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Download fileMethanol to Olefins Reaction Route Based on Methylcyclopentadienes as Critical Intermediates
journal contribution
posted on 2019-07-18, 15:34 authored by Wenna Zhang, Yuchun Zhi, Jindou Huang, Xinqiang Wu, Shu Zeng, Shutao Xu, Anmin Zheng, Yingxu Wei, Zhongmin LiuStarting
from C1 raw material, methanol conversion to hydrocarbons
has been realized via a rather complicated pathway. In this contribution,
we proposed an alternative methanol reaction route and provided a
general understanding of such complex indirect mechanism. The methylcyclopentenyl
cations and their deprotonated counterparts (methylcyclopentadienes)
were validated to appear on the working H-SAPO-34 catalyst by in situ 13C MAS NMR spectroscopy and the GC-MS technique, and their
catalytic reactivity was revealed by the 12C/13C–CH3OH isotopic switch experiment. In this context,
a cyclopentadienes-based cycle was established, in which light olefins
were formed with methylcyclopentadienes as critical intermediates.
The feasibility of this alternative route was confirmed by density
functional theory calculations. Notably, the cyclopentadienes-based
cycle runs in parallel with the traditional alkenes-based and aromatics-based
cycles; these three mechanistic cycles are interrelated through interconversion
of the involved intermediates, including alkene, cyclopentadiene,
and aromatic species. All these three cycles work together for the
C–C bond assembly in the methanol-to-olefins reaction system.
These findings help to build a more complete methanol conversion network
and advance the in-depth understanding of indirect mechanism of methanol
conversion.