Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica
Autor(a) principal: | |
---|---|
Data de Publicação: | 2022 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/15884 |
Resumo: | The application of zeolites in catalysis is restricted when bulkier molecules are involved, for example, in the manufacture of fine chemicals, where the reactant molecules are unable to access their micropores. A solution to this problem could be the synthesis of zeolites containing mesopores to improve accessibility to sites. Zeolites have intrinsic basicity, due to residual negative charges in their framework, which are generated by the presence of trivalent aluminum atoms with tetrahedral coordination. The functionalization of the surface of zeolites with amine groups, through the anchoring of silanes containing basic nitrogenous species, is one strategy to improve their basicity. In this context, this work studied the synthesis of 4A zeolites through the constructive method (bottom-up) using the organosilane surfactant [3 (trimethoxysilyl) propyl] octadecyldimethyl ammonium chloride (TPOAC) as mesopores generator at different concentrations in the synthesis mixture (TPOAC/Al2O3= 0-0.09). These zeolites were evaluated in the Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate, which is influenced by the accessibility to the catalytic sites, due to the volume of the molecules involved. This study also evaluated the improvement of the basicity of zeolites through the functionalization of their surface with amine groups, for this, the zeolite containing the highest amount of mesopores, and the conventional zeolite were treated with aminopropil-trimetoxisilano (APTMS). 4A zeolites with mesopores were formed in the presence of TPOAC at the different concentrations evaluated, showing an increase in the external surface. The benzaldehyde conversions were higher when using zeolites with mesopores instead of conventional 4A, due to the improved accessibility of the to the catalytic sites. In addition, the reaction catalyzed by zeolite with mesopores has a lower activation energy than that catalyzed by conventional 4A zeolite. It was not possible to anchor APTMS on the surface of the conventional zeolite, probably due to the low external surface and consequent lack of available silanol groups that can react with the silane. On the other hand, the functionalization of zeolite with mesopores was possible, due to its high surface that provides a higher amount of silanol groups compared to the external surface of the conventional zeolite crystal. Consequently, zeolite with mesopores treated with APTMS has superior catalytic activity in Knoevenagel condensation, due to improved accessibility and addition of catalytic sites. |
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Silva, Juliana Floriano daCardoso, Dilsonhttp://lattes.cnpq.br/2462847535959232http://lattes.cnpq.br/4674602775309738f9f3335b-4699-4f54-90e2-90bee64ad5d02022-04-20T18:21:23Z2022-04-20T18:21:23Z2022-03-28SILVA, Juliana Floriano da. Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica. 2022. Tese (Doutorado em Engenharia Química) – Universidade Federal de São Carlos, São Carlos, 2022. Disponível em: https://repositorio.ufscar.br/handle/ufscar/15884.https://repositorio.ufscar.br/handle/ufscar/15884The application of zeolites in catalysis is restricted when bulkier molecules are involved, for example, in the manufacture of fine chemicals, where the reactant molecules are unable to access their micropores. A solution to this problem could be the synthesis of zeolites containing mesopores to improve accessibility to sites. Zeolites have intrinsic basicity, due to residual negative charges in their framework, which are generated by the presence of trivalent aluminum atoms with tetrahedral coordination. The functionalization of the surface of zeolites with amine groups, through the anchoring of silanes containing basic nitrogenous species, is one strategy to improve their basicity. In this context, this work studied the synthesis of 4A zeolites through the constructive method (bottom-up) using the organosilane surfactant [3 (trimethoxysilyl) propyl] octadecyldimethyl ammonium chloride (TPOAC) as mesopores generator at different concentrations in the synthesis mixture (TPOAC/Al2O3= 0-0.09). These zeolites were evaluated in the Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate, which is influenced by the accessibility to the catalytic sites, due to the volume of the molecules involved. This study also evaluated the improvement of the basicity of zeolites through the functionalization of their surface with amine groups, for this, the zeolite containing the highest amount of mesopores, and the conventional zeolite were treated with aminopropil-trimetoxisilano (APTMS). 4A zeolites with mesopores were formed in the presence of TPOAC at the different concentrations evaluated, showing an increase in the external surface. The benzaldehyde conversions were higher when using zeolites with mesopores instead of conventional 4A, due to the improved accessibility of the to the catalytic sites. In addition, the reaction catalyzed by zeolite with mesopores has a lower activation energy than that catalyzed by conventional 4A zeolite. It was not possible to anchor APTMS on the surface of the conventional zeolite, probably due to the low external surface and consequent lack of available silanol groups that can react with the silane. On the other hand, the functionalization of zeolite with mesopores was possible, due to its high surface that provides a higher amount of silanol groups compared to the external surface of the conventional zeolite crystal. Consequently, zeolite with mesopores treated with APTMS has superior catalytic activity in Knoevenagel condensation, due to improved accessibility and addition of catalytic sites.A aplicação de zeólitas na catálise é restrita quando estão envolvidas moléculas mais volumosas, como por exemplo, na fabricação de produtos de química fina, onde as moléculas dos reagentes são incapazes de acessar seus microporos. Uma solução para este problema, seria a síntese de zeólitas contendo mesoporos para melhoria da acessibilidade aos sítios. As zeólitas possuem basicidade intrínseca, devido a uma carga residual negativa em sua estrutura, a qual é gerada pela presença de átomos de alumínio trivalente com coordenação tetraédrica. A funcionalização da superfície das zeólitas com grupos amina, por meio da ancoragem de silanos contendo substâncias nitrogenadas básicas é uma estratégia para melhoria de sua basicidade. Nesse contexto, este trabalho estudou a síntese de zeólitas 4A por meio do método construtivo (bottom-up), utilizando o surfactante organossilano cloreto de [3-(trimetoxissilil) propil] octadecildimetil amônio (TPOAC) como formador de mesoporos, em diferentes concentrações na mistura de síntese (TPOAC/Al2O3= 0 0,09). Essas zeólitas foram avaliadas na condensação de Knoevenagel entre o benzaldeído e o cianoacetato de etila, a qual é influenciada pela acessibilidade aos sítios catalíticos, devido ao volume das moléculas envolvidas. Esse estudo também avaliou a melhoria da basicidade das zeólitas por meio da funcionalização de sua superfície com grupos amina, para isso, a zeólita contendo maior quantidade de mesoporos e a zeólita convencional, foram tratadas com aminopropil-trimetoxisilano (APTMS). Zeólitas 4A com mesoporos foram formadas na presença do TPOAC nas diferentes concentrações avaliadas apresentando um aumento na superfície externa, em comparação com a zeólita convencional. As conversões do benzaldeído foram maiores quando utilizadas zeólitas com mesoporos ao invés da 4A convencional, devido à melhoria da acessibilidade das moléculas aos sítios catalíticos. Além disso, a reação catalisada pela zeólita com mesoporos possui menor energia de ativação, em relação à catalisada pela zeólita 4A convencional. Observou-se que não foi possível a ancoragem do APTMS na superfície da zeólita convencional, provavelmente devido à baixa superfície externa e consequente falta de grupos silanóis disponíveis para reação com o silano. Em contrapartida, foi possível a funcionalização da zeólita com mesoporos, devido à sua superfície elevada que fornece quantidade superior de grupos silanóis em comparação com a superfície externa do cristal de zeólita convencional. Consequentemente, a zeólita com mesoporos tratada com APTMS possui atividade catalítica superior na condensação de Knoevenagel, devido a melhoria da acessibilidade e acréscimo de sítios catalíticos.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)141843/2020-9porUniversidade 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/openAccessZeólitasMesoporosOrganossilanoAminaCatálise básicaZeolitesMesoporesOrganosilaneAmineBase catalysisENGENHARIAS::ENGENHARIA QUIMICAEstudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básicaStudies on accessibility of zeolite sites for application in basic catalysisinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis60060045193456-2aac-47ce-8120-3995d1ca2a46reponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALJuliana-PPGEQ-Tese_Final.pdfJuliana-PPGEQ-Tese_Final.pdfVersão final da teseapplication/pdf2405481https://repositorio.ufscar.br/bitstream/ufscar/15884/1/Juliana-PPGEQ-Tese_Final.pdf6a35577b7f491e18a9fb66b0f5a77875MD51Juliana_Carta Comprovante_Versao Final_DR (1).pdfJuliana_Carta Comprovante_Versao Final_DR (1).pdfCarta comprovanteapplication/pdf95645https://repositorio.ufscar.br/bitstream/ufscar/15884/3/Juliana_Carta%20Comprovante_Versao%20Final_DR%20%281%29.pdfbfa824445fcf913ba4f15040d548aa97MD53CC-LICENSElicense_rdflicense_rdfapplication/rdf+xml; charset=utf-8811https://repositorio.ufscar.br/bitstream/ufscar/15884/4/license_rdfe39d27027a6cc9cb039ad269a5db8e34MD54TEXTJuliana-PPGEQ-Tese_Final.pdf.txtJuliana-PPGEQ-Tese_Final.pdf.txtExtracted texttext/plain137289https://repositorio.ufscar.br/bitstream/ufscar/15884/5/Juliana-PPGEQ-Tese_Final.pdf.txt1f89f5b100c3a1dd53bcf88df4d6c428MD55Juliana_Carta Comprovante_Versao Final_DR (1).pdf.txtJuliana_Carta Comprovante_Versao Final_DR (1).pdf.txtExtracted texttext/plain1375https://repositorio.ufscar.br/bitstream/ufscar/15884/7/Juliana_Carta%20Comprovante_Versao%20Final_DR%20%281%29.pdf.txta1a69cd2f692b56f7249a40ac3a9434dMD57THUMBNAILJuliana-PPGEQ-Tese_Final.pdf.jpgJuliana-PPGEQ-Tese_Final.pdf.jpgIM Thumbnailimage/jpeg5981https://repositorio.ufscar.br/bitstream/ufscar/15884/6/Juliana-PPGEQ-Tese_Final.pdf.jpgb5425d65badd88db6de4d9265e99b69fMD56Juliana_Carta Comprovante_Versao Final_DR (1).pdf.jpgJuliana_Carta Comprovante_Versao Final_DR (1).pdf.jpgIM Thumbnailimage/jpeg10793https://repositorio.ufscar.br/bitstream/ufscar/15884/8/Juliana_Carta%20Comprovante_Versao%20Final_DR%20%281%29.pdf.jpg67df356a95d3bf77938381a9116fea12MD58ufscar/158842023-09-18 18:32:16.256oai:repositorio.ufscar.br:ufscar/15884Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:32:16Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
dc.title.alternative.eng.fl_str_mv |
Studies on accessibility of zeolite sites for application in basic catalysis |
title |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
spellingShingle |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica Silva, Juliana Floriano da Zeólitas Mesoporos Organossilano Amina Catálise básica Zeolites Mesopores Organosilane Amine Base catalysis ENGENHARIAS::ENGENHARIA QUIMICA |
title_short |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
title_full |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
title_fullStr |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
title_full_unstemmed |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
title_sort |
Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica |
author |
Silva, Juliana Floriano da |
author_facet |
Silva, Juliana Floriano da |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/4674602775309738 |
dc.contributor.author.fl_str_mv |
Silva, Juliana Floriano da |
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 |
f9f3335b-4699-4f54-90e2-90bee64ad5d0 |
contributor_str_mv |
Cardoso, Dilson |
dc.subject.por.fl_str_mv |
Zeólitas Mesoporos Organossilano Amina Catálise básica |
topic |
Zeólitas Mesoporos Organossilano Amina Catálise básica Zeolites Mesopores Organosilane Amine Base catalysis ENGENHARIAS::ENGENHARIA QUIMICA |
dc.subject.eng.fl_str_mv |
Zeolites Mesopores Organosilane Amine Base catalysis |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA QUIMICA |
description |
The application of zeolites in catalysis is restricted when bulkier molecules are involved, for example, in the manufacture of fine chemicals, where the reactant molecules are unable to access their micropores. A solution to this problem could be the synthesis of zeolites containing mesopores to improve accessibility to sites. Zeolites have intrinsic basicity, due to residual negative charges in their framework, which are generated by the presence of trivalent aluminum atoms with tetrahedral coordination. The functionalization of the surface of zeolites with amine groups, through the anchoring of silanes containing basic nitrogenous species, is one strategy to improve their basicity. In this context, this work studied the synthesis of 4A zeolites through the constructive method (bottom-up) using the organosilane surfactant [3 (trimethoxysilyl) propyl] octadecyldimethyl ammonium chloride (TPOAC) as mesopores generator at different concentrations in the synthesis mixture (TPOAC/Al2O3= 0-0.09). These zeolites were evaluated in the Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate, which is influenced by the accessibility to the catalytic sites, due to the volume of the molecules involved. This study also evaluated the improvement of the basicity of zeolites through the functionalization of their surface with amine groups, for this, the zeolite containing the highest amount of mesopores, and the conventional zeolite were treated with aminopropil-trimetoxisilano (APTMS). 4A zeolites with mesopores were formed in the presence of TPOAC at the different concentrations evaluated, showing an increase in the external surface. The benzaldehyde conversions were higher when using zeolites with mesopores instead of conventional 4A, due to the improved accessibility of the to the catalytic sites. In addition, the reaction catalyzed by zeolite with mesopores has a lower activation energy than that catalyzed by conventional 4A zeolite. It was not possible to anchor APTMS on the surface of the conventional zeolite, probably due to the low external surface and consequent lack of available silanol groups that can react with the silane. On the other hand, the functionalization of zeolite with mesopores was possible, due to its high surface that provides a higher amount of silanol groups compared to the external surface of the conventional zeolite crystal. Consequently, zeolite with mesopores treated with APTMS has superior catalytic activity in Knoevenagel condensation, due to improved accessibility and addition of catalytic sites. |
publishDate |
2022 |
dc.date.accessioned.fl_str_mv |
2022-04-20T18:21:23Z |
dc.date.available.fl_str_mv |
2022-04-20T18:21:23Z |
dc.date.issued.fl_str_mv |
2022-03-28 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
SILVA, Juliana Floriano da. Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica. 2022. Tese (Doutorado em Engenharia Química) – Universidade Federal de São Carlos, São Carlos, 2022. Disponível em: https://repositorio.ufscar.br/handle/ufscar/15884. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/15884 |
identifier_str_mv |
SILVA, Juliana Floriano da. Estudos sobre a acessibilidade aos sítios de zeólitas para aplicação em catálise básica. 2022. Tese (Doutorado em Engenharia Química) – Universidade Federal de São Carlos, São Carlos, 2022. Disponível em: https://repositorio.ufscar.br/handle/ufscar/15884. |
url |
https://repositorio.ufscar.br/handle/ufscar/15884 |
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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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