A theoretical study on the feed ratio of dimethyl ether carbonylation on H-MOR zeolites

Monte Carlo and molecular dynamics simulations were performed for the adsorption-diffusion properties of dimethyl ether (DME) and carbon monoxide (CO) pure gas and mixture with different feed ratio in H-MOR zeolite to find out the influence of feed ratio on the DME carbonylation activity. For pure gas, DME adsorbs stronger than CO with a competitive adsorption, and all molecules have relatively good diffusion properties. For the mixture, in low feed ratio (PCO/PDME = 1–10), the adsorption capacity of CO in 8-MR cannot meet the reaction requirement caused the low carbonylation activity, while increasing the feed ratio (to PCO/PDME = 20–30) will promote CO adsorption. The optimal feed ratio PCO/PDME ≈ 27:1 is also discovered. Furthermore, it can also reduce the total molecular per cell and improve the diffusion in each channel which is another factor for the carbonylation activity improvement.Highlights: The adsorption ratio of NCO/NDME in H-MOR was investigated from both adsorption and diffusion sides, which is the key factor affecting the activity of DME carbonylation.A new scheme was proposed to optimise the carbonylation activity by changing the feed ratio, and the mechanism of increase and decrease of feed ratio was analysed from a microscopic point of view.The optimal feed ratio PCO/PDME ≈ 27:1 for DME carbonylation in H-MOR was discovered.A wide range of experimental feed ratio data (covers PCO/PDME = 1:1 to PCO/PDME = 1:50), so this research work provides a new idea for the next subsequent modification of H-MOR, which is to reduce the optimal feed ratio to an acceptable level.