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Insights into the production of upgraded biofuels using Mg‐loaded mesoporous ZSM‐5 zeolites
Author(s) -
SanahujaParejo Olga,
Veses Alberto,
López José Manuel,
Callén María Soledad,
Solsona Benjamín,
Richards Nia,
Taylor Stuart H.,
García Tomás
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202000787
Subject(s) - deoxygenation , mesoporous material , chemistry , catalysis , decarbonylation , zsm 5 , zeolite , hydrodeoxygenation , aldol condensation , lewis acids and bases , organic chemistry , selectivity
Bio‐oil catalytic upgrading has been performed using mesoporous Mg‐loaded ZSM‐5. The presence of Mg modifies both textural and acidic properties, which do not only depend on the Mg content (1 and 5 wt. %) but also on the Si/Al ratio of the parent zeolite (25 and 40). Mg impregnation over mesoporous acidic zeolites has been shown to be essential for further deoxygenation of the raw bio‐oil. Thus, remarkable deoxygenation rates have been achieved, exceeding 68 % for a 5 wt. % Mg‐loaded ZSM‐5 (Si/Al=25). For this catalyst, decarboxylation reactions at MgO active sites seem to be predominant, promoting the upgrading of phenols towards the formation of phenolic compounds with lower oxygen content. As in the case of acidic mesoporous ZSM‐5, the formation of aromatics for Mg‐loaded mesoporous ZSM‐5 samples could be mainly related to the promotion of decarbonylation reactions of phenolic compounds over Brønsted acidic sites at the external surface. Interestingly, the presence of strong Lewis acidic sites created by the interaction between (Mg 2+ OH − ) + species and extra framework alumina jointly with the remaining Brønsted acidic sites at the external surface could enhance the formation of aromatics through cascade reactions involving ketonization and further aldol condensation and dehydration reactions.