Structure–activity relationships and reaction mechanisms for future fuel components: Dialkyl ethers, oxymethylene ethers, and furanes

直链和环醚作为可由生物质或电化学法生产的燃料组分，将在未来的燃烧系统中发挥重要作用。尽管它们很重要，但对它们的分解和燃烧化学的了解还不够。在这个项目中，这一重要的知识差距应该通过在与燃烧相关的条件下，即在1000K以上的温度下对二烷基醚、甲醛甲醚(OMES)和呋喃进行实验和理论化学动力学研究来弥合。对于燃烧过程的详细建模，氢提取反应是一类至关重要的反应。因此，本项目的第一部分旨在通过激波管实验，结合光谱技术和从头算过渡态理论(TST)的计算，确定一系列选定的直链、支链和环醚的OH自由基和H原子提取H的速率系数。根据基团加和性的概念，实验和理论结果的结合旨在推导出能够计算所有醚类化合物的H-抽提速率系数的速率规则。在该项目的第二部分，将在激波管实验中研究这类物质的代表性分子的热解。一方面，将进行激波管实验与气相色谱(GC/MS)和飞行时间质谱仪(TOF-MS)相结合，另一方面，将进行流动反应器实验与GC/MS相结合，以确定热解过程中反应产物的组成。结果，可以确定初始单分子反应所需的动力学信息，并可以识别重要的二次反应。借助实验结果和麻省理工学院开发的反应机理生成器(RMG)程序，正在开发和优化反应模型。在这个项目中，杜伊斯堡-埃森大学燃烧与气体动力学研究所(IVG)和燃烧技术研究所(DLR Stuttgart)的互补专业知识将结合在一起。氢自由基提取氢的实验工作、质谱学的时间分辨测量、流动反应器测量和从头计算被分配给IVG，而同位素标记组分中H原子提取氢的实验、用GC/MS进行激波管实验以及反应机理的开发被分配给德国航天中心斯图加特。

Linear and cyclic ethers, as fuel components that can be produced from biomass or electrochemically, will play an important role in future combustion systems. Despite their importance, the understanding of their decomposition and combustion chemistry is insufficient. This important knowledge gap should be closed in this project by experimental and theoretical chemical kinetics investigations of dialkyl ethers, oxymethylene ethers (OMEs), and furanes under combustion-relevant conditions, i.e. at temperatures above 1000 K.For detailed modeling of combustion processes, hydrogen abstraction reactions represent a class of crucial importance. Therefore, the first part of this project aims at determining rate coefficients for H abstractions by OH radicals and H atoms for a series of selected linear, branched, and cyclic ethers by shock-tube experiments in combination with spectrometric techniques and interpretations by ab initio transition state theory (TST) calculations. Following the concept of group additivity, the combination of experimental and theoretical results aims to derive rate rules that enable the calculation of H-abstraction rate coefficients for all ether compounds. In the second part of the project, the pyrolysis of representative molecules of this substance class will be investigated in shock-tube experiments. On the one hand, shock tube experiments coupled with gas chromatography (GC/MS) and time-of-flight mass-spectrometry (TOF-MS), and on the other hand, flow reactor experiments coupled with GC/MS will be carried out to determine the composition of reaction products obtained during pyrolysis. As a result, the required kinetics information of the initial unimolecular reactions can be determined and important secondary reactions can be identified. With the help of experimental results and the Reaction Mechanism Generator (RMG) code developed by MIT, reaction models are being developed and optimized. An important contribution to this is provided by the rate rule expressions for the description of H-abstraction reactions.In this project, the complementary expertise of the Institute for Combustion and Gas Dynamics (IVG) of the University of Duisburg-Essen and the Institute of Combustion Technology (DLR Stuttgart) will be brought together. The experimental work on H abstraction by OH radicals, the time-resolved measurements by mass spectrometry, the flow reactor measurements, and the ab initio TST calculations are assigned to the IVG, while the experiments on H abstraction by H atoms in isotope-labeled components, the measurement of product compositions by shock-tube-experiments with GC/MS and the development of reaction mechanisms are assigned to the DLR Stuttgart.