摘要
研究了甲基环戊烷在负载型铂催化剂上的氢解动力学，建立了新的动力学模型．在Ｐｔ／ＳｉＯ２上，两个平行反应（一个生成正己烷，另一个生成甲基戊烷）在甲基环戊烷吸附脱氢过程中存在显著的焓变差异，而Ｃ－Ｃ键断裂活化能则相近．在Ａｌ２Ｏ３负载铂催化剂上，反应的表观活化能仅是在Ｐｔ／ＳｉＯ２上的一半．这是由于Ｃｌ离子的存在，改变了铂的催化性能，导致缺电子铂颗粒的形成，使反应速率的控制步骤从在Ｐｔ／ＳｉＯ２上的Ｃ－Ｃ键断裂变为在Ａｌ２Ｏ３负载铂上的产物加氢脱附．
A rate equation (7) derived in this work was used to characterize methylcyclopentane hydrogenolysis over platinum catalysts. For the two parallel reactions, one producing n hexane and the other forming methylpentanes over Pt/SiO 2, the intrinsic activation energy of the C-C bond rupture is the same and the value is about 93 kJ/mol, while a significant difference was found in enthalpy for the adsorption and dehydrogenation of methylcyclopentane between these two reactions. A low apparent activation energy was observed on Pt/Al 2O 3 and PtRe/Al 2O 3, kinetic simulation shows that the intrinsic activation energy is about 33 kJ/mol. This was attributed to the presence of chlorine on the alumina support, which promotes the formation of electron deficient platinum particles and makes the rate controlling step change from the C-C bond rupture on Pt/SiO 2 to product hydrogenation on Al 2O 3 supported catalysts.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
1997年第4期271-274,共4页
关键词
甲基环戊烷
氢解
铂催化剂
正己烷
甲基戊烷
Methylcyclopentane, Hydrogenolysis, Platinum catalyst, Kinetic simulation, Reaction mechanism
