Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41
Autor(a) principal: | |
---|---|
Data de Publicação: | 2020 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/13346 |
Resumo: | The synthesis of biodiesel, through transesterification, occurs industrially in the presence of basic homogeneous catalysts, where others steps are necessary, such as washing and neutralization of the final product due to the difficulty in separating the catalyst, which does not occur in heterogeneous routes. In this sense, the use of mesoporous hybrid silicas containing organic cations, as heterogeneous catalysts, is very effective in the transesterification reaction, since the presence of siloxide sites (≡SiO-) increases their catalytic activity. Therefore, the objective of this work was the synthesis of basic silicas and their subsequent application in the transesterification of different ethyl esters, as model reactions, in order to verify the influence of the size of the ester chain in the reaction in addition to the adjustment of kinetic models and determining the parameters of each reaction. The catalysts were synthesized using the classic synthesis of CTA-MCM-41 and also with the 2-ethylhexyl acrylate monomer, in a monomer / surfactant ratio equal to 0.2 and with the post-synthesis irradiation method. The kinetic models were adjusted to the reactions using only CTA-MCM-41 as a catalyst. By X-ray diffractometry (XRD) it was possible to verify the formation of the hexagonal structure of the silicas and the expansion of the irradiated silica channel. Scanning electron microscopy (SEM) and transmission electron microscopy showed that the catalysts do not differ in morphology and that they have cylindrical tubes ordered in a single direction. In addition, thermogravimetry (TG), spectroscopy in the infrared region (FTIR-ATR) and elementary analysis (CHN), confirmed the presence of the monomer in the irradiated silica. It was also found that the increase in the size of the ester chain of the model reactions implies a reduction in catalytic activity, probably due to both inductive effects and diffusion restrictions with the increase in the size of the carbon chain. The pseudo-first order model showed better adjustment to the reaction kinetics, and activation energies were obtained for each of the reactions, which varied between 41.29-48.30 kJ / mol as the carbon chain (acetate-pentanoate). These values were found to be within the range of the literature for transesterification of monoesters using basic heterogeneous catalysts. |
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Paula, Luana do Nascimento Rocha deCardoso, Dilsonhttp://lattes.cnpq.br/2462847535959232http://lattes.cnpq.br/13492120854608366fba3e74-1790-44e7-922f-39d4d2ba41592020-10-16T15:07:01Z2020-10-16T15:07:01Z2020-02-28PAULA, Luana do Nascimento Rocha de. Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41. 2020. Dissertação (Mestrado em Engenharia Química) – Universidade Federal de São Carlos, São Carlos, 2020. Disponível em: https://repositorio.ufscar.br/handle/ufscar/13346.https://repositorio.ufscar.br/handle/ufscar/13346The synthesis of biodiesel, through transesterification, occurs industrially in the presence of basic homogeneous catalysts, where others steps are necessary, such as washing and neutralization of the final product due to the difficulty in separating the catalyst, which does not occur in heterogeneous routes. In this sense, the use of mesoporous hybrid silicas containing organic cations, as heterogeneous catalysts, is very effective in the transesterification reaction, since the presence of siloxide sites (≡SiO-) increases their catalytic activity. Therefore, the objective of this work was the synthesis of basic silicas and their subsequent application in the transesterification of different ethyl esters, as model reactions, in order to verify the influence of the size of the ester chain in the reaction in addition to the adjustment of kinetic models and determining the parameters of each reaction. The catalysts were synthesized using the classic synthesis of CTA-MCM-41 and also with the 2-ethylhexyl acrylate monomer, in a monomer / surfactant ratio equal to 0.2 and with the post-synthesis irradiation method. The kinetic models were adjusted to the reactions using only CTA-MCM-41 as a catalyst. By X-ray diffractometry (XRD) it was possible to verify the formation of the hexagonal structure of the silicas and the expansion of the irradiated silica channel. Scanning electron microscopy (SEM) and transmission electron microscopy showed that the catalysts do not differ in morphology and that they have cylindrical tubes ordered in a single direction. In addition, thermogravimetry (TG), spectroscopy in the infrared region (FTIR-ATR) and elementary analysis (CHN), confirmed the presence of the monomer in the irradiated silica. It was also found that the increase in the size of the ester chain of the model reactions implies a reduction in catalytic activity, probably due to both inductive effects and diffusion restrictions with the increase in the size of the carbon chain. The pseudo-first order model showed better adjustment to the reaction kinetics, and activation energies were obtained for each of the reactions, which varied between 41.29-48.30 kJ / mol as the carbon chain (acetate-pentanoate). These values were found to be within the range of the literature for transesterification of monoesters using basic heterogeneous catalysts.A síntese do biodiesel, por meio da transesterificação, ocorre industrialmente na presença de catalisadores homogêneos básicos, onde são necessárias etapas extras, como lavagem e neutralização do produto final devido à dificuldade de separação do catalisador, o que não ocorre em rotas heterogêneas. Nesse sentido, a utilização de sílicas híbridas mesoporosas contendo cátions orgânicos, como catalisadores heterogêneos, é bastante eficaz na reação de transesterificação, uma vez que a presença de sítios silóxi (≡SiO-) eleva a sua atividade catalítica. Portanto, o objetivo deste trabalho foi a síntese de sílicas básicas e sua posterior aplicação na transesterificação de diferentes ésteres etílicos, como reações modelo, com o intuito de verificar a influência do tamanho da cadeia do éster na reação além do ajuste de modelos cinéticos e determinação dos parâmetros de cada uma das reações. Os catalisadores foram sintetizados utilizando a síntese clássica da CTA-MCM-41 e também com o monômero acrilato de 2-etil-hexila, com uma razão monômero/surfactante igual a 0,2 e método de irradiação pós-síntese. Os modelos cinéticos foram ajustados às reações utilizando apenas a CTA-MCM-41 como catalisador. Por difratometria de raios-X (DRX) foi possível verificar a formação da estrutura hexagonal dos poros à longo alcance e a expansão do canal da sílica irradiada. A microscopia eletrônica de varredura (MEV) e a microscopia eletrônica de transmissão (MET) mostraram que os catalisadores não diferem em morfologia e que possuem tubos cilíndricos ordenados em uma única direção. Além disso, a termogravimetria (TG), a espectroscopia na região do infravermelho (FTIR-ATR) e a análise elementar (CHN), confirmaram a presença do monômero na sílica irradiada. Também foi constatado que o aumento do tamanho da cadeia do éster das reações modelo implica na redução da atividade catalítica devido, provavelmente, tanto a efeitos indutivos quanto a restrições difusionais com o aumento do tamanho da cadeia carbônica. O modelo de pseudo-primeira ordem apresentou melhor ajuste às cinéticas reacionais, e a partir dele foram obtidas energias de ativação para cada uma das reações que variaram entre 41,29-48,30 kJ/mol conforme houve o aumento da cadeia carbônica (acetato de etila à pentanoato de etila). Esses valores se mostraram dentro da faixa da literatura para transesterificação de monoésteres usando catalisadores heterogêneos básicos.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq: 132824/2018-3porUniversidade Federal de São CarlosCâmpus São CarlosPrograma de Pós-Graduação em Engenharia Química - PPGEQUFSCarAttribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/info:eu-repo/semantics/openAccessCTA-MCM-41TransesterificaçãoÉsteres etílicosModelagem cinéticaTransesterificationEthyl estersKinetic modelingENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICAENGENHARIAS::ENGENHARIA QUIMICATransesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41Transesterification of ethyl esters and kinetic study using CTA-MCM-41 silicainfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesis60060045193456-2aac-47ce-8120-3995d1ca2a46reponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALDissertação_Luana Paula.pdfDissertação_Luana Paula.pdfDissertação de mestradoapplication/pdf2873929https://repositorio.ufscar.br/bitstream/ufscar/13346/1/Disserta%c3%a7%c3%a3o_Luana%20Paula.pdf85677d9f55d6dd0cdc06391ac5ff0a5cMD51Carta Comprovante_Luana Paula_ Dissertação.pdfCarta Comprovante_Luana Paula_ Dissertação.pdfCarta comprovante da dissertaçãoapplication/pdf93203https://repositorio.ufscar.br/bitstream/ufscar/13346/2/Carta%20Comprovante_Luana%20Paula_%20Disserta%c3%a7%c3%a3o.pdfe63ec41732a4148f96a96e4cad7277ceMD52CC-LICENSElicense_rdflicense_rdfapplication/rdf+xml; charset=utf-8811https://repositorio.ufscar.br/bitstream/ufscar/13346/3/license_rdfe39d27027a6cc9cb039ad269a5db8e34MD53TEXTDissertação_Luana Paula.pdf.txtDissertação_Luana Paula.pdf.txtExtracted texttext/plain154718https://repositorio.ufscar.br/bitstream/ufscar/13346/4/Disserta%c3%a7%c3%a3o_Luana%20Paula.pdf.txt6001cad5b2c772810c0c99ab15d2cc7bMD54Carta Comprovante_Luana Paula_ Dissertação.pdf.txtCarta Comprovante_Luana Paula_ Dissertação.pdf.txtExtracted texttext/plain1248https://repositorio.ufscar.br/bitstream/ufscar/13346/6/Carta%20Comprovante_Luana%20Paula_%20Disserta%c3%a7%c3%a3o.pdf.txt3577def43c43323aafbf61cb809cd0c2MD56THUMBNAILDissertação_Luana Paula.pdf.jpgDissertação_Luana Paula.pdf.jpgIM Thumbnailimage/jpeg5649https://repositorio.ufscar.br/bitstream/ufscar/13346/5/Disserta%c3%a7%c3%a3o_Luana%20Paula.pdf.jpgd12eddd682320f3896b63d4adbc3aad9MD55Carta Comprovante_Luana Paula_ Dissertação.pdf.jpgCarta Comprovante_Luana Paula_ Dissertação.pdf.jpgIM Thumbnailimage/jpeg12336https://repositorio.ufscar.br/bitstream/ufscar/13346/7/Carta%20Comprovante_Luana%20Paula_%20Disserta%c3%a7%c3%a3o.pdf.jpg2cd8bf44eef4f3994d13fbc0c0f87078MD57ufscar/133462023-09-18 18:32:02.874oai:repositorio.ufscar.br:ufscar/13346Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:32:02Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
dc.title.alternative.eng.fl_str_mv |
Transesterification of ethyl esters and kinetic study using CTA-MCM-41 silica |
title |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
spellingShingle |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 Paula, Luana do Nascimento Rocha de CTA-MCM-41 Transesterificação Ésteres etílicos Modelagem cinética Transesterification Ethyl esters Kinetic modeling ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA ENGENHARIAS::ENGENHARIA QUIMICA |
title_short |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
title_full |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
title_fullStr |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
title_full_unstemmed |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
title_sort |
Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41 |
author |
Paula, Luana do Nascimento Rocha de |
author_facet |
Paula, Luana do Nascimento Rocha de |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/1349212085460836 |
dc.contributor.author.fl_str_mv |
Paula, Luana do Nascimento Rocha de |
dc.contributor.advisor1.fl_str_mv |
Cardoso, Dilson |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/2462847535959232 |
dc.contributor.authorID.fl_str_mv |
6fba3e74-1790-44e7-922f-39d4d2ba4159 |
contributor_str_mv |
Cardoso, Dilson |
dc.subject.por.fl_str_mv |
CTA-MCM-41 Transesterificação Ésteres etílicos Modelagem cinética |
topic |
CTA-MCM-41 Transesterificação Ésteres etílicos Modelagem cinética Transesterification Ethyl esters Kinetic modeling ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA ENGENHARIAS::ENGENHARIA QUIMICA |
dc.subject.eng.fl_str_mv |
Transesterification Ethyl esters Kinetic modeling |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA ENGENHARIAS::ENGENHARIA QUIMICA |
description |
The synthesis of biodiesel, through transesterification, occurs industrially in the presence of basic homogeneous catalysts, where others steps are necessary, such as washing and neutralization of the final product due to the difficulty in separating the catalyst, which does not occur in heterogeneous routes. In this sense, the use of mesoporous hybrid silicas containing organic cations, as heterogeneous catalysts, is very effective in the transesterification reaction, since the presence of siloxide sites (≡SiO-) increases their catalytic activity. Therefore, the objective of this work was the synthesis of basic silicas and their subsequent application in the transesterification of different ethyl esters, as model reactions, in order to verify the influence of the size of the ester chain in the reaction in addition to the adjustment of kinetic models and determining the parameters of each reaction. The catalysts were synthesized using the classic synthesis of CTA-MCM-41 and also with the 2-ethylhexyl acrylate monomer, in a monomer / surfactant ratio equal to 0.2 and with the post-synthesis irradiation method. The kinetic models were adjusted to the reactions using only CTA-MCM-41 as a catalyst. By X-ray diffractometry (XRD) it was possible to verify the formation of the hexagonal structure of the silicas and the expansion of the irradiated silica channel. Scanning electron microscopy (SEM) and transmission electron microscopy showed that the catalysts do not differ in morphology and that they have cylindrical tubes ordered in a single direction. In addition, thermogravimetry (TG), spectroscopy in the infrared region (FTIR-ATR) and elementary analysis (CHN), confirmed the presence of the monomer in the irradiated silica. It was also found that the increase in the size of the ester chain of the model reactions implies a reduction in catalytic activity, probably due to both inductive effects and diffusion restrictions with the increase in the size of the carbon chain. The pseudo-first order model showed better adjustment to the reaction kinetics, and activation energies were obtained for each of the reactions, which varied between 41.29-48.30 kJ / mol as the carbon chain (acetate-pentanoate). These values were found to be within the range of the literature for transesterification of monoesters using basic heterogeneous catalysts. |
publishDate |
2020 |
dc.date.accessioned.fl_str_mv |
2020-10-16T15:07:01Z |
dc.date.available.fl_str_mv |
2020-10-16T15:07:01Z |
dc.date.issued.fl_str_mv |
2020-02-28 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
PAULA, Luana do Nascimento Rocha de. Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41. 2020. Dissertação (Mestrado em Engenharia Química) – Universidade Federal de São Carlos, São Carlos, 2020. Disponível em: https://repositorio.ufscar.br/handle/ufscar/13346. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/13346 |
identifier_str_mv |
PAULA, Luana do Nascimento Rocha de. Transesterificação de ésteres etílicos e estudo cinético usando a sílica CTA-MCM-41. 2020. Dissertação (Mestrado em Engenharia Química) – Universidade Federal de São Carlos, São Carlos, 2020. Disponível em: https://repositorio.ufscar.br/handle/ufscar/13346. |
url |
https://repositorio.ufscar.br/handle/ufscar/13346 |
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por |
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600 600 |
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45193456-2aac-47ce-8120-3995d1ca2a46 |
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Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ info:eu-repo/semantics/openAccess |
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Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ |
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openAccess |
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Universidade Federal de São Carlos Câmpus São Carlos |
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Programa de Pós-Graduação em Engenharia Química - PPGEQ |
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UFSCar |
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Universidade Federal de São Carlos Câmpus São Carlos |
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