Effect of Zr Incorporation on Mordenite Catalyzed Dimethyl Ether Carbonylation

Abstract

Zr-mordenite catalysts were prepared by post-treatment method and H-mordenite catalyst was synthesized by hydrothermal method for the dimethyl ether carbonylation reaction. XRD, N2 adsorption/desorption, ICP-OES, SEM, TEM, UV–Vis, XPS, Raman, CO-TPD, NH3-TPD, 27Al MAS NMR, FTIR and Py-IR were employed to characterize the catalysts. The results demonstrated that part of Zr atoms existed in a tetrahedral coordination state after incorporating into the mordenite framework. Zirconium Lewis acid sites with the ability to absorb CO molecules were formed during this process although the amount of Bronsted acid sites in 8-member ring channels decreased upon the incorporation of zirconium. During the concentration of zirconium nitrate solution increased from 0.02 to 0.08 mol/L, the Zr-mordenite catalyst through post-treatment with 0.04 mol/L zirconium nitrate solution exhibited the best catalytic performance at 473 K and 1 MPa. Dimethyl ether conversion and methyl acetate selectivity increased to 78% and 96% respectively compared with H-mordenite catalyst. Schematic of Zr incorporating MOR framework