Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production

Sustainable technologies for the valorisation of the burgeoning amounts of glycerol (GLY) obtained as waste in the production of biodiesel are increasingly sought after. Its conversion into lactic acid (LA) is appealing due to the versatility of this platform chemical and its high added value. Here,...

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Autores: Lari, G. M., García-Muelas, R., Mondelli, C., López, Núria, Pérez-Ramírez, J.
Tipo de documento: artigo
Estado:Versión aceptada para publicación
Data de publicação:2016
País:España
Recursos:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositório:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2072/358880
Acesso em linha:http://hdl.handle.net/2072/358880
https://doi.org/10.1039/C6GC00894A
Access Level:Acceso aberto
Palavra-chave:54
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spelling Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid productionLari, G. M.García-Muelas, R.Mondelli, C.López, NúriaPérez-Ramírez, J.54Sustainable technologies for the valorisation of the burgeoning amounts of glycerol (GLY) obtained as waste in the production of biodiesel are increasingly sought after. Its conversion into lactic acid (LA) is appealing due to the versatility of this platform chemical and its high added value. Here, we introduce Ag-based catalysts for the oxidehydration of GLY to pyruvaldehyde (PAl) and demonstrate the superiority of this compound in comparison to dihydroxyacetone (DHA) as the intermediate of an alternative two-step GLY-to-LA process. Evaluation of various metals and carriers identified Ag/Al2O3 as the best per- former for PAl production. This was rationalised based on the optimal redox potential of the metal and the high concentration of Lewis-acid sites and the limited Brønsted acidity of the support. At 623 K and O2/GLY = 0.5, a PAl yield of 80% was attained, which remained stable for 24 h. Characterisation of the used catalyst indi- cated that the surface of the silver nanoparticles was partially oxidised upon reaction. Density functional theory (DFT) modelling revealed that the oxidation of acetol obtained from GLY after the initial dehydration step is kinetically and thermodynamically favoured on a partially oxidised silver surface (AgOx/Ag) compared to met- allic (Ag) or fully oxidic (Ag2O) ones. Finally, we show that PAl can be isomerised into LA and methyl lactate over Sn-containing zeolites with the same rates as DHA but at a 40 K lower temperature (343 vs. 383 K). This not only allows for energy savings but also for a remarkably increased catalyst stability.2016info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersion4682 p.application/pdfhttp://hdl.handle.net/2072/358880https://doi.org/10.1039/C6GC00894ARECERCAT (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)InglésL'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:2072/3588802026-05-29T05:05:01Z
dc.title.none.fl_str_mv Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
title Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
spellingShingle Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
Lari, G. M.
54
title_short Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
title_full Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
title_fullStr Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
title_full_unstemmed Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
title_sort Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production
dc.creator.none.fl_str_mv Lari, G. M.
García-Muelas, R.
Mondelli, C.
López, Núria
Pérez-Ramírez, J.
author Lari, G. M.
author_facet Lari, G. M.
García-Muelas, R.
Mondelli, C.
López, Núria
Pérez-Ramírez, J.
author_role author
author2 García-Muelas, R.
Mondelli, C.
López, Núria
Pérez-Ramírez, J.
author2_role author
author
author
author
dc.subject.none.fl_str_mv 54
topic 54
description Sustainable technologies for the valorisation of the burgeoning amounts of glycerol (GLY) obtained as waste in the production of biodiesel are increasingly sought after. Its conversion into lactic acid (LA) is appealing due to the versatility of this platform chemical and its high added value. Here, we introduce Ag-based catalysts for the oxidehydration of GLY to pyruvaldehyde (PAl) and demonstrate the superiority of this compound in comparison to dihydroxyacetone (DHA) as the intermediate of an alternative two-step GLY-to-LA process. Evaluation of various metals and carriers identified Ag/Al2O3 as the best per- former for PAl production. This was rationalised based on the optimal redox potential of the metal and the high concentration of Lewis-acid sites and the limited Brønsted acidity of the support. At 623 K and O2/GLY = 0.5, a PAl yield of 80% was attained, which remained stable for 24 h. Characterisation of the used catalyst indi- cated that the surface of the silver nanoparticles was partially oxidised upon reaction. Density functional theory (DFT) modelling revealed that the oxidation of acetol obtained from GLY after the initial dehydration step is kinetically and thermodynamically favoured on a partially oxidised silver surface (AgOx/Ag) compared to met- allic (Ag) or fully oxidic (Ag2O) ones. Finally, we show that PAl can be isomerised into LA and methyl lactate over Sn-containing zeolites with the same rates as DHA but at a 40 K lower temperature (343 vs. 383 K). This not only allows for energy savings but also for a remarkably increased catalyst stability.
publishDate 2016
dc.date.none.fl_str_mv 2016
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/2072/358880
https://doi.org/10.1039/C6GC00894A
url http://hdl.handle.net/2072/358880
https://doi.org/10.1039/C6GC00894A
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 4682 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
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