In this article, a binderless dealuminated HZSM‐5 zeolite (Si/Al = 41.4) was used as a catalyst for the isomerization of a mixture of ethylbenzene and xylene. The experimental results indicated that at low residence times the catalyst is effective to isomerize the ethylbenzene into xylenes. A comprehensive kinetic model considering chemisorption, surface chemical reactions, and diffusional processes was developed for this reaction. The intrinsic activation energy (71.99 kJ mol⁻¹) for the surface reaction of ethylbenzene into m‐xylene was calculated for the first time, and the corresponding intrinsic activation energies for o‐xylene to m‐xylene and m‐xylene to p‐xylene surface reactions were calculated to be 59.45 and 50.68 kJ mol⁻¹, respectively. Lower apparent values have been reported in the literature, and we rationalize that they correspond to multistep processes and intrinsically include a negative activation energy pertaining to chemisorption. The results also revealed that the ethylbenzene diffusion within the zeolite channels was four orders of magnitude smaller than p‐xylene.

中文翻译：

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再谈HZSM-5沸石上乙苯/二甲苯异构化反应的动力学模型

在本文中，将无粘结剂的脱铝HZSM-5沸石（Si / Al = 41.4）用作乙苯和二甲苯混合物异构化的催化剂。实验结果表明，在低停留时间下，该催化剂可有效地将乙苯异构化为二甲苯。一个综合的动力学模型考虑了化学吸附，表面化学反应和扩散过程。本征活化能（71.99千焦耳摩尔^-1乙苯的表面反应成）米二甲苯计算为第一次，和所述对应的固有活化能ø二甲苯以米二甲苯和米二甲苯到p二甲苯表面反应经计算分别为59.45和50.68 kJ mol ^-1。较低的表观值已在文献中报道，我们将其合理化为它们对应于多步过程，并固有地包含与化学吸附有关的负活化能。结果还表明，乙苯在沸石通道内的扩散比对二甲苯小四个数量级。