Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination

In the context of vinyl chloride monomer (VCM) production, an oxychlorination catalyst that allows direct VCM formation from gas-derived ethane instead of expensive oil-derived ethene is intensively sought after. A wide range of stable ethane oxychlorination catalysts for this purpose have recently...

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Autores: Scharfe, Matthias, Zichittella, Guido, Kondratenko, Vita A., Kondratenko, Evgenii V., López, Núria, Pérez-Ramírez, Javier
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2019
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2072/450529
Acceso en línea:http://hdl.handle.net/2072/450529
https://doi.org/10.1016/j.jcat.2019.07.021
Access Level:acceso abierto
Palabra clave:54
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spelling Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorinationScharfe, MatthiasZichittella, GuidoKondratenko, Vita A.Kondratenko, Evgenii V.López, NúriaPérez-Ramírez, Javier54In the context of vinyl chloride monomer (VCM) production, an oxychlorination catalyst that allows direct VCM formation from gas-derived ethane instead of expensive oil-derived ethene is intensively sought after. A wide range of stable ethane oxychlorination catalysts for this purpose have recently been reported, yet they mainly yield ethene, while VCM remains a minor by-product. Strikingly, the same catalysts are active in ethene oxychlorination, resulting in selective VCM formation under equivalent reaction conditions. This work reveals the origin of these diverging selectivity patterns by combining quantitative catalytic tests, temporal analysis of products (TAP), and density functional theory (DFT) on iron phosphate. Ethane oxychlorination is found to proceed sequentially through ethyl chloride (EtCl) dehydrochlorination to ethene, while ethene oxychlorination directly yields VCM without formation of the intermediate dichloroethane (EDC) on iron phosphate. Furthermore, by co-feeding ethane in ethene oxychlorination, we demonstrate that the alkane suppresses the formation of VCM in ethene oxychlorination. The reason for this VCM inhibition is found in the hydrocarbon competition for a combination of the active, free and chlorinated iron centers. As ethane activation exhibits half of the barrier of ethene activation, the presence of ethane leads to active site depletion, hindering VCM formation. These observations are extended by ethane co-feeding tests in ethene oxychlorination over a wide range of known oxychlorination catalysts (EuOCl, LaOCl, CeO2, and CuCl2-KCl-LaCl3/γ-Al2O3), and corresponding DFT calculations, indicating that the described phenomenon is material independent. The gathered molecular-level understanding explains the major hurdle of using ethane as feedstock for vinyl chloride production.2019info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersion233 p.application/pdfhttp://hdl.handle.net/2072/450529https://doi.org/10.1016/j.jcat.2019.07.021RECERCAT (Dipòsit de la Recerca de Catalunya)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésETH-04 16-1L'accés als continguts d'aquest document queda condicionat a l'acceptació de les condicions d'ús establertes per la següent llicència Creative Commons:http://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessoai:recercat.cat:2072/4505292026-05-29T05:05:01Z
dc.title.none.fl_str_mv Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
title Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
spellingShingle Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
Scharfe, Matthias
54
title_short Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
title_full Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
title_fullStr Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
title_full_unstemmed Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
title_sort Mechanistic origin of the diverging selectivity patterns in catalyzed ethane and ethene oxychlorination
dc.creator.none.fl_str_mv Scharfe, Matthias
Zichittella, Guido
Kondratenko, Vita A.
Kondratenko, Evgenii V.
López, Núria
Pérez-Ramírez, Javier
author Scharfe, Matthias
author_facet Scharfe, Matthias
Zichittella, Guido
Kondratenko, Vita A.
Kondratenko, Evgenii V.
López, Núria
Pérez-Ramírez, Javier
author_role author
author2 Zichittella, Guido
Kondratenko, Vita A.
Kondratenko, Evgenii V.
López, Núria
Pérez-Ramírez, Javier
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv 54
topic 54
description In the context of vinyl chloride monomer (VCM) production, an oxychlorination catalyst that allows direct VCM formation from gas-derived ethane instead of expensive oil-derived ethene is intensively sought after. A wide range of stable ethane oxychlorination catalysts for this purpose have recently been reported, yet they mainly yield ethene, while VCM remains a minor by-product. Strikingly, the same catalysts are active in ethene oxychlorination, resulting in selective VCM formation under equivalent reaction conditions. This work reveals the origin of these diverging selectivity patterns by combining quantitative catalytic tests, temporal analysis of products (TAP), and density functional theory (DFT) on iron phosphate. Ethane oxychlorination is found to proceed sequentially through ethyl chloride (EtCl) dehydrochlorination to ethene, while ethene oxychlorination directly yields VCM without formation of the intermediate dichloroethane (EDC) on iron phosphate. Furthermore, by co-feeding ethane in ethene oxychlorination, we demonstrate that the alkane suppresses the formation of VCM in ethene oxychlorination. The reason for this VCM inhibition is found in the hydrocarbon competition for a combination of the active, free and chlorinated iron centers. As ethane activation exhibits half of the barrier of ethene activation, the presence of ethane leads to active site depletion, hindering VCM formation. These observations are extended by ethane co-feeding tests in ethene oxychlorination over a wide range of known oxychlorination catalysts (EuOCl, LaOCl, CeO2, and CuCl2-KCl-LaCl3/γ-Al2O3), and corresponding DFT calculations, indicating that the described phenomenon is material independent. The gathered molecular-level understanding explains the major hurdle of using ethane as feedstock for vinyl chloride production.
publishDate 2019
dc.date.none.fl_str_mv 2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/2072/450529
https://doi.org/10.1016/j.jcat.2019.07.021
url http://hdl.handle.net/2072/450529
https://doi.org/10.1016/j.jcat.2019.07.021
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv ETH-04 16-1
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 233 p.
application/pdf
dc.source.none.fl_str_mv RECERCAT (Dipòsit de la Recerca de Catalunya)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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