A new united atom force field for adsorption of alkenes in zeolites

A new united atom force field was developed that accurately describes the adsorption properties of linear alkenes in zeolites. The force field was specifically designed for use in the inhomogeneous system and therefore a truncated and shifted potential was used. With the determined force field, we performed a comparative study on the adsorption behaviors of ethene and propene in four pure-silica small-pore eight-membered-ring zeolites, CHA, DDR, ITE, and IHW (named Chabazite, DD3R, ITQ-3, and ITQ-32, respectively), characterized for their paraffin/olefin separation capability. The different macroscopic adsorption behaviors of alkenes in the four zeolites were elucidated and related to their structures with the microscopic information obtained from the molecular simulations providing useful information for further rational design of such zeolites with tailored properties.