Abstract Ketohydroperoxides (KHPs) are oxygenated hydrocarbons that include carbonyl and peroxide functional groups. The decomposition pathways of KHPs are chain branching pathways in low temperature chemistry of alkanes and oxygenated biofuels, which makes KHPs critical intermediates in ignition processes in advanced combustion engines. In this work, KHP formation was investigated in the low temperature oxidation of a primary reference fuel (PRF 70), a binary mixture of 30 vol% n-heptane and 70 vol% iso-octane to represent a low octane number gasoline surrogate. Species were detected and measured in a jet-stirred reactor (JSR), coupled with time-of-flight molecular beam mass spectrometer using synchrotron vacuum-ultraviolet radiation as photon ionization source (SVUV-PI-TOF-MBMS) which provides in-situ measurement of unstable KHPs. Simultaneous KHPs production from higher reactivity n-heptane and lower reactivity iso-octane at similar temperatures was observed. Kinetic modeling was used to study the reactivity across a wide temperature range and to examine KHP formation chemistry. Specifically, signals vs. temperature profiles in experiments and mole fraction vs. temperature profiles in simulations, were compared to indicate the most possible saturated KHP isomers. Possible formation pathways for olefinic KHPs and di-olefinic KHPs are discussed. This work reports simultaneous formation of KHPs from two fuel molecules in a gasoline surrogate mixture, discusses important reaction pathways in low temperature oxidation, and explains simultaneous KHP production in n-heptane/iso-octane mixtures, i.e., low temperature oxidation of less reactive iso-octane is initiated by OH radicals produced from high reactivity n-heptane oxidation.

中文翻译：

---

通过低温氧化汽油主要参考燃料混合物同时生产酮氢过氧化物

摘要 酮氢过氧化物 (KHPs) 是包含羰基和过氧化物官能团的含氧烃。KHPs 的分解途径是烷烃和含氧生物燃料低温化学中的支链途径，这使得 KHPs 成为先进内燃机点火过程中的关键中间体。在这项工作中，研究了在初级参考燃料 (PRF 70) 的低温氧化中形成 KHP，这是一种由 30 vol% 正庚烷和 70 vol% 异辛烷组成的二元混合物，代表低辛烷值汽油替代品。在喷射搅拌反应器 (JSR) 中检测和测量物种，并结合使用同步加速器真空紫外辐射作为光子电离源 (SVUV-PI-TOF-MBMS) 的飞行时间分子束质谱仪，提供原位不稳定 KHP 的测量。观察到在相似温度下由反应性较高的正庚烷和反应性较低的异辛烷同时产生 KHP。动力学模型用于研究宽温度范围内的反应性并检查 KHP 形成化学。具体而言，将实验中的信号与温度曲线和模拟中的摩尔分数与温度曲线进行比较，以表明最可能的饱和 KHP 异构体。讨论了烯烃 KHP 和二烯烃 KHP 的可能形成途径。这项工作报告了由汽油替代混合物中的两个燃料分子同时形成 KHP，讨论了低温氧化中的重要反应途径，并解释了在正庚烷/异辛烷混合物中同时产生 KHP，即，