Insight into Carbocation‐Induced Noncovalent Interactions in the Methanol‐to‐Olefins Reaction over ZSM‐5 Zeolite by Solid‐State NMR Spectroscopy
Chao Wang, Yueying Chu, Min Hu, Wenjin Cai, Qiang Wang, Guodong Qi, Shenhui Li, Jun Xu, Feng Deng
Abstract
Abstract Carbocations such as cyclic carbenium ions are important intermediates in the zeolite‐catalyzed methanol‐to‐olefins (MTO) reaction. The MTO reaction propagates through a complex hydrocarbon pool process. Understanding the carbocation‐involved hydrocarbon pool reaction on a molecular level still remains challenging. Here we show that electron‐deficient cyclopentenyl cations stabilized in ZSM‐5 zeolite are able to capture the alkanes, methanol, and olefins produced during MTO reaction via noncovalent interactions. Intermolecular spatial proximities/interactions are identified by using two‐dimensional 13 C– 13 C correlation solid‐state NMR spectroscopy. Combined NMR experiments and theoretical analysis suggests that in addition to the dispersion and CH/π interactions, the multiple functional groups in the cyclopentenyl cations produce strong attractive force via cation‐induced dipole, cation–dipole and cation–π interactions. These carbocation‐induced noncovalent interactions modulate the product selectivity of hydrocarbon pool reaction.