Influence of functional groups on the oxidation of aromatic structures

关于全球能源需求的持续增长，世纪的主要挑战是减少化石燃料燃烧。改进燃烧系统和用可持续能源载体取代传统燃料有助于实现这一目标。在这种情况下，生物基辛烷值改进剂，即含氧芳烃，可以发挥重要作用。这些化合物可以由不可食用的木质素生产，并且它们的物理化学性质使它们成为具有改进的抗爆震行为的理想燃料混合组分。在该项目的第一阶段，进行了最常见的含氧芳烃的点火延迟时间（IDT）。通过实验和动力学模拟研究了苯甲醚的燃烧特性。通过测定含氧芳烃/正戊烷混合物的着火延迟时间，考察了一系列含氧芳烃物种的辛烷值提升性能。这些研究揭示了苯氧基自由基和苯甲醛在大多数含氧芳烃燃烧过程中的重要性。然而，关于这些组成部分的详细研究很少，因此将成为项目第二阶段的重点。将在点火延迟期间对反应苯酚和苯甲醛混合物进行高压气体取样，给出燃烧稳定中间体的摩尔分数分布。结合点火延迟时间的形态实验将指导动力学建模并用作验证目标。最后，该模型将用于更深入地了解关键中间体苯氧基自由基和苯甲醛的燃烧行为，这将影响对芳香族结构氧化方案的理解。此外，不同取代基的芳环上的反应活性的定位效果将进行实验研究。

In regards of a permanent increase in the global energy demand, a major challenge of the century is the reduction in fossil fuel combustion. Improving combustion systems and replacing conventional fuels by sustainable energy carriers can help in achieving this goal. In this context bio-based octane improvers, i.e. oxygenated aromatics, can play an important role. These compounds can be produced from uneatable lignin and their physico-chemical properties make them ideal fuel blending components with improved anti-knock behavior. In the first phase of the project, the ignition delay times (IDTs) of the most common oxy-aromatics were performed. The combustion behavior of anisole was investigated through an extended experimental and kinetic modeling study. The octane booster properties of series of oxy-aromatic species were examined by the measurement of the ignition delay time of oxy-aromatic/n-pentane blends. These studies revealed the importance of the phenoxy radical and benzaldehyde in the combustion process of the majority of oxy-aromatics. However, detailed studies on these components are scarce and will be consequently in the focus of the second phase of the project. High-pressure gas sampling of reacting phenol and benzaldehyde mixtures during the ignition delay will be performed, giving mole fraction profiles of the stable intermediates of combustion. The speciation experiments coupled with ignition delay times will guide the kinetic modeling and be used as validation targets. In the end, the model will be used to get a deeper insight into the combustion behavior of the crucial intermediates phenoxy radical and benzaldehyde which will impact the understanding of the oxidation scheme of aromatic structures in general. In addition, the positioning effect of different substituents on the aromatic ring on the reactivity will be examined experimentally.