Theoretical study of the Ga/SAPO-11 catalyst: Extra-framework gallium species and n-butane transformation

Abstract:

Calculations to study the interaction of Ga⁺, [GaO]⁺ and Ga<inf>2</inf>O with a Brönsted acid site of a SAPO-11 silicoaluminophospates were carried out using the semiempirical MSINDO approach. The SAPO-11 structure was modeled by a ring of 10 tetrahedrons and 3 rings of 10 tetrahedrons system. The calculations show that the formation of [HGaOH] ⁺ and [GaH<inf>2</inf>]⁺ species by reduction with H <inf>2</inf> are thermodynamically favored. The transformation of [HGaOH] ⁺ into Ga⁺ and water is highly endothermic. The Ga <inf>2</inf>O react with the Brönsted acid site to produce anchored species, which can be reduced by molecular hydrogen to give [Ga(GaH)(OH)] and [GaOGaH<inf>2</inf>]. The Ga⁺ and Ga<inf>2</inf>O reactions with n-butane to produces butenes are all endothermic. © 2005 Elsevier B.V. All rights reserved.

Año de publicación:

2005

Keywords:

• Gallium hydrides
• calculations
• MSINDO
• GA
• GaH 2
• SAPO-11
• Ga O 2
• Ga2O

Fuente:

scopus