Fig. 1: Mechanism of DME carbonylation in mordenite.

a Pore and channel sizes of mordenite, kinetic sizes of methanol, dimethyl ether, and methyl acetate. The 8MR window refers to the opening between the 12MR channel and the 8MR side pocket (SP) of mordenite. b Catalytic cycle of DME carbonylation, the red arrows indicate the rate-determining step, and the green arrows indicate the fast step. c Free energy profile over MOR-8MR, MOR-12MR, and MOR-SP at 473 K obtained using the PBE-D3/dgdzvp method. d Energy decomposition analysis between organic species and zeolite framework at TS3 in MOR-8MR and MOR-12MR. Host-guest interactions of TS3 in the zeolite framework visualized using the reduced density gradient: e MOR-8MR, including both 8MR and SP; and f MOR-12MR. Red: repulsion, green: attraction.