用扩展的~(14)C示踪动力学方法解析三类催化剂上丁烯氧化脱氢复杂反应网络

本文详细地介绍了扩展示踪动力学方法(EKIM),并用此法解析了Bi-Mo-P,Sn-P-Li和Fe-Cr-Zn三种丁烯氧化脱氢催化剂上包括丁烯异构化、选择氧化和全氧化等共13个基元反应的复杂反应网络。求得了选择氧化和全氧化的反应级数以及13个速度常数。从这三种催化剂上的不同动力学特征讨论了在Bi-Mo-P和sn-P-Li上选择氧化的控速步骤为第一个氢原子的解离生成烯丙基,在Fe-Cr-Zn上则第一个氢原子的解离不是选择氧化的控速步骤。本文还讨论了选择氧化和异构化在不同催化剂上的可能机理。     

EXTENDED KINETIC ISOTOPE METHOD——ITS APPLICATION TO THE ANALYSIS OF BUTENE OXIDATIVE DEHYDROGENATION REACTION NETWORK OVER THREE CATALYSTS

The "Extended Kinetic Isotope Method" (EKIM) is presented in this paper in detail. The EKIM is applied to the analysis of butene oxidative dehydrogenation reaction network over Bi-Mo-P, Sn-P-Li and ferrite catalysts, including reversible isomerization between the three n-butene isomers, selective oxidation of n-butenes to butadiene, and totaI oxidation of n-butenes and butadiene. The reaction orders of selective and total oxidation reactions, as well as the rate constants of the 13 step reactions, have been estimated. From the results obtained, it is suggested that the rate determining step in the selective oxidation of butenes over the Bi-Mo-P and Sn-P-Li catalysts should be the abstraction of first hydrogen to form allyl intermediate. However, over the ferrite catalyst, the second H-abstraction from allyl intermediate rather than the first one might be the rate determining step. Mechanisms of selective oxidation and isomcrization reactions over the three catalysts are also discussed.