Unraveling the Mechanisms of the Selective Oxidation of Methanol to Formaldehyde in Vanadia Supported on Titania Catalyst
Impacto
Scholar |
Otros documentos de la autoría: González Navarrete, Patricio; Gracia, Lourdes; Calatayud Antonino, Mónica; Andres, Juan
Metadatos
Mostrar el registro completo del ítemcomunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/7013
comunitat-uji-handle3:10234/8638
comunitat-uji-handle4:
INVESTIGACIONEste recurso está restringido
http://dx.doi.org/10.1021/jp911528q |
Metadatos
Título
Unraveling the Mechanisms of the Selective Oxidation of Methanol to Formaldehyde in Vanadia Supported on Titania CatalystFecha de publicación
2010Editor
American Chemical SocietyISSN
1932-7447Tipo de documento
info:eu-repo/semantics/articleVersión de la editorial
http://pubs.acs.org/doi/abs/10.1021/jp911528qVersión
info:eu-repo/semantics/publishedVersionPalabras clave / Materias
Resumen
A computational study based on B3LYP calculations was carried out to investigate the kinetic and mechanistic aspects of the selective oxidation of methanol to formaldehyde using titania-supported vanadate as a catalyst ... [+]
A computational study based on B3LYP calculations was carried out to investigate the kinetic and mechanistic aspects of the selective oxidation of methanol to formaldehyde using titania-supported vanadate as a catalyst model. A complete picture of the possible mechanisms to obtain formaldehyde is given. Statistical mechanics as well as transition state theory (TST) were utilized to determine the rate coefficients and equilibrium constants of the most plausible mechanism. A tetrahedral vanadia containing a methoxy species is found to be the most stable intermediate. The rate-limiting step in the most commonly accepted mechanism is the hydrogen transfer from the tetrahedral methoxy intermediate to the catalyst sites V−O−Ti (46.4 kcal/mol) or V═O (41.0 kcal/mol) via a spin-crossing process. The transition states associated to these steps are biradicaloid. The simultaneous formation of H2 and formaldehyde can be discarded because it proceeds with a higher energetic barrier of 57.0 kcal/mol. The plausibility of a more reactive site involving fivefold coordinated vanadium species along a H-transfer process with a energetic barrier of 20.1 kcal/mol is discussed. Finally, the dependence of the calculated values of energy barriers for the rate-limiting step on the functional used is analyzed. [-]
Derechos de acceso
Copyright 2010 American Chemical Society
http://rightsstatements.org/vocab/InC/1.0/
info:eu-repo/semantics/restrictedAccess
http://rightsstatements.org/vocab/InC/1.0/
info:eu-repo/semantics/restrictedAccess
Aparece en las colecciones
- QFA_Articles [818]