【摘要】 基于密度泛函理论（DFT）和过渡态理论（TST），利用苯基加成环化（PAC）机制，对内燃机缸内的苯并芘生成历程进行探索．结果表明：蒽自由边和锯齿边与苯基的入口反应均表现出无能垒、高放热和速率快的特点．分析各路径限速步速率可知，蒽自由边C1位点比锯齿边C2位更易生成苯并芘，最优反应路径限速步能垒仅为176.2 k J/mol，反应速率为3.7×10⁹s^-1．锯齿边C2位的两条主路径限速步为五元环转化成六元环的异构化反应，能垒分别高达417.2 k J/mol和421.7 k J/mol，反应速率分别为8.7×10⁴s^-1和5.8×10⁴s^-1．此外，芳香环上H迁移反应的难度高于脂肪链上H迁移．该研究提供了苯并芘的PAC生成机理，这为构建苯并芘的化学动力学模型提供理论依据，对预测内燃机缸内的苯并芘生成具有重要意义．更多还原

【Abstract】 Based on density functional theory（DFT） and transition state theory（TST）,the formation process of benzopyrene in the cylinder of internal combustion engines was investigated by phenyl-addition cyclization（PAC）mechanism.The results show that the entrance reactions of both anthracene free edge and sawtooth edge with phenyl exhibit barrierless,high exotherm and fast rate.By analyzing the rate-limiting step rates of each pathway,it is found that the anthracene free edge C1 site is more likely to generate benzopyrene than the sawtooth edge C2site,and the optimal reaction pathway rate-limiting step energy barrier is only 176.2 k J/mol with a reaction rate of3.7×10⁹s^-1.The rate-limiting step of the two main paths at the C2 position of the sawtooth edge is the isomerization of the five-membered ring into the six-membered ring.The energy barrier is up to 417.2 k J/mol and 421.7 k J/mol,and the reaction rates are 8.7×10⁴s^-1 and 5.8×10⁴s^-1,respectively.In addition,the H migration reaction on the aromatic ring is more difficult than on the aliphatic chain.This study provides the mechanism of PAC generation of benzopyrene,which gives a theoretical basis for the construction of chemical kinetics model of benzopyrene and is important for predicting the generation of benzopyrene in the cylinder of internal combustion engines.更多还原