The relevance of a selection of organic impurities for the initiation of the MTO process was quantified in a kinetic model comprising 107 elementary steps with ab initio computed reaction barriers (MP2:DFT). This model includes a representative part of the autocatalytic olefin cycle as well as a direct initiation mechanism starting from methanol through CO-mediated direct C–C bond formation. We find that the effect of different impurities on the olefin evolution varies with the type of impurity and their partial pressures. The reactivity of the considered impurities for initiating the olefin cycle increases in the order formaldehyde < di-methoxy methane < CO < methyl acetate < ethanol < ethene < propene. In our kinetic model, already extremely low quantities of impurities such as ethanol lead to faster initiation than through direct C–C bond formation which only matters in complete absence of impurities.

中文翻译：

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杂质对甲醇制烯烃过程引发的影响：基于 Ab Initio 速率常数的动力学建模

选择有机杂质与 MTO 过程启动的相关性在动力学模型中进行量化，该模型包括 107 个基本步骤，并从头计算反应势垒 (MP2:DFT)。该模型包括自催化烯烃循环的代表性部分以及从甲醇开始通过 CO 介导的直接 C-C 键形成的直接引发机制。我们发现不同杂质对烯烃析出的影响随杂质类型及其分压的不同而不同。引发烯烃循环的所考虑杂质的反应性按甲醛 < 二甲氧基甲烷 < CO < 乙酸甲酯 < 乙醇 < 乙烯 < 丙烯的顺序增加。在我们的动力学模型中，