Toluene alkylation with methanol could serve as a green “molecular engineering” to produce para‐xylene (PX). However, the conversion and para‐selectivity are the key index to the application of this technology. Based on the reaction network and kinetics, the fixed‐bed models were introduced to analyze and optimize the para‐selectivity at reactor level. After the validation with the experimental results, the analysis of reaction kinetics showed that increasing temperature not only improves the main reaction rate, toluene conversion, and para‐selectivity, but also inhibits the competitiveness of methanol autocatalytic reaction, while higher feed molar ratio of toluene to methanol will suppress the olefins formation but reduce the conversion and promote the polymethylation process with a sharper temperature rise. Then, the one‐ and three‐dimensional model demonstrated that the conditions of 500‐520°C, feed molar ratio of 2‐3 would be favorable to the para‐selectivity, and keeping the wall 20‐30°C above the inlet temperature is beneficial for conversion, selectivity, and temperature control. These results have certain guiding value for the choice of reactor condition and further reactor design.

中文翻译：

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固定床反应器中甲醇催化甲苯烷基化的模拟

用甲醇进行甲苯烷基化可以作为绿色的“分子工程”来生产对二甲苯（PX）。但是，转化率和对位选择性是该技术应用的关键指标。根据反应网络和动力学，引入固定床模型以分析和优化反应器级的对位选择性。通过实验结果验证后，对反应动力学的分析表明，升高温度不仅提高了主反应速率，甲苯转化率和对位选择性，而且还抑制了甲醇自催化反应的竞争力，同时提高了甲苯的进料摩尔比甲醇制得的甲醇将抑制烯烃的形成，但会降低转化率并在温度急剧升高的情况下促进聚甲基化过程。然后，一维和三维模型表明，在500-520°C的条件下，进料摩尔比为2-3会有利于对位选择性，将壁温度保持在高于入口温度20-30°C时是有利的用于转化，选择性和温度控制。这些结果对于选择反应器条件和进一步的反应器设计具有一定的指导价值。