摘要
用动力学模拟的方法探索甲基环戊烷在铂催化剂上开环的反应机理。根据可能的C-C键断裂机理,导出了不同的竞争动力学模型。为了使实验数据与速率方程相符合,在反应机理中必须包含甲基环戊烷的吸附和脱氢两个平衡步骤。用模拟方法判别竞争的动力学模型是困难的,但根据速率方程中参数的物理意义,作者认为C-C键断裂很可能涉及一个氢分子。在生成正己烷和甲基戊烷的反应中没有发现C-C键断裂的活化能有显著差异。
Kinetic modeling was carried out to explore possible reaction mechanism of methylcyclopentane ring opening over a Pt/SiO 2. Different mechanisms were considered for the C-C bound rupture: involving a vacant site, an adsorbed hydrogen, a gaseous hydrogen molecule or a combined form of a H 2 plus a vacant site. Two equilibrium steps, methylcyclopentne adsorption and dehydrogenation, were found to be included in the reaction scheme in order to derive a rate equation consistent with the experimental data, indicating that the effect of the adsorbed methylcyclopentane on the reaction can not be neglected. A discrimination seems difficult between the competitive rate equations by model fitting. However with the significance of the parameters, it is preferred that the C-C bound rupture involves a molecule hydrogen. No significant difference in activation energy of the C-C bound rupture was found between the reactions forming methylpentanes and n-hexane, the value is about 93 kJ/mol. While there is a significant difference in the adsorption heat of methylcyclopentane for these two reactions, it is -111kJ/mol for n-hexane and -22 kJ/mol for methylpentanes.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
1997年第2期147-156,共10页
Chemical Reaction Engineering and Technology
关键词
甲基环戊烷
开环
动力学模拟
铂
催化剂
氧化硅
Methylcyclopentane, Ring opening mechanism, Kinetic modeling, Pt/SiO 2