Valecillos José, Ruiz-Martinez Javier, Aguayo Andrés T, Castaño Pedro
Department of Chemical Engineering, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain.
KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), P.O. Box 4700, Thuwal, 23955-6900, Saudi Arabia.
Chemistry. 2021 Apr 16;27(22):6719-6731. doi: 10.1002/chem.202004865. Epub 2021 Jan 28.
The dynamics of the retained species on ZSM-5 and SAPO-18 catalysts are studied by using a combination of temperature-programmed desorption/oxidation, ex situ analysis, and in situ FTIR spectroscopic measurements over the entire conversion range, using fixed-bed and spectroscopic cell reactors, in continuous and discontinuous mode. The results point to the appropriateness of the combined methodologies to track the interconversion of active into deactivating species. A statistically relevant (supported by linear regression and multivariate analysis) association of the observations is found by using the different complementary methodologies. The kinetics of this interconversion depends on the initial conversion (tuned by acidity and space time) and microporous topology, and involve: (i) in the ZSM-5 catalysts, the diffusion of monocyclic aromatics toward the exterior of the zeolite to form coke, and (ii) in the SAPO-18 catalysts, the obstruction of the cavities by aromatics that grow into tetracyclic aromatic islands.
通过在整个转化范围内，结合程序升温脱附/氧化、非原位分析和原位傅里叶变换红外光谱测量，使用固定床和光谱池反应器，以连续和不连续模式，研究了ZSM-5和SAPO-18催化剂上保留物种的动力学。结果表明，组合方法适用于追踪活性物种向失活物种的相互转化。通过使用不同的互补方法，发现观测结果具有统计学相关性（由线性回归和多变量分析支持）。这种相互转化的动力学取决于初始转化率（由酸度和时空调节）和微孔拓扑结构，并且涉及：(i) 在ZSM-5催化剂中，单环芳烃向沸石外部扩散以形成焦炭；(ii) 在SAPO-18催化剂中，芳烃生长成四环芳烃岛导致孔道堵塞。
