Ferri Pau, Li Chengeng, Millán Reisel, Martínez-Triguero Joaquín, Moliner Manuel, Boronat Mercedes, Corma Avelino
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Cientificas (UPV-CSIC), Av. de los Naranjos, s/n, 46022, Valencia, Spain.
Angew Chem Int Ed Engl. 2020 Oct 26;59(44):19708-19715. doi: 10.1002/anie.202007609. Epub 2020 Aug 18.
The methanol-to-olefins reaction catalyzed by small-pore cage-based acid zeolites and zeotypes produces a mixture of short chain olefins, whose selectivity to ethene, propene and butene varies with the cavity architecture and with the framework composition. The product distribution of aluminosilicates and silicoaluminophosphates with the CHA and AEI structures (H-SSZ-13, H-SAPO-34, H-SSZ-39 and H-SAPO-18) has been experimentally determined, and the impact of acidity and framework flexibility on the stability of the key cationic intermediates involved in the mechanism and on the diffusion of the olefin products through the 8r windows of the catalysts has been evaluated by means of periodic DFT calculations and ab initio molecular dynamics simulations. The preferential stabilization by confinement of fully methylated hydrocarbon pool intermediates favoring the paring pathway is the main factor controlling the final olefin product distribution.
由小孔笼型酸性沸石和类沸石催化的甲醇制烯烃反应会生成短链烯烃混合物，其对乙烯、丙烯和丁烯的选择性会随孔穴结构和骨架组成而变化。已通过实验确定了具有CHA和AEI结构的铝硅酸盐和硅铝磷酸盐（H-SSZ-13、H-SAPO-34、H-SSZ-39和H-SAPO-18）的产物分布，并通过周期性密度泛函理论计算和从头算分子动力学模拟评估了酸度和骨架柔韧性对该机理中关键阳离子中间体稳定性以及烯烃产物通过催化剂8r窗口扩散的影响。有利于配对途径的完全甲基化烃池中间体通过限域作用实现的优先稳定化是控制最终烯烃产物分布的主要因素。
