Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

Abstract

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether (DME) carbonylation reaction. The influence of Si/Al ratio in the feedstock on the structure, porosity and acid sites were systematically investigated. The characterization results showed that with the increase of Si/Al ratio in the feedstock, part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased. The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio, and the amount of strong acid slightly increased. The Al atoms preferentially enter the strong acid sites in the 8 MR channel during the crystallization process. The high Si/Al ratio sample had more acid sites located in the 8 MR channel, leading to more active sites for carbonylation reaction and higher catalytic performance. Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the MOR catalyst.