Theoretical Study for Adsorption-Diffusion on H-MOR and Pyridine Pre-adsorbed H-MOR of Dimethyl Ether Carbonylation.

For dimethyl ether (DME) carbonylation, pyridine pre-adsorbed hydrogen mordenite (H-MOR) is beneficial to prolonging the catalyst life. The adsorption and diffusion behaviors on periodic models H-AlMOR and H-AlMOR-Py were simulated. The simulation was based on Monte Carlo and molecular dynamics. The following conclusions were drawn from the simulation results. The adsorption stability of CO in 8-MR is increased, and the adsorption density of CO in 8-MR is more concentrated on H-AlMOR-Py. 8-MR is the main active site for DME carbonylation, so the introduction of pyridine would be beneficial for the main reaction. The adsorption distributions of methyl acetate (MA) (in 12-MR) and H 2 O on H-AlMOR-Py are significantly decreased. It means the product MA and the byproduct H 2 O are more easily desorbed on H-AlMOR-Py. For the mixed feed of DME carbonylation, the feed ratio ( P CO / P DME ) must reach 50:1 on H-AlMOR so that the reaction molar ratio can reach the theoretical value ( N CO / N DME ≈ 1:1), while the feed ratio on H-AlMOR-Py is only up to 10:1. Thus, the feed ratio can be adjusted, and raw materials can reduce consumption. In conclusion, H-AlMOR-Py can improve the adsorption equilibrium of reactants CO and DME and increase the concentration of CO in 8-MR.