Alkylbenzenes are major aromatic constituents of real transportation fuels and important surrogate components. In this study, the structural impact of nine alkylbenzenes on their ignition characteristics is experimentally and computationally investigated with particular emphasis on the blending effect with significantly more reactive normal alkanes. Experimental comparisons of mono-alkylbenzenes (toluene, ethylbenzene, n-propylbenzene, iso-propylbenzene) from a modified CFR engine showed that the difference in pure alkylbenzene reactivity significantly diminished when blended with n-heptane, as the strength of the radical scavenging effect of all three alkylbenzenes is similar. Among C₈H₁₀ isomers, the reactivity of pure ethylbenzene and o-xylene and their blends with n-heptane showed a complex competing effect between the difference in CH bond energy and the existence of intermediate/low-temperature chemistry caused by adjacent methyl pairs. A similar structural impact was also observed for C₉H₁₂ isomers and their blends with n-heptane, while the influence of CH bond energy was more noticeable than C₈H₁₀ molecules. Kinetic simulations of the alkylbenzene/n-heptane blends highlighted the effect caused by adjacent methyl pairs that is referred to as the “ortho effect”. Analysis of ethylbenzene and o-xylene showed that o-xylene's intermediate/low-temperature pathways initiated by benzylperoxy radical – benzylhydroperoxide isomerization (RO2 – QOOH) produce additional active radicals such as OH and CH₂O, which accelerates the oxidation chemistry of more reactive n-heptane. This study provides knowledge on the blending effect of alkylbenzene compounds with n-heptane on their ignition characteristics that is useful to develop surrogates that can better mimic the reactivity of real fuels.

烷基苯是实际运输燃料的主要芳族成分，也是重要的替代组分。在这项研究中，通过实验和计算研究了九种烷基苯对它们的着火特性的结构影响，其中特别强调了与反应性更高的正构烷烃的共混效果。来自改性CFR发动机的单烷基苯（甲苯，乙苯，正丙基苯，异丙基苯）的实验比较表明，与正庚烷混合时，纯烷基苯反应性的差异显着减小，因为所有三个烷基苯都是相似的。在C ₈ H _10中异构体，纯乙苯和邻二甲苯及其与正庚烷的共混物的反应性表明，在C H键能差异和相邻甲基对引起的中/低温化学反应之间，存在复杂的竞争作用。对于C ₉ H ₁₂异构体及其与正庚烷的共混物，也观察到了类似的结构影响，而C H键能的影响比C ₈ H ₁₀更为明显。分子。烷基苯/正庚烷混合物的动力学模拟突出了由相邻甲基对引起的效应，称为“邻位效应”。对乙苯和邻二甲苯的分析表明，由苄基过氧自由基–苄基氢过氧化物异构化（RO2 – QOOH）引发的邻二甲苯的中间/低温途径会产生额外的活性自由基，例如OH和CH ₂ O，从而加速了更具反应性的氧化化学反应。正庚烷。这项研究提供了有关烷基苯化合物与正庚烷对它们的着火特性的共混作用的知识，可用于开发可以更好地模拟真实燃料反应性的替代物。