The concentration dependence of ethene diffusion in the lattice of H[Al]ZSM-5 was studied for loadings of 1, 2, 4, 6 or 8 molecules per unit cell at 300K. Data on interactions, heat of adsorption and self-diffusion coefficients were obtained. It was found that the molecular self-diffusion coefficient decreased, with loading, from 12.62 x 10-9m2/s at 1mol/unit-cell to 2.96 x 10-9m2/s at 8mol/unit-cell. The interaction between ethene molecules increased with increasing molecular occupancy.

Concentration Dependence of Ethene Diffusion in H[Al]ZSM-5 Studied by Molecular Dynamics. Jianfen, F., Qiuxia, W., Xuedong, G., Heming, X.: Journal of Molecular Structure, 2003, 638, 129-34