Title of article :
Methylation of benzene by methanol: Single-site kinetics over H-ZSM-5 and H-beta zeolite catalysts
Author/Authors :
Jeroen Van der Mynsbrugge، نويسنده , , Melina Visur، نويسنده , , Unni Olsbye، نويسنده , , Pablo Beato، نويسنده , , Morten Bj?rgen، نويسنده , , Veronique Van Speybroeck، نويسنده , , Stian Svelle، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2012
Pages :
12
From page :
201
To page :
212
Abstract :
Benzene methylation by methanol is studied on acidic zeolites H-ZSM-5 (MFI) and H-beta (BEA) to investigate the influence of the catalyst topology on the reaction rate. Experimental kinetic measurements at 350 °C using extremely high feed rates to suppress side reactions show that methylation occurs considerably faster on H-ZSM-5 than on H-beta. Theoretical rate constants, obtained from first-principles simulations on extended zeolite clusters, reproduce a higher methylation rate on H-ZSM-5 and provide additional insight into the various molecular effects that contribute to the overall differences between the two catalysts. The calculations indicate this higher methylation rate is primarily due to an optimal confinement of the reacting species in the medium pore material. Co-adsorption of methanol and benzene is energetically favored in H-ZSM-5 compared with H-beta, to the extent that the stabilizing host–guest interactions outweigh the greater entropy loss upon benzene adsorption in H-ZSM-5 vs. in H-beta.
Keywords :
Ziegler–Natta catalysts , Oxidative addition , Titanium valence , Ethylene polymerization
Journal title :
Journal of Catalysis
Serial Year :
2012
Journal title :
Journal of Catalysis
Record number :
1223646
Link To Document :
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