Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas
Autor(a) principal: | |
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Data de Publicação: | 2015 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da UERJ |
Texto Completo: | http://www.bdtd.uerj.br/handle/1/12031 |
Resumo: | The methylic transesterification of vegetable oils catalyzed by sodium or potassium hydroxides or alkoxides is carried out in homogeneous media at a low reaction temperature, even on an industrial scale. However, the homogeneous reaction has some disadvantages such as the sensitivity of the catalyst to the presence of free fatty acids and/or water in the oil feedstock, which causes the occurrence of undesirable saponification reactions. On the other hand, the use of basic solid catalysts appears as a promising alternative to conventional homogeneous processes, since it reduces the occurrence of undesirable reactions of saponification and decreases the process costs due to the reduction of the number of operations associated. In a previous studies of the group, Mg/La catalysts with different chemical compositions (9:1, 1:1 and 1:9) showed good results for the production of methyl esters via transesterification reaction. However, it was not possible to make a correlation between catalytic activity and the basic properties when the whole series was considered. Therefore, the realization of a fundamental study based on model reactions and the use of probe molecules may lead to the comprehension of the surface properties of these catalysts. Thus, in this work, the reaction between methanol and ethyl acetate catalyzed by a series of Mg/La-catalysts was studied using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) coupled to mass spectrometry (QMS) aiming at identify the intermediates and products formed to determine the reaction route. The analysis of X-ray diffraction showed that the precursors are mainly hydrated carbonates of magnesium (Mg/La 1:1 and 9:1) and lanthanum (Mg/La 1:9). The TG profiles and in situ X-ray difratograms obtained during the thermal decomposition of the precursors indicate that these carbonates decompose at 750 ºC or above. Temperature Programmed Desorption analysis carried out with probe molecules, methanol and ethyl acetate, showed a higher amount of methanol adsorbed on the catalyst surface. From the results obtained by DRIFTS-MS a reaction route for the transesterification reaction of methanol and ethyl acetate was proposed. The reaction occurs via adsorption of methanol and ethyl acetate on the catalyst surface. These adsorbed species react forming an adsorbed tetrahedral intermediate which undergoes rearrangement producing ethanol, methyl acetate, acetone and methane. Simultaneously, the methanol adsorbed as a monodentate methoxy specie is dehydrogenated forming formates species that are decomposed in CO2 and H2 |
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Cesar, Deborah Vargashttp://lattes.cnpq.br/1350917983266189Henriques, Cristiane Assumpçãohttp://lattes.cnpq.br/8669668633454299Toniolo, Fabio Souzahttp://lattes.cnpq.br/4183846294730007Bonfim, Rodrigo de Paiva Florohttp://lattes.cnpq.br/3034430315392022Santos, Luz Amparo Palaciohttp://lattes.cnpq.br/2277031732030434Sousa, Zilacleide da Silva Barroshttp://lattes.cnpq.br/4645101234879372http://lattes.cnpq.br/4251159130607488Gonçalves, Adão de Souza2021-01-06T19:37:25Z2015-09-222015-02-27GONÇALVES, Adão de Souza. Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas. 2015. 103 f. Dissertação (Mestrado em Processos Químicos e Meio Ambiente) - Universidade do Estado do Rio de Janeiro, Rio de Janeiro, 2015.http://www.bdtd.uerj.br/handle/1/12031The methylic transesterification of vegetable oils catalyzed by sodium or potassium hydroxides or alkoxides is carried out in homogeneous media at a low reaction temperature, even on an industrial scale. However, the homogeneous reaction has some disadvantages such as the sensitivity of the catalyst to the presence of free fatty acids and/or water in the oil feedstock, which causes the occurrence of undesirable saponification reactions. On the other hand, the use of basic solid catalysts appears as a promising alternative to conventional homogeneous processes, since it reduces the occurrence of undesirable reactions of saponification and decreases the process costs due to the reduction of the number of operations associated. In a previous studies of the group, Mg/La catalysts with different chemical compositions (9:1, 1:1 and 1:9) showed good results for the production of methyl esters via transesterification reaction. However, it was not possible to make a correlation between catalytic activity and the basic properties when the whole series was considered. Therefore, the realization of a fundamental study based on model reactions and the use of probe molecules may lead to the comprehension of the surface properties of these catalysts. Thus, in this work, the reaction between methanol and ethyl acetate catalyzed by a series of Mg/La-catalysts was studied using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) coupled to mass spectrometry (QMS) aiming at identify the intermediates and products formed to determine the reaction route. The analysis of X-ray diffraction showed that the precursors are mainly hydrated carbonates of magnesium (Mg/La 1:1 and 9:1) and lanthanum (Mg/La 1:9). The TG profiles and in situ X-ray difratograms obtained during the thermal decomposition of the precursors indicate that these carbonates decompose at 750 ºC or above. Temperature Programmed Desorption analysis carried out with probe molecules, methanol and ethyl acetate, showed a higher amount of methanol adsorbed on the catalyst surface. From the results obtained by DRIFTS-MS a reaction route for the transesterification reaction of methanol and ethyl acetate was proposed. The reaction occurs via adsorption of methanol and ethyl acetate on the catalyst surface. These adsorbed species react forming an adsorbed tetrahedral intermediate which undergoes rearrangement producing ethanol, methyl acetate, acetone and methane. Simultaneously, the methanol adsorbed as a monodentate methoxy specie is dehydrogenated forming formates species that are decomposed in CO2 and H2A transesterificação metílica em meio homogêneo é catalisada por bases, tais como hidróxidos e alcóxidos de sódio ou potássio e se processa em baixa temperatura de reação, mesmo em escala industrial. A utilização de catalisadores formados por sólidos básicos aparece como uma alternativa promissora aos processos homogêneos convencionais, tendo em vista as inúmeras vantagens como a redução da ocorrência das reações indesejáveis de saponificação e redução de custos dos processos pela diminuição do número de operações associadas. Em estudos anteriores realizados pelo grupo, catalisadores a base de Mg/La com diferentes composições químicas (9:1, 1:1 e 1:9) mostraram-se promissores para a obtenção de ésteres metílicos via reação de transesterificação, porém não foi possível fazer uma correlação entre atividade catalítica e as propriedades físico-químicas quando toda a série foi considerada. Assim, a realização de um estudo de caráter fundamental, baseado em reações modelo e uso de moléculas sonda, permite avançar no entendimento das propriedades de superfície destes catalisadores. Portanto, o presente trabalho estuda a reação entre metanol e acetato de etila em catalisadores a base de Mg/La utilizando espectroscopia de reflectância difusa no infravermelho com transformada de Fourier (DRIFTS) acoplada a espectrometria de massas (MS) identificando os intermediários e produtos formados para determinar a rota reacional. As análises de difração de raios X mostram que os precursores são predominantemente compostos por carbonatos hidratados de magnésio (Mg/La 1:1 e 9:1) e de lantânio (Mg/La 1:9). Os perfis de decomposição térmica e difratogramas de raios X obtidos a partir de tratamento térmico in situ indicaram que estes carbonatos se decompõem apenas a partir de 750 ºC. As análises de Dessorção a Temperatura Programada realizadas com moléculas sonda, metanol e acetato de etila, mostraram a adsorção em maior quantidade do metanol independente da composição química do sólido. A partir dos resultados obtidos por DRIFTS-MS foi proposta uma rota reacional para a reação de transesterificação do acetato de etila e metanol, que ocorre via adsorção do metanol e do acetato de etila na superfície do catalisador, seguida da formação de um intermediário tetraédrico formado pelas moléculas adsorvidas, que sofre um rearranjo formando etanol, acetato de metila, acetona e metano. Simultaneamente, parte do metanol adsorvido como metoxi monodentado é desidrogenado formando formiatos que são dessorvidos na forma de formaldeído e decompostos formando CO2 e H2Submitted by Boris Flegr (boris@uerj.br) on 2021-01-06T19:37:25Z No. of bitstreams: 1 Adao de Souza Goncalves.pdf: 1913604 bytes, checksum: 02dbabab859cdd0db57445d6c0597fd3 (MD5)Made available in DSpace on 2021-01-06T19:37:25Z (GMT). No. of bitstreams: 1 Adao de Souza Goncalves.pdf: 1913604 bytes, checksum: 02dbabab859cdd0db57445d6c0597fd3 (MD5) Previous issue date: 2015-02-27application/pdfporUniversidade do Estado do Rio de JaneiroPrograma de Pós-Graduação em Engenharia QuímicaUERJBRCentro de Tecnologia e Ciências::Instituto de QuímicaMethanolethyl acetateMg/La catalystsDRIFTS coupled to mass spectrometrytransesterification reactionMetanolacetato de etilacatalisadores Mg/LaDRIFTS acoplado a espectrometria de massasreação de transesterificaçãoCNPQ::ENGENHARIAS::ENGENHARIA QUIMICAEstudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massasStudy of the reaction between methanol and ethyl acetate on Mg/La catalysts by infrared spectroscopy coupled with mass spectrometryinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:Biblioteca Digital de Teses e Dissertações da UERJinstname:Universidade do Estado do Rio de Janeiro (UERJ)instacron:UERJORIGINALAdao de Souza Goncalves.pdfapplication/pdf1913604http://www.bdtd.uerj.br/bitstream/1/12031/1/Adao+de+Souza+Goncalves.pdf02dbabab859cdd0db57445d6c0597fd3MD511/120312024-02-27 15:36:07.217oai:www.bdtd.uerj.br:1/12031Biblioteca Digital de Teses e Dissertaçõeshttp://www.bdtd.uerj.br/PUBhttps://www.bdtd.uerj.br:8443/oai/requestbdtd.suporte@uerj.bropendoar:29032024-02-27T18:36:07Biblioteca Digital de Teses e Dissertações da UERJ - Universidade do Estado do Rio de Janeiro (UERJ)false |
dc.title.por.fl_str_mv |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
dc.title.alternative.eng.fl_str_mv |
Study of the reaction between methanol and ethyl acetate on Mg/La catalysts by infrared spectroscopy coupled with mass spectrometry |
title |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
spellingShingle |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas Gonçalves, Adão de Souza Methanol ethyl acetate Mg/La catalysts DRIFTS coupled to mass spectrometry transesterification reaction Metanol acetato de etila catalisadores Mg/La DRIFTS acoplado a espectrometria de massas reação de transesterificação CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
title_short |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
title_full |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
title_fullStr |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
title_full_unstemmed |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
title_sort |
Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas |
author |
Gonçalves, Adão de Souza |
author_facet |
Gonçalves, Adão de Souza |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Cesar, Deborah Vargas |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/1350917983266189 |
dc.contributor.advisor-co1.fl_str_mv |
Henriques, Cristiane Assumpção |
dc.contributor.advisor-co1Lattes.fl_str_mv |
http://lattes.cnpq.br/8669668633454299 |
dc.contributor.referee1.fl_str_mv |
Toniolo, Fabio Souza |
dc.contributor.referee1Lattes.fl_str_mv |
http://lattes.cnpq.br/4183846294730007 |
dc.contributor.referee2.fl_str_mv |
Bonfim, Rodrigo de Paiva Floro |
dc.contributor.referee2Lattes.fl_str_mv |
http://lattes.cnpq.br/3034430315392022 |
dc.contributor.referee3.fl_str_mv |
Santos, Luz Amparo Palacio |
dc.contributor.referee3Lattes.fl_str_mv |
http://lattes.cnpq.br/2277031732030434 |
dc.contributor.referee4.fl_str_mv |
Sousa, Zilacleide da Silva Barros |
dc.contributor.referee4Lattes.fl_str_mv |
http://lattes.cnpq.br/4645101234879372 |
dc.contributor.authorLattes.fl_str_mv |
http://lattes.cnpq.br/4251159130607488 |
dc.contributor.author.fl_str_mv |
Gonçalves, Adão de Souza |
contributor_str_mv |
Cesar, Deborah Vargas Henriques, Cristiane Assumpção Toniolo, Fabio Souza Bonfim, Rodrigo de Paiva Floro Santos, Luz Amparo Palacio Sousa, Zilacleide da Silva Barros |
dc.subject.eng.fl_str_mv |
Methanol ethyl acetate Mg/La catalysts DRIFTS coupled to mass spectrometry transesterification reaction |
topic |
Methanol ethyl acetate Mg/La catalysts DRIFTS coupled to mass spectrometry transesterification reaction Metanol acetato de etila catalisadores Mg/La DRIFTS acoplado a espectrometria de massas reação de transesterificação CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
dc.subject.por.fl_str_mv |
Metanol acetato de etila catalisadores Mg/La DRIFTS acoplado a espectrometria de massas reação de transesterificação |
dc.subject.cnpq.fl_str_mv |
CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
description |
The methylic transesterification of vegetable oils catalyzed by sodium or potassium hydroxides or alkoxides is carried out in homogeneous media at a low reaction temperature, even on an industrial scale. However, the homogeneous reaction has some disadvantages such as the sensitivity of the catalyst to the presence of free fatty acids and/or water in the oil feedstock, which causes the occurrence of undesirable saponification reactions. On the other hand, the use of basic solid catalysts appears as a promising alternative to conventional homogeneous processes, since it reduces the occurrence of undesirable reactions of saponification and decreases the process costs due to the reduction of the number of operations associated. In a previous studies of the group, Mg/La catalysts with different chemical compositions (9:1, 1:1 and 1:9) showed good results for the production of methyl esters via transesterification reaction. However, it was not possible to make a correlation between catalytic activity and the basic properties when the whole series was considered. Therefore, the realization of a fundamental study based on model reactions and the use of probe molecules may lead to the comprehension of the surface properties of these catalysts. Thus, in this work, the reaction between methanol and ethyl acetate catalyzed by a series of Mg/La-catalysts was studied using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) coupled to mass spectrometry (QMS) aiming at identify the intermediates and products formed to determine the reaction route. The analysis of X-ray diffraction showed that the precursors are mainly hydrated carbonates of magnesium (Mg/La 1:1 and 9:1) and lanthanum (Mg/La 1:9). The TG profiles and in situ X-ray difratograms obtained during the thermal decomposition of the precursors indicate that these carbonates decompose at 750 ºC or above. Temperature Programmed Desorption analysis carried out with probe molecules, methanol and ethyl acetate, showed a higher amount of methanol adsorbed on the catalyst surface. From the results obtained by DRIFTS-MS a reaction route for the transesterification reaction of methanol and ethyl acetate was proposed. The reaction occurs via adsorption of methanol and ethyl acetate on the catalyst surface. These adsorbed species react forming an adsorbed tetrahedral intermediate which undergoes rearrangement producing ethanol, methyl acetate, acetone and methane. Simultaneously, the methanol adsorbed as a monodentate methoxy specie is dehydrogenated forming formates species that are decomposed in CO2 and H2 |
publishDate |
2015 |
dc.date.available.fl_str_mv |
2015-09-22 |
dc.date.issued.fl_str_mv |
2015-02-27 |
dc.date.accessioned.fl_str_mv |
2021-01-06T19:37:25Z |
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 |
GONÇALVES, Adão de Souza. Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas. 2015. 103 f. Dissertação (Mestrado em Processos Químicos e Meio Ambiente) - Universidade do Estado do Rio de Janeiro, Rio de Janeiro, 2015. |
dc.identifier.uri.fl_str_mv |
http://www.bdtd.uerj.br/handle/1/12031 |
identifier_str_mv |
GONÇALVES, Adão de Souza. Estudo da reação entre o metanol e o acetato de etila em catalisadores Mg/La por espectroscopia no infravermelho acoplada a espectrometria de massas. 2015. 103 f. Dissertação (Mestrado em Processos Químicos e Meio Ambiente) - Universidade do Estado do Rio de Janeiro, Rio de Janeiro, 2015. |
url |
http://www.bdtd.uerj.br/handle/1/12031 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
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openAccess |
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application/pdf |
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Universidade do Estado do Rio de Janeiro |
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Programa de Pós-Graduação em Engenharia Química |
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UERJ |
dc.publisher.country.fl_str_mv |
BR |
dc.publisher.department.fl_str_mv |
Centro de Tecnologia e Ciências::Instituto de Química |
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Universidade do Estado do Rio de Janeiro |
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Biblioteca Digital de Teses e Dissertações da UERJ |
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Biblioteca Digital de Teses e Dissertações da UERJ |
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