Effects of mordenite zeolite catalyst synthesis conditions on dimethyl ether carbonylation

Effects of different mordenite (MOR) zeolite synthesis conditions, such as salt additive, hydrothermal time, hydrothermal temperature, and ultrasonic assistance, on dimethyl ether (DME) carbonylation were studied systematically in this work. Salt as additives being introduced into hydrothermal system obviously promoted the crystallinity and morphology of MOR. With the increase of hydrothermal time and temperature, a better crystallinity was obtained on the sample. However, a higher hydrothermal temperature of 180 degrees C led to a slightly decreased crystallinity. The MOR catalyst with NaCl as the additive and hydrothermal treatment at 130 degrees C for 48 h realized a better DME carbonylation activity with 50% DME conversion and almost 100% methyl acetate (MA) selectivity. In addition, H-MOR-UT, a MOR zeolite prepared with the assistance of ultrasonic treatment, showed a special morphology consisting of lots of MOR nanosheets with a width of around 70 nm. Here, this H-MOR-UT realized an enhanced catalytic stability and the highest DME conversion of 70%, about 5 times higher than the reference MOR zeolite prepared by traditional method. The strikingly excellent catalytic performance was attributed to its more acid content, stronger acid strength and smaller grain size.