TOWARDS UNDERSTANDING THE ROLE OF DIFFERENT METAL OXIDES IN THE ACETONE HYDRODEOXYGENATION REACTION

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  • Presentation type: Oral
  • Track: 3.Conversion of Biomass and Derived Molecules
  • Keywords: biomass conversion; heterogeneous catalysis; hydrodeoxygenation; metal oxides;
  • 1 Universidade Estadual de Campinas
  • 2 Laboratório Nacional de Luz Síncrotron

TOWARDS UNDERSTANDING THE ROLE OF DIFFERENT METAL OXIDES IN THE ACETONE HYDRODEOXYGENATION REACTION

Guilherme Strapasson

Universidade Estadual de Campinas

Abstract

The hydrodeoxygenation reaction (HDO) is an important route for upgrading biomass-derived compounds. Aiming to understand how reducible oxide participates in the reaction mechanism, different oxides (TiO2, CeO2, Fe2O3, and Co3O4) were employed in the gas-phase HDO of acetone, a representative molecule for ketone-containing biomass derivatives. According to the products obtained, a multisite reaction network was observed, in which metallic, Brønsted/Lewis acidic, and oxygen vacancy sites acted. For TiO2 and CeO2, low deoxygenation degrees (< 30 %) and high selectivity toward condensation products (> 70 %) were achieved at 400 °C, expressing the dominance of acid sites, mostly of the Lewis nature. The presence of C3 products, however, pointed out to the importance of the oxygen vacancies in a direct deoxygenation route in these oxides. For Fe2O3, and Co3O4, in which the reducing reaction atmosphere induces the coexistence of metallic and oxidized phases, metal sites also come into play, favoring mostly hydrogenation and C-C hydrogenolysis pathways. For Co3O4, the C-C hydrogenolysis leads to methane as the major product (67%) already at 250°C, whereas for Fe2O3, a compromise between the formation of acid-, metal- and oxygen vacancy-catalyzed products was achieved, being C3 products slightly favored (40.5 %).

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Author

Guilherme Strapasson

Olá, José Lucas! Muito obrigado!! A coexistência das diferentes fases de cobalto no nosso melhor catalisador gera diferentes sítios catalíticos (metálicos e de vacância de oxigênio), fazendo com que diferentes caminhos reacionais possam ocorrem. Sítios de cobalto metálico tendem a levar à hidrogenólise das ligações C-C, tendo como produto majoritário metano. No entanto, quando há a coexistência de espécies de cobalto oxidado (+2 e +3), há uma diminuição da hidrogenólise C-C e um aumento da hidrogenólise C-O, devido a sítios de vacância de oxigênio. Além disso, a coexistência dessas diferentes fases de cobalto pode levar à mudanças na oxofilicidade do catalisador, favorecendo a ativação das ligações C-O.

Caso queira entender em mais detalhe os possíveis caminhos reacionais em função das diferentes espécies de cobalto, pode acessar o artigo pelo seguinte link: https://www.sciencedirect.com/science/article/pii/S2468823122005107

E qualquer dúvida adicional, estou à disposição!

José Lucas Vieira

Maravilha, Guilherme... Extremamente interessante! Parabéns novamente pelo trabalho.