A strategy to mitigate diffusion restrictions associated with heavy crude oil conversions is using mesostructured Y zeolite. In recent years, multiple routes have been proposed for obtaining materials with improved catalytic performance versus catalysts with higher molecular transport restrictions. Typically, after the implementation of these treatments, improvement in catalytic activity is correlated either with changes in textural properties (area and porous volume) or the modification of physicochemical properties (Si/Al ratio and acid strength); however, the correlation with diffusional mass transport characteristics is not typical. In this study, alkylaromatic molecules of different kinetic diameters, such as benzene, toluene, p–xylene, and m–xylene, were used as molecule probes to determine the effective diffusion through a pulse experiment under conditions of no adsorption or reaction. The studied solids include five commercial zeolites from the Zeolyst CBV series and four top–down mesostructured Y zeolites. The obtained concentration curves were fitted to an exponential decay model, a solution of the second Fick's law under defined experimental conditions, and correlation values between 0.9996 > R > 0.9896 were found. Furthermore, the implementation of the descriptors “Transport ratio (TR)” and “Corrected transport ratio (TR)” was proposed, which allowed the combined representation of the change in the mass transport of aromatic probes and the changes in the acidity of the zeolite, after the application of top–down treatments. These descriptors proved simple and effective tools to correlate the changes after mesopore insertion with the catalytic performance in the 1,3,5–Triisopropylbenzene (TIPB) cracking reaction. Our approach is an integral method of screening mesostructured zeolites with an adequate balance of acidity and transport properties.

中文翻译：

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烷基芳族传质——商业和介观结构 Y 沸石的酸度特性与裂化反应催化行为的相关性

减轻与重质原油转化相关的扩散限制的策略是使用介观结构 Y 沸石。近年来，人们提出了多种途径来获得相对于具有更高分子传输限制的催化剂具有改进催化性能的材料。通常，实施这些处理后，催化活性的提高与结构特性（面积和多孔体积）的变化或物理化学特性（Si/Al比和酸强度）的改变相关；然而，与扩散传质特性的相关性并不典型。本研究以苯、甲苯、对二甲苯、间二甲苯等不同动力学直径的烷基芳烃分子为分子探针，通过脉冲实验在无吸附或无反应的条件下测定有效扩散。研究的固体包括 Zeolyst CBV 系列的五种商用沸石和四种自上而下的介观结构 Y 沸石。将获得的浓度曲线拟合到指数衰减模型，即在定义的实验条件下菲克第二定律的解，并发现0.9996 > R > 0.9896之间的相关值。此外，还提出了描述符“传输比（TR）”和“校正传输比（TR）”的实现，这允许组合表示芳香族探针的质量传输的变化和沸石酸度的变化，在应用自上而下的处理之后。这些描述符被证明是简单而有效的工具，可以将介孔插入后的变化与 1,3,5-三异丙苯 (TIPB) 裂解反应的催化性能相关联。我们的方法是筛选具有适当平衡的酸度和传输特性的介观结构沸石的整体方法。