Enhancement of the dimethyl ether carbonylation activation via regulating acid sites distribution in FER zeolite framework

The carbonylation of dimethyl ether (DME) with CO is a key step for ethanol synthesis from syngas, but traditional mordenite (MOR) zeolite shows low catalytic stability. Herein, various FER zeolite nanosheets were prepared with four types of organic templates. The catalytic performance of FER in DME carbonylation is strongly dependent on the location of strong acid site in framework, which can be effectively regulated by altering organic template. FER-MORP sample synthesized with morpholine shows the highest DME conversion of 53%, thus, giving a methyl acetate space-time yield (STYMA) of 0.889 mmol g-1 h-1. DFT calculation, NH3-IR, 1H/27Al/29Si MAS NMR, and in situ DRIFTS results indicate that morpholine directs more Al species, or strong Bronsted acid sites (BAS), to locate in 8-membered ring (8-MR) channels, which not only enhances carbonylation activity but also suppresses formation of coke species. The catalytic performance is well maintained within 4 repeated recycles (similar to 460 h).

Automated summary

Various FER zeolite nanosheets were prepared with different organic templates, and FER-MORP sample synthesized with morpholine showed the highest DME conversion and methyl acetate space-time yield. The study also revealed that morpholine can enhance the carbonylation activity and suppress the formation of coke species.