.pdf: 2334209 bytes, checksum: 9004aeaeb9cd7b271794191d109efa36 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016 / Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG) / O presente estudo descreve a s?ntese do catalisador heterog?neo SiO2-SO3H, obtido atrav?s da imobiliza??o dos grupos sulf?nicos em SiO2, produzida a partir de uma mistura contendo ?rea de constru??o e carbonato. A imobiliza??o do -SO3H foi confirmada, atrav?s da caracteriza??o inicial da s?lica e do catalisador por IV, MEV, DRX, TGA e isotermas de adsor??o/dessor??o BET, que demonstrou haver modifica??o da estrutura da s?lica ap?s a imobiliza??o dos grupos sulf?nicos, ocasionando diminui??o da ?rea superficial espec?fica (SBET) de 507 para 115 m2 g?1, e uma diminui??o do volume dos poros 0,78 para 0,38 cm3 g-1. Inicialmente, avaliou o desempenho catal?tico da mistura SiO2-SO3H em rea??es de esterifica??o do ?cido ac?tico e do ?cido graxo (octan?ico) com o 2,2-dimetil-1,3-dioxolano-4-metanol, conhecido como ?solketal?, que possui uma cadeia carb?nica grande, al?m de ter outro grupo funcional na sua estrutura. Os resultados obtidos demonstram a efici?ncia do SiO2-SO3H para a s?ntese do acetato 2,2- dimetil-1,3-dioxolan-4-il metil, em que utilizou-se inicialmente, como reagentes, glicerol bruto, acetona e a mistura catal?tica, ap?s 2 hora de rea??o, foi adicionado no mesmo reator, o ?cido ac?tico em um processo ?one pot?, sem a pr?via extra??o e a purifica??o do solketal (reagente intermedi?rio). Pelo o mesmo procedimento, foi obtido, em excelente rendimento, o octanoato de solketila. Nesses processos reacionais n?o houvera a necessidade do uso de solvente ou aparelhos auxiliares, como clevenger ou dean-stark, para remo??o da ?gua formada durante o processo que envolve 2 rea??es (cetaliza??o e esterifica??o), sendo dessa forma resistente ao processo de lixivia??o. Diante dos excelentes resultados, partiu para rea??es de esterifica??o com outros ?cidos graxos, com at? 18 ?tomos de carbono na cadeia, tais como o ?cido linoleico e oleico. Contudo n?o foi observado a forma??o de produtos nessas rea??es. Acredita-se que esse fato esteja relacionado com a grande afinidade que o solketal apresenta pelo SiO2-SO3H, devido a sua alta polaridade, fazendo com que fique retido dentro dos poros do catalisador. Outro ponto importante foi o tamanho da cadeia carb?nica dos ?cidos graxos utilizados, visto que quanto maior o tamanho da mol?cula, maior a hidrofobicidade, isso faz com que eles sofram repuls?o do catalisador. Acredita-se que esses dois fatores contribu?ram para que n?o ocorresse a intera??o entre os reagentes e o catalisador, levando, em alguns casos, ? forma??o de ?steres de solketila com rendimentos moderados. Essa hip?tese foi comprovada, quando utilizou-se um ?lcool de cadeia carb?nica menor, como o metanol, o qual reagiu com o ?cido linoleico e oleico na presen?a da mistura catal?tica SiO2-SO3H, para produ??o de ?steres met?licos. Os resultados obtidos comprovam a s?ntese do oleato de metila e do linoleato de metila no tempo de 15 min, com rendimento em torno de 96 a 98%. Isso demonstrou que ? de fundamental import?ncia o escoamento dos reagente para os poros do catalisador. O que sugere que para garantir o sucesso das rea??es do solketal com ?cidos de cadeia carb?nica maior o escoamento desse reagentes devem ser facilitado e isso pode ser obtido atrav?s do uso de solvente. / Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Biocombust?veis, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The synthesis of the heterogeneous SiO2-SO3H, catalyst, obtained by the immobilization of the sulfonic groups in SiO2, produced from a mixture containing building and carbonate. The immobilization of -SO3H was confirmed, through the initial characterization of the silica and the catalyst by IV, SEM, XRD, TGA and adsorption / desorption isotherms, which showed that there was modification of the silica structure after the immobilization of the sulfonic groups, resulting in a decrease of the specific surface area (SBET) from 507 to 115 m2 g-1, and decreasing in volume by 0,78 to 0,38 cm3 g-1. Initially, evaluated the catalytic performance of the SiO2 -SO3H mixture in esterification reactions of acetic acid and fatty acid (octanoic acid) with 2,2-dimethyl-1,3-dioxolane-4-methanol, known as "solketal", it has a large carbon chain, plus another functional group in its structure. The results obtained demonstrate the efficiency of SiO2 -SO3H for the synthesis of 2,2-dimethyl-1,3-dioxolan-4-yl methyl acetate, at where initially used as reagents, crude glycerol, acetone and the catalytic mixture, after 2 hour of reaction, was added in the same reactor, acetic acid in a "one pot", without prior extraction and purification of the solketal (intermediate reagent). By the same procedure, it was obtained, in excellent yield, solketila octanoate. In these reaction processes there was no need for the use of solvents or auxiliary devices, such as clevenger or dean-stark, for the removal of water formed during the process involving 2 reactions (ketalization and esterification), thus being resistant to the leaching process. Given the excellent results, started to esterification reactions with other fatty acids, with up to 18 carbon atoms in the chain, such as linoleic and oleic acid. However, the formation of products in these reactions was not observed. It is believed that this fact is related to the great affinity that the solketal presents by the SiO2-SO3H, due to its high polarity, causing it to be trapped within the catalyst pores. Another important point was the size of the carbonic chain of the fatty acids used, since the larger the size of the molecule, the greater the hydrophobicity, this causes them to undergo catalyst repulsion. It is believed that these two factors contributed to the lack of interaction between the reactants and the catalyst, leading in some cases to the formation of solketila esters with moderate yields. This hypothesis has been proven, used a lower carbon alcohol, such as methanol, which reacted with linoleic and oleic acid in the presence of the catalytic mixture SiO2 -SO3H, for the production of methyl esters. The results obtained demonstrate the synthesis of methyl oleate and methyl linoleate in the 15 min time, with yield around 96 to 98%. This has demonstrated that it is of fundamental importance the flow of the reactants into the pores of the catalyst. This suggests that to ensure the success of solketal reactions with higher carbonic acids the flow of these reagents should be facilitated and this can be obtained through the use of solvente.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-01T11:57:07Z No. of bitstreams: 1 KeversonGomesDeOliveira_DISSERT.pdf: 1451007 bytes, checksum: 6336e55175d2d79eeb0023f6b024fb45 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-02T14:34:52Z (GMT) No. of bitstreams: 1 KeversonGomesDeOliveira_DISSERT.pdf: 1451007 bytes, checksum: 6336e55175d2d79eeb0023f6b024fb45 (MD5) / Made available in DSpace on 2017-08-02T14:34:52Z (GMT). No. of bitstreams: 1 KeversonGomesDeOliveira_DISSERT.pdf: 1451007 bytes, checksum: 6336e55175d2d79eeb0023f6b024fb45 (MD5) Previous issue date: 2017-04-10 / O aumento gradativo do uso de biodiesel na matriz energ?tica brasileira, como combust?vel em misturas biodiesel/diesel, tem incentivado a pesquisa por m?todos mais eficazes de obten??o e controle dos processos oxidativos deste biocombust?vel, buscando maior qualidade do produto. Neste trabalho, foram sintetizados biodiesel de oleaginosas do algod?o e da soja, e antioxidantes naturais (Passiflora edullis, Punica granatum, Syzygium aromaticum, respectivamente, maracuj?, rom? e cravo). O biodiesel proveniente da Refinaria Potiguar Clara Clamar?o, RPCC, foi utilizado para compara??o. A s?ntese dos biodiesel deste trabalho, ocorreu por cat?lise homog?nea, com KOH e, cat?lise heterog?nea, com catalisadores baseados em s?licas impregnadas por metais s?dio e pot?ssio, denominados CAT1 e CAT2. Os biodiesel produzidos foram utilizados em misturas combust?veis biodiesel/diesel, na propor??o volum?trica de 10% e 15%. As propriedades f?sico-qu?micas dos combust?veis produzidos, tais como, viscosidade e densidade (ASTM D7042), ponto de fulgor (ASTM D93), ponto de n?voa (ASTM D2500), ponto de fluidez (ASTM D97) e ponto de entupimento (ASTM D6371) foram determinadas segundo as normas da American Society for Testing and Materials ? ASTM, de acordo com as especifica??es definidas pela Ag?ncia Nacional de Petr?leo, G?s Natural e Biocombust?vel ? ANP. Os antioxidantes obtidos, atrav?s de extra??o alco?lica com octanol, foram caracterizados por espectroscopia na regi?o do infravermelho com transformada de Fourier (FTIR). Os espectros de FTIR apresentaram bandas em torno de 3000 cm-1 referentes ? deforma??o axial C-H de arom?ticos, 1601 cm-1 e 1460 cm-1 atribu?das ? deforma??o axial de C=C do anel arom?tico, que s?o t?picas de compostos fen?licos que comp?e os principais antioxidantes. O m?todo Rancimat foi utilizado para determinar o Per?odo de Indu??o (PI), do biodiesel de soja e o de algod?o com os antioxidantes naturais. O antioxidante obtido da esp?cie Passiflora edullis (maracuj?) apresentou PI de 5,23 h e 3,68 h, respectivamente, para o biodiesel de soja e algod?o. Os catalisadores produzidos neste trabalho foram caracterizados por difra??o de raios X (DRX), espectrometria de fluoresc?ncia de raios X (FRX) e FTIR. O CAT 1, apresentou tempo reacional de 30 min e rendimento de 85% para o biodiesel de soja produzido. O catalisador CAT2, produziu o biodiesel de soja em maior tempo reacional e rendimento de 75%, por?m apresentou elevada capacidade de reutiliza??o. Os antioxidantes naturais apresentaram atividade no biodiesel similar aos sint?ticos, contribuindo com metodologia de f?cil execu??o e menor custo. As misturas antioxidante/biodiesel/diesel permaneceram dentro dos limites de especifica??o exigidos pela ANP para comercializa??o do combust?vel. / The gradual increase in the use of biodiesel in the Brazilian energy matrix, as a fuel in biodiesel/diesel blends, has encouraged the search for more effective methods to obtaining and controlling the oxidative processo of this biofuel, looking for higher product quality. In this work we were synthesized biodiesel from cotton and soybean oil, and natural antioxidants (Passiflora edulis, Punica granatum, Syzygium aromaticum, respectively, passion fruit, pomegranate and clove). The biodiesel from the Potiguar Clara Clamar?o Refinery, RPCC, was used for comparison. The biodiesel synthesis occurred by homogeneous catalysis, with KOH, and heterogeneous catalysis, with catalysts based on silica impregnated with sodium and potassium metals, called CAT1 and CAT2. The produced biodiesel was used in biodiesel/diesel blends, in the volumetric proportion of 10% and 15%. The physicochemical properties of the produced fuels, such as kinematic viscosity and specific mass (ASTM D7042), flash point (ASTM D93), cloud point (ASTM D2500), pour point (ASTM D97) and cold filter plugging point (ASTM D6371) were determined following the American Society for Testing and Materials (ASTM) standards, according to the specifications defined by the Nacional Agency of Petroleum, Natural Gas and Biofuels (ANP). The antioxidants obtained through alcoholic extraction with octanol were characterized by Fourier transform infrared spectroscopy (FTIR). The FTIR spectra presented bands around 3000 cm-1 relative to C-H deformation of aromatic, 1601 cm-1 and 1460 cm-1 attributed to the axial deformation of C=C in the aromatic ring, which are typical from phenolic compounds that composes the antioxidants. The Rancimat method was used to determine the Induction Period (IP), of the biodiesel with the antioxidants. The antioxidant obtained from Passiflora edulis (passion fruit) showed IP of 5.23 h and 3.68 h for soybean and cotton biodiesel, respectively. The produced catalysts in this work were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF) and FTIR. CAT 1 presented a reaction time of 30 min and yield of 85% for the produced soybean biodiesel. The catalytic converter CAT2, produced the soybean biodiesel in a longer reaction time and yield of 75% but presented a higher reused capacity. The natural antioxidants presented activity in the biodiesel similar to the synthetic ones, contributing with an easy execution and low cost methodology. The antioxidant/biodiesel/diesel blends remained within the specification limits required by the ANP for fuel commercialization.

Made available in DSpace on 2014-12-17T15:42:16Z (GMT). No. of bitstreams: 1 LuizaPFCG_TESE.pdf: 3362653 bytes, checksum: 0de0a428d24980a5f9b2bf94d2e9214f (MD5) Previous issue date: 2012-08-23 / To overcome the challenge of meeting growing energy demand in a sustainable way, biodiesel has shown very promising as alternative energy can replace fossil fuels, even partially. Industrially, the biodiesel is produced by homogeneous transesterification reaction of vegetable oils in the presence of basic species used as catalysts. However, this process is the need for purification of the esters obtained and the removal of glycerin formed after the reaction. This context, the alternative catalysts have that can improve the process of biodiesel production, aiming to reduce costs and facilitate its production. In this study, the AlSBA-15 support with Si / Al ratio = 50 was synthesized, as like as the heterogeneous catalysts of zinc oxide and magnesium supported on mesoporous AlSBA-15 silica, in the concentrations of 5, 10, 15 and 30 %, relative to the support. The textural properties and structural characterization of catalysts and supports were determined by techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) coupled to the chemical analyzer, adsorption / desorption of N2, thermal analysis (TG / DTG), absorption spectroscopy in the infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Characterization results indicated that the support AlSBA-15 retained the hexagonal ordered after the incorporation of zinc oxide and magnesium oxide in the holder. For heterogeneous catalysts, ZnO-AlSBA-15, that was observed the presence of zinc oxide nanoparticles dispersed in the surface and interior channels of the mesoporous and microporous support. The catalytic activity was evaluated by the transesterification reaction of sunflower oil via methylic route, and some reaction parameters were optimized with the most active catalyst in biodiesel production by sunflower oil. For the series of heterogeneous catalysts, the sample with 30 % ZnO supported on AlSBA-15 showed a better conversion of triglyceride to methyl esters, about 95.41 % of reaction conditions: temperature 175 ?C, with molar ratio of 42:1, stirring at 200 rpm and under a pressure of 14 bar for 6 h. The catalyst MgO-AlSBA-15 showed no catalytic activity in the studied reactions / Para superar o desafio de atender a crescente demanda por energia de forma sustent?vel, o biodiesel tem se demonstrado bastante promissor como alternativa energ?tica, que possa substituir os combust?veis fosseis, mesmo que parcialmente. Industrialmente, o biodiesel ? produzido atrav?s de rea??o homog?nea de transesterifica??o de ?leos vegetais na presen?a de esp?cies b?sicas utilizadas como catalisadores. Entretanto, este processo h? a necessidade de purifica??o dos ?steres obtidos e a remo??o da glicerina formada ap?s a rea??o. Diante deste contexto, tem-se buscado catalisadores alternativos, que possa aprimorar o processo de produ??o de biodiesel, visando diminuir os custos e facilitar a sua produ??o. Neste trabalho, foram sintetizados o suporte AlSBA-15 na raz?o Si/Al = 50, e os catalisadores heterog?neos de ?xido de zinco e de magn?sio suportado sobre s?lica mesoporosa AlSBA-15, nas concentra??o de 5, 10, 15 e 30 %, com rela??o ao suporte. As propriedades texturais e a caracteriza??o estrutural dos catalisadores e do suporte foram determinadas pelas t?cnicas de: difratometria de raios X (DRX), microscopia eletr?nica de varredura (MEV), microscopia eletr?nica de transmiss?o (MET) acoplada ao analisador qu?mico, adsor??o/dessor??o de N2, an?lise t?rmica (TG/DTG), espectroscopia de absor??o na regi?o do infravermelho (FTIR) e espectroscopia fotoeletr?nica de raios X (XPS). Os resultados de caracteriza??o indicaram que o suporte AlSBA-15 preservou a estrutura hexagonal ordenada, ap?s a incorpora??o do ?xido de zinco e do ?xido de magn?sio no suporte. Em rela??o aos catalisadores heterog?neos, ZnO-AlSBA-15, observou-se a presen?a de nanopart?culas de ?xido de zinco dispersas na superf?cie e no interior dos canais microporosos e mesoporosos do suporte. A atividade catal?tica foi avaliada pela rea??o de transesterifica??o do ?leo de girassol via rota met?lica, e alguns par?metros reacionais foram otimizados com o catalisador mais ativo na produ??o de biodiesel pelo ?leo de girassol. Para as s?ries de catalisadores heterog?neos, a amostra com 30 % ZnO suportado na AlSBA-15 apresentou melhor convers?o dos triglicer?deos em ?steres met?licos, cerca de 95,41 %, nas condi??es reacional de: temperatura de 175 ?C, com raz?o molar de 42:1, em agita??o de 200 rpm e sob press?o de 14 bar durante 6 h. O catalisador MgO-AlSBA-15 n?o apresentou atividade catal?tica nas rea??es estudadas