Highly Enhanced Aromatics Selectivity by Coupling of Chloromethane and Carbon Monoxide over H‐ZSM‐5

Abstract

AbstractThe transformation of methane into high value‐added chemicals such as aromatics provides a more desired approach towards sustainable chemistry but remains a critical challenge due to the low selectivity of aromatics and poor stability. Herein, we first report a coupling reaction of CH3Cl and CO (CCTA) based on methane conversion, which achieves extremely high aromatics selectivity (82.2 %) with the selectivity of BTX up to ca. 60 % over HZSM‐5. The promoting effects have been demonstrated on other zeolites especially 10‐membered rings (10 MR) zeolites. Multiple characterizations show that 2,3‐dimethyl‐2‐cyclopentene‐1‐one (DMCPO) is generated from acetyl groups and olefins. Furthermore, isotopic labeling analysis confirms that CO is inserted into the DMCPO and aromatics rings. A new aromatization mechanism is proposed, including the formation of the above intermediates, which conspicuously weakens the hydrogen transfer reaction, leading to a considerable increase of aromatics selectivity and a dramatic drop in alkanes.