Acetic Acid Leaching on the Structure, Acidity and Performance of HMOR Catalyst

Acid sites located inside the 8-ring side-pockets of mordenite are highly active for DME carbonylation.However, mordenite deactivates very fast during the reaction because of non-selective reactions happening inside the12-ring main channels of zeolites. In the present study, HMOR was treated by acid leaching using acetic acid of different concentration, with the purpose to selectively remove framework Al which is located inside 12-ring channels.Physicochemical characteristics of the parent and acid-treated mordenites were studied by complementary methods including: XRD, 27 Al-NMR, NH3-TPD, pyridine IR, and N2 adsorption-desorption. The results show that the acid treatment, if appropriately applied, increases both the Si/Al and micropore volume of the samples, without significantly changing the mesopore size distribution. Most of the framework Al species in the 12-membered ring channels of HMOR were removed, without impacting those located inside the 8-ring channels. The catalytic results show that the initial