Rate-limiting step for alkane dehydrogenation in zeolite H-ZSM-5.

Zygmunt, S. A. ; Bootz, B. L. ; Miller, A. W. ; Curtiss, L. A. ; Iton, L. E.

Technical Information Center Oak Ridge Tennessee

关键词: Dehydrogenation;    Chemical reaction kinetics;    Zeolites;    Activation energy;    Butane;   

RP-ID  :  DE2001768593

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We have carried out a computational study of protolytic cracking, dehydrogenation, and H/D exchange of ethane, propane, and butane using a cluster model of H-ZSM-5. Our previous work has demonstrated that quantum-chemical techniques can give quantitatively accurate activation energies for alkane cracking in zeolites (1). Experimental kinetic studies have shown that the apparent activation energies for cracking and H/D exchange decrease with n-alkane chain length, while for dehydrogenation the energies increase (2,3). Our goal is to study the dependence of the activation energy on the alkane chain length in these reactions and to understand why the dehydrogenation reaction behaves so differently.