The ketonization reaction of acetic acid on the (1 0 1) surface of tetragonal zirconia, a process relevant in the catalytic upgrade of cellulosic biomass has been studied by means of DFT+U calculations. The aim was to better understand the role of catalyst pre-reduction. Acetic acid adsorbs strongly on the zirconia surface, and deprotonation to acetate takes place easily. Then, a proton transfer from the methyl group of the acetate ion, CH3COO−, to the surface occurs to form an eno-species, CH2COO2− (intermediate 1). In a parallel step, acetate ions convert into acyl fragments, CH3CO, by oxygen extraction (intermediate 2). Once formed, the acyl intermediate 2 is able to attack the eno-species intermediate 1, to form a β-keto-acid. On stoichiometric zirconia, the formation of the intermediate 1, CH2COO2−, is unfavorable; oxygen vacancies on the reduced surface stabilize the reaction product and strongly reduce the activation energy. Reduced Zr3+ centers are essential to stabilize the acyl intermediate 2. The present work shows at an atomistic level the beneficial role of O vacancies and reduced Zr3+ centers for the ketonization process.
Tosoni, S., & Pacchioni, G. (2016). Acetic acid ketonization on tetragonal zirconia: Role of surface reduction. JOURNAL OF CATALYSIS, 344, 465-473.
|Citazione:||Tosoni, S., & Pacchioni, G. (2016). Acetic acid ketonization on tetragonal zirconia: Role of surface reduction. JOURNAL OF CATALYSIS, 344, 465-473.|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Presenza di un coautore afferente ad Istituzioni straniere:||No|
|Titolo:||Acetic acid ketonization on tetragonal zirconia: Role of surface reduction|
|Autori:||Tosoni, S; Pacchioni, G|
TOSONI, SERGIO PAOLO (Primo)
PACCHIONI, GIANFRANCO (Corresponding)
|Data di pubblicazione:||2016|
|Rivista:||JOURNAL OF CATALYSIS|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.jcat.2016.10.002|
|Appare nelle tipologie:||01 - Articolo su rivista|