催化反应中休眠期与诱导期之区别

许多化学反应中都存在一个被定义为"诱导期"的起始反应速率较低的阶段,例如一些自由基反应、放热反应和催化反应。与之相比,在极少数的催化反应中研究者观察到一个反应速率始终为零的特殊阶段,在这个阶段之后反应自发开始。这两种阶段形成的原因与反应的机理尤其是催化剂的活化和失活有关。然而,这两个具有明显不同特征的阶段往往被混淆。本文通过所选取的一些代表性的催化反应分别介绍了"诱导期"和"休眠期"的动力学特征,讨论了两者之间的区别。期待这些隐藏在稳态催化循环之前的阶段能够得到更多的关注,这将有利于研究人员深度理解有机化学反应中的前催化循环和详细的反应机理。

The Differences between Dormant Period and Induction Period in Catalytic Reactions

An initial slow phase which is nominated as induction period usually occurs in many chemical reactions such as some radical reactions, exothermic reactions and catalytic reactions. In contrast, a special phase during which the reaction rate is zero and after which the reaction starts spontaneously, has rarely been observed in a few catalytic reactions. The formation of these two kinds of periods is related to the mechanism of the reaction especially to the catalyst activation or deactivation. However, the two periods have been confused and their obvious distinctions have been neglected in the past. In this perspective, typical kinetic features of induction period and dormant period are demonstrated with selected catalytic reactions, and the differences between them are discussed. In-depth understanding of the pre-catalytic cycle and detailed mechanism of organic reactions are expected if more attentions would be paid to these hidden processes in front of the steady state catalytic cycle.