Benzene and toluene were pyrolyzed under highly argon-diluted conditions at a nominal pressure of 20 bar in a single-pulse shock tube coupled to gas chromatography/gas chromatography–mass spectrometry (GC/GC–MS) diagnostics. Concentration evolutions of polycyclic aromatic hydrocarbon (PAH) intermediates were measured in a temperature range of 1100–1800 K by analyzing the post-shock gas mixtures. Different PAH speciation behaviors, regarding types, concentrations and formation temperature windows, were observed in the two reaction systems. A kinetic model was proposed to predict and interpret the measurements. Through a combination of experimental and modeling efforts, PAH formation patterns from species pools of benzene and toluene pyrolysis were illustrated. In both cases, channels leading to PAHs basically originate from the respective fuel radicals, phenyl and benzyl. Due to the higher thermal stability of benzene, the production of phenyl, and thus most PAH species, occur in higher temperature windows, in comparison to the case of toluene. In benzene pyrolysis, benzyne participates in the formation of crucial PAH species such as naphthalene and acenaphthylene. Phenyl self-recombination takes considerable carbon flux into biphenyl, which serves as an important intermediate leading to acenaphthylene through hydrogen loss and ring closure. The resonantly-stabilized benzyl is abundant in toluene pyrolysis, and its decomposition further produces other resonantly-stabilized radicals such as fulvenallenyl and propargyl. Barrierless addition reactions among these radicals are found to be important sources of PAHs. Fuel-specific pathways have pronounced effects on PAH speciation behaviors, particularly at lower temperatures where fuel depletion is not completed within the reaction time of 4.0 ms. Contributions from the commonly existing Hydrogen-Abstraction-Carbon-Addition (HACA) routes increase with the temperature in both cases.

苯和甲苯在高度氩气稀释的条件下，在与气相色谱/气相色谱-质谱（GC / GC-MS）诊断联用的单脉冲激波管中，在标称压力为20 bar的条件下热解。通过分析震后气体混合物，在1100-1800 K的温度范围内测量了多环芳烃（PAH）中间体的浓度变化。在两个反应系统中，观察到关于类型，浓度和形成温度窗口的不同PAH形态行为。提出了动力学模型来预测和解释测量结果。通过实验和建模工作的结合，说明了苯和甲苯热解物种库中PAH的形成方式。在这两种情况下 导致PAHs的通道基本上源自各自的燃料自由基，苯基和苄基。由于苯具有更高的热稳定性，与甲苯相比，苯的生成以及大多数PAH物种的生成都在较高的温度范围内。在苯的热解中，苯并炔参与重要的PAH物种的形成，例如萘和。苯基的自重组使相当大的碳通量进入联苯，联苯是通过氢损失和闭环导致leading的重要中间体。共振稳定的苄基在甲苯热解中含量很高，并且其分解进一步产生其他共振稳定的基团，例如富维烯基和炔丙基。发现这些自由基之间的无障碍加成反应是PAHs的重要来源。特定于燃料的途径对PAH的形态行为具有显着影响，尤其是在4.0 ms反应时间内未完成燃料消耗的较低温度下。在两种情况下，通常存在的氢提取碳-加成（HACA）路线的贡献都随温度而增加。