Highly efficient production of aromatics from C2H5Cl coupling with CO over H-zeolites

Abstract

Value-added utilization of C₂H₆ as an important component of natural gas and petrochemical by-products has attracted much attention. Aromatic synthesis from C₂H₆ is a crucial direction but remains a significant challenge due to its high stability. Chloroethane (C₂H₅Cl) is an essential derivative of C₂H₆, which effectively solves the C–H bond activation of C₂H₆. Herein, we report a pathway for the synthesis of aromatics via the coupling of CO and C₂H₅Cl over H-ZSM-5. Up to 76% aromatics selectivity is achieved via the coupling strategy whereas it is only 40% with the traditional methods. The introduction of CO not only facilitates the conversion of C₂H₅Cl, but also enhances the selectivity to aromatics over H-ZSM-5. Cyclopentenone species are detected and proved to be the key intermediate leading to a markedly improved aromatics selectivity. The ¹³C isotope tracing experiment reveals that CO participates in the formation of cyclopentenone species and aromatics. Furthermore, C₂H₄ formed from C₂H₅Cl has been observed to undergo carbonylation processes over H-ZSM-5. This work further expands the coupling reaction system between small molecule compounds and CO, providing an insight for natural gas conversion on H-zeolites.