To investigate the role of five-membered rings in the growth of polycyclic aromatic hydrocarbons (PAHs) in flames, the conversion of acenaphthylene to pyrene with substituted phenalene as intermediate is studied through quantum calculations using CBS-QB3 composite method. Two pathways are considered, where one initiates with H-abstraction from the five membered ring on acenaphthylene, while the other initiates with H-addition on it. Both the pathways are then followed by subsequent C₂H₂ addition reactions on the radical sites. With the first C₂H₂ addition, a substituted phenalene-type species is formed, which undergoes another C₂H₂ addition reaction to lead to pyrene formation. The reaction kinetics are calculated using transition state theory, and the new reactions are added to a detailed hydrocarbon mechanism to test their effect on the profiles of pyrene and other PAHs. Among the H-abstraction-C₂H₂-addition (HACA)-type mechanisms for pyrene formation, the proposed reactions have a minor contribution in pyrene formation as they mainly form 1-ethynyl-acenaphthylene and phenanthrene. Through mechanism analysis, the reactions primarily responsible for pyrene formation are highlighted that require further investigation.

为研究五元环在火焰中多环芳烃 (PAHs) 生长中的作用，采用 CBS-QB3 复合方法通过量子计算研究苊烯转化为芘的过程，其中以取代苯酚为中间体。考虑了两种途径，一种以苊上五元环的 H-抽象开始，而另一种以 H-加成开始。然后在这两种途径之后在自由基位点上进行后续的 C ₂ H ₂加成反应。随着第一次 C ₂ H ₂的添加，形成了一个取代的苯烯类物质，它经历了另一个 C ₂ H ₂加成反应生成芘。使用过渡态理论计算反应动力学，并将新反应添加到详细的烃机理中，以测试它们对芘和其他 PAHs 分布的影响。在用于芘形成的H-抽象-C ₂ H ₂加成（HACA）型机制中，所提出的反应对芘形成的贡献很小，因为它们主要形成1-乙炔基-苊和菲。通过机理分析，突出了主要负责芘形成的反应，需要进一步研究。