Insights into the CO-mediated deactivation mechanism for dimethyl ether carbonylation reaction over a H-MOR catalyst

Abstract

Dimethyl ether (DME) carbonylation to methyl acetate (MAc) catalyzed by H-MOR catalyst has aroused wide interest due to its high efficiency as an emerging method for ethanol production. However, the rapid deactivation of H-MOR catalyst results in great challenges for its industrial application, urging a clear understanding of the intricate carbonylation deactivation mechanism. Herein, we discover a CO-mediated deactivation mechanism over H-MOR catalyst, which is beyond the traditional understanding that deactivation is originated from DME/methanol-to-hydrocarbon (DTH/MTH) chemistry. It is revealed that the coupling reaction of CO or MAc with olefins accelerate the catalyst deactivation, and methyl cyclopentenones (MCPOs) are first identified as the key intermediates for aromatic cokes formation over H-MOR catalyst. A more comprehensive mechanism for DME carbonylation deactivation is proposed based on the understanding. This study would provide valuable insights into understanding the carbonylation process and offer potential directions for developing carbonylation catalysts with enhanced stability.