Exploring the rehydroxylation reaction of pyrophyllite by ab initio molecular dynamics.
J Phys Chem B
; 114(22): 7593-601, 2010 Jun 10.
Article
en En
| MEDLINE
| ID: mdl-20469939
We have investigated the process of rehydroxylation of pyrophyllite as a limiting factor to the dehydroxylation upon thermal treatment. Car-Parrinello molecular dynamics simulations based on density functional theory have been used along with the metadynamics algorithm. Two possible rehydroxylation mechanisms reaction have been characterized, related to two possible intermediate structures along the rehydroxylation paths, and both involve the interaction of the apical oxygen atoms. At high temperature, the rehydroxylation reaction is highly competitive (free energy barrier (DeltaF) = 1.5 kcal/mol) and inhibits the progress of the dehydroxylation reaction (DeltaF = 40 kcal/mol). In addition to the rehydroxylation of the dehydroxylated structure, the water molecule supports the interconversion of the cross and on-site intermediates as well. Thus, rehydroxylation and interconversion among intermediates can justify the wide range of transformations as a function of the temperature observed experimentally.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2010
Tipo del documento:
Article
País de afiliación:
España
Pais de publicación:
Estados Unidos