Molecular simulation of adsorption of alkanes in sodium MOR-type zeolites using a new force field.
The applicability of a recently proposed force field of Calero et al. (J. Am. Chem. Soc., 2004, 126, 11377) to Na-MOR zeolites is evaluated. The Henry law coefficients of ethane and C(5)-C(9) as well as the adsorption isotherms of ethane, propane, butane, and hexane in various Na-MOR zeolites are computed and compared with experimental values. These comparisons show that the new force field is suitable for Na-MOR zeolites. Furthermore, this force field is used to study the effects of sodium cations on the adsorption behavior of larger alkanes, such as C(4)-C(7), in MOR-type zeolites. These simulations give a better understanding of the underlying mechanisms of the cations' position and density influence on adsorption. In addition, a characteristic pressure named "reversal pressure" is introduced which characterizes the efficiency of the presence of cations in zeolites.
Liu
Bei
B
Centre Européen de Calcul Atomique et Moléculaire (CECAM), Ecole Normale Supérieure, 46 allée d'Italie, 69007 Lyon, France. bliu@science.uva.nl
Smit
Berend
B
D000327:Adsorption; D000473:Alkanes / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D003198:Computer Simulation; D008956:Models, Chemical; D011312:Pressure; D011789:Quantum Theory; D012964:Sodium / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry*
D000473:Alkanes; D000538:Aluminum Silicates; C048397:mordenite; D017641:Zeolites; D012964:Sodium