Grand canonical Monte Carlo and molecular dynamics simulations were used to investigate the adsorption and diffusion of benzene in ITQ-1 zeolite. The adsorption energies and preferred adsorption sites of benzene in ITQ-1 were first determined by using grand canonical Monte Carlo simulations. The obtained mass clouds showed that the diffusion of benzene occurred mainly in 12-member ring super-cages where the preferred adsorption sites of benzene could be divided into three separate adsorption sites. Molecular dynamics simulations were then used to analyze dynamic diffusion processes in zeolite. From the trajectories followed by the benzene molecules, it could be seen that the guest molecules did not diffuse in both channel systems, and only intracage mobility was seen in the super-cage voids. The two benzene molecules near to the S2 and S3 sites preferred to adopt a synergistic state; indicating that the benzene molecules at the S2 and S3 sites could produce relatively strong aromatic stacking interactions. Two sets of potential parameters were compared. For the molecules studied, these two force fields furnished similar and comparable results, although the interaction energy and adsorption isotherms exhibited some differences.

Adsorption and Diffusion of Benzene in ITQ-1 Type Zeolite: Grand Canonical Monte Carlo and Molecular Dynamics Simulation Study. Hou, T.J., Zhu, L.L., Xu, X.J.: Journal of Physical Chemistry B, 2000, 104[39], 9356-64