HOO·D_(-H)OOH自由基β-断键反应类速率规则计算

Calculation of the rate rules forβ-scission reaction class of HOO:D_(-H)OOH radicals

二氢过氧烯基自由基(HOO·D_(-H)OOH)的β-断键反应类是烯烃低温燃烧反应网络中很重要的一类反应。本文针对该反应类在不同碳原子反应位点的高压极限速率规则开展系统研究。依据HOO·D_(-H)OOH自由基所在碳原子类型的不同,将反应类划分为三个反应子类。单点能计算采用CBS-QB3组合方法,物种几何结构优化和频率分析采用B3LYP/CBSB7方法,高压极限速率常数采用传统过渡态理论计算,并按简单速率规则方法构建了反应类的高压极限速率规则。此外,也探究了HOO·D_(-H)OOH自由基β-断键反应类中反应物构型和取代基大小对反应速率常数的影响规律。本文通过理论计算为该反应类提供了更精确的高压极限速率常数,并为构建可靠的烯烃低温燃烧反应机理提供了精确的反应速率规则。

Theβ-scission reaction of dihydroperoxy-alkenyl-peroxy(HOO·D_(-H)OOH)radicals is one of the important reaction clas-ses in the low temperature combustion reaction network of olefins.In this paper,the high-pressure-limit rate rules of the reaction class at different carbon atom reaction sites are systematically studied,and the reaction class is divided into three reaction subclasses according to the different types of carbon atoms where the HOO·D_(-H)OOH radical resides.The CBS-QB3 method is used for the cal-culation of the single point energy,the geometry optimization and frequency analysis are performed at the B3LYP/CBSB7 level,and the high-pressure-limit rate constants are calculated by the traditional transition state theory,and then these high-pressure-limit rate constants are used to construct the high-pressure-limit rate rules by averaging the rate constants of representative reactions in each subclass.In addition,the effect of reactant configuration and the size of the substituent groups on the rate constants forβ-scission re-action class of HOO·D_(-H)OOH radical are also studied in this paper.This work provides accurate high-pressure-limit rate constants forβ-scission reaction class of HOO·D_(-H)OOH radical through theoretical calculations,which can provide accurate reaction rate rules for the construction of reliable low temperature combustion reaction mechanisms of olefins.