Morphology-Dependent Catalytic Performance of Mordenite in Carbonylation of Dimethyl Ether: Enhanced Activity with High c/b Ratio

The morphology of zeolite often plays an important role in catalytic performance. Controllable synthesis of zeolite with special morphology and elucidating the structure–performance relationship of microporous zeolite are significant to its application. In this work, rod-assembled H-MOR with a controllable c/b ratio was successfully fabricated via template-free hydrothermal methods. NH3 adsorption IR and pyridine-adsorbed IR were employed to quantify the amount of acid sites in 8-MR and 12-MR of MOR. By excluding the influence of acidic properties on activity, the rate of methyl acetate formation via dimethyl ether carbonylation has been proved proportionally dependent on c/b ratio. Pressure–composition–temperature measurements revealed that the reactant, CO, readily enriches in the longer channels in the c-axis direction, resulting in an enhanced methyl acetate formation. Meanwhile, a higher concentration of CO in channels as well as severer diffusion limitation in the H-MOR with a higher c/b ratio results in a faster deactivation rate.