Interaction of Surface and Gas Reactions in High Temperature (max ca. 1300°C) High Pressure (max. ca. 5 M Pa) Catalytic Alkane Oxidations

将甲烷和乙烷等天然气成分转化为甲醇、甲醛或乙烯等有价值的化学品，是21世纪催化研究和化学工程的一大挑战。高温高压下的非均相催化烷烃氧化可能是大规模完成这些转化的一种方法，前提是有可能控制催化剂表面和周围气相反应之间的相互作用，并最大限度地通过动力学控制部分氧化产物的形成。通过采用新的原位诊断技术，在高达1300°C的反应温度和高达5 M Pa的压力下研究表面和气体化学，该项目将有助于对催化烷烃氧化过程中化学和物理表面气体相互作用的机理理解，这在很大程度上是实验研究人员以前从未探索过的。为了比较不同催化材料上表面-气体耦合反应的性质和重要性，本文研究了金属催化剂（Pt）、强碱性偶联催化剂（Li/MgO）和氧化还原催化剂（vox）。气体种类，表面和气体温度剖面没有和有同位素标记将测量µm空间和ms时间分辨率使用新开发的毛细管技术与质谱或气相色谱物质分析。用分子束质谱法研究气相自由基。这两种技术都是为这个项目做准备而开发的。利用光纤探针空间分辨拉曼光谱对催化剂、气体种类、吸附种类和焦炭沉积物进行研究。共聚焦拉曼显微镜将用于绘制催化剂-气体边界层以探索质量和热输运。将进行数值模拟，以比较最先进的微动力学表面和气体模型与实验数据，并揭示决定速率参数的选择性。如果可能的话，将进行改进。通过现场实验和数值模拟相结合的知识将用于定制催化剂，反应器和反应条件，以获得部分氧化产物的最佳产量。基于知识的高温高压催化烷烃氧化动力学控制可以推动部分氧化产物的产量进入经济利益区域，并且可以提高天然气作为化学原料的使用，除了作为清洁燃料之外。

The transformation of natural gas components like methane and ethane into valuable chemicals like methanol, formaldehyde or ethylene is a big challenge for catalysis research and chemical engineering in the 21st century. Heterogeneous catalytic alkane oxidations at high temperatures and pressures might be a way to accomplish these transformations on a large scale provided that it is possible to control the interaction between reactions at the catalyst surface and in the surrounding gas phase and to maximize the kinetically controlled formation of partial oxidation products. By employing novel in-situ diagnostic techniques to investigate surface and gas chemistry under reaction temperatures up to 1300 °C and pressures up to 5 M Pa, this project will contribute to a mechanistic understanding of chemical and physical surface gas interactions in catalytic alkane oxidations under conditions, largely unexplored by experimental researchers before. To compare nature and importance of coupled surface - gas reactions on different catalytic materials, a metallic catalyst (Pt), a strong basic coupling catalyst (Li/MgO) and a redox catalyst (V Ox) will be investigated. Gas species, surface and gas temperature profiles without and with isotope labelling will be measured with µm spatial and ms time resolution using a newly developed capillary technique with MS or GC species analysis. Gas phase radicals will be studied by molecular beam mass spectrometry. Both techniques have been developed in preparation for this project. Spatially resolved Raman spectroscopy with a fiber probe will be applied to study the catalyst, gas species, adsorbed species and coke deposits. Confocal Raman microscopy will be used to map the catalyst-gas boundary layer to explore mass and heat transport. Numerical simulations will be performed to compare state-of-the-art microkinetic surface and gas models against the experimental data and to reveal selectivity determining rate parameters. If possible, improvements will be made. The knowledge derived by combining in-situ experiments and numerical simulations will be used to tailor catalyst, reactor and reaction conditions for optimum yields of partial oxidation products. A knowledge based control of the kinetics of high temperature high pressure catalytic alkane oxidations could push the yields of partial oxidation products into regions of economic interest and could enhance the use of natural gas as chemical feedstock in addition to its use as a clean fuel.