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

Abstract

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 <i>c</i>/<i>b</i> 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 <i>c</i>/<i>b</i> ratio. Pressure-composition-temperature measurements revealed that the reactant, CO, readily enriches in the longer channels in the <i>c</i>-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 <i>c</i>/<i>b</i> ratio results in a faster deactivation rate.