Propargylic radicals are an essential component in molecular weight growth kinetics and can react to form polycyclic aromatic hydrocarbons and soot. To establish rate rules for propargylic radicals, a total of 16 H-atom abstraction reactions of three alkynes, namely 1-butyne (1-C₄H₆), 2-butyne (2-C₄H₆), and 3-methyl-1-butyne (C₅H₈), were calculated using high-level quantum chemistry, in which four active radicals including Ḣ, ȮH, ĊH₃, and HȮ₂ were involved. Considering the completeness of the establishment of rate rules, the H-atom abstraction sites have included the primary and secondary site of 1-C₄H₆, primary site of 2-C₄H₆, and tertiary site of C₅H₈. The M06–2X/6–311++G(d,p) level of density function theory was used for the geometry optimization, vibrational frequency, and dihedral scan calculations. Single point energy calculations were carried out at the CCSD/cc-pVXZ (X = T, Q) level of coupled cluster theory. The rate coefficients for all of the abstraction reactions and the thermochemical quantities of 1-C₄H₆, 2-C₄H₆, and C₅H₈ and their corresponding radical products were calculated. The results indicate that H-atom abstraction by ȮH radicals has the fastest reaction rates for all three species. Moreover, abstraction from the tertiary site on C₅H₈ is the fastest, followed by abstraction of secondary hydrogen atoms on 1-C₄H₆ and primary hydrogen atoms on 2-C₄H₆, while abstraction of primary hydrogen atoms on 1-C₄H₆ are the slowest. NUIGMech1.3 (mechanism of version 1.3 proposed by National University of Ireland, Galway) has been updated based on our calculations, and ignition delay times (IDTs) were predicted using the updated mechanism. The predicted IDTs gave better agreement with the experiment data at pressures of 1, 30 and 50 bar. Sensitivity analyses were performed to understand observed model predicted differences at low to intermediate temperatures (700–1000 K) at 10 bar. The results show that the reactions 1-C₄H₆/2-C₄H₆ + HȮ₂ and HȮ₂ + HȮ_{2 <}=> H₂O₂ + O₂ have a significant effect on promoting and inhibiting reactivity, respectively. Further Flux analyses show that the H-atom abstraction from 1-C₄H₆ and 2-C₄H₆ by ȮH radical is a dominant channel in changing branching ratios.

炔丙自由基是分子量增长动力学的重要组成部分，可以反应形成多环芳烃和烟灰。_{为了建立炔丙基的速率规则，三种炔烃（即1-丁炔（1-C 4} H ₆）、2-丁炔（2-C ₄ H ₆）和3-甲基）总共16个H原子夺取反应-1-丁炔(C ₅ H ₈ )是利用高级量子化学计算得到的，其中涉及四个活性自由基，包括Ḣ、ŮH、ĊH ₃和HŮ _{2 。}考虑到速率规则建立的完整性，H原子提取位点包括1-C ₄ H _{6的一级和二级位点、2-C 4} H ₆的一级位点和C ₅ H ₈的三级位点。M06–2X/6–311++ G (d,p) 级密度函数理论用于几何优化、振动频率和二面体扫描计算。在耦合簇理论的 CCSD/cc-pVXZ ( X  =  T , Q) 水平上进行单点能量计算。计算了所有提取反应的速率系数以及1-C ₄ H ₆、2-C ₄ H ₆和C ₅ H _{8及其相应自由基产物的热化学量。}结果表明，对于所有三种物质来说，通过 ŮH 自由基夺取 H 原子的反应速率最快。_{此外，C 5} H ₈上的叔位氢原子的夺取速度最快，其次是1-C ₄ H ₆上的仲氢原子和2-C 4 H 6 上的伯氢原子的夺取，而1-C ₄ H ₆上的伯氢原子的夺取速度次之。 -C ₄ H ₆最慢。NUIGMech1.3（爱尔兰国立大学戈尔韦分校提出的1.3版机制）已根据我们的计算进行了更新，并使用更新后的机制预测了点火延迟时间（IDT）。预测的 IDT 与 1、30 和 50 bar 压力下的实验数据更加吻合。进行灵敏度分析是为了了解在 10 bar 的低温到中温 (700–1000 K) 下观察到的模型预测差异。结果表明反应 1-C ₄ H ₆ /2-C ₄ H ₆  + H? ₂和 H? ₂  + H? _{2 <}=> H ₂ O ₂  + O ₂分别对促进和抑制反应性有显着的作用。进一步的通量分析表明，通过 ŮH 自由基从 1-C ₄ H ₆和 2-C ₄ H ₆中提取 H 原子是改变支化比的主要通道。