erent carbenium ion intermediates in zeolites with identical chabazite topology via 13 C – 13 C through-bond NMR correlations †

The production of light olens via the methanol-to-olens (MTO) reaction is an important chemical process that links non-oil resources such as coal and natural gas with olen-based petrochemicals. The catalysts used for the MTO reaction are mainly microporous acidic zeolites amongst which H-SAPO-34, a silicoaluminophosphate zeolite with the chabazite (CHA) topology, is of particular importance due to its high selectivity to ethylene and propene, and is of commercial use. H-SSZ-13 is a CHA silicoaluminate analogue of H-SAPO-34 which has been shown to be a potential alternative in the MTO process. Despite the successful industrialization of this process with methanol conversion higher than 99%, further improving of the catalyst performances in terms of selectivity has been an important scientic endeavor. For example, the selectivity to ethylene and propene has increased from 79.2% in the rst generation industrial DMTO process (“D” refers to Dalian Institute of Chemical Physics) to 85.7% in the second generation DMTO-II process in China. However, there is still signicant room to improve catalysts performances which can be informed by providing a deeper understanding of the catalytic reaction intermediates and reaction mechanism. We and others have previously investigated the MTO mechanism onH-ZSM-5,H-SAPO-34 11–14 b zeolite using a range of experimental and computational approaches including solidstate Nuclear Magnetic Resonance (NMR). The hydrocarbon pool (HCP) mechanism has been generally accepted for the