The adsorption of C7-C14 n-alkanes in the cages of ZIF-8 metal-organic framework is studied using hybrid Monte Carlo simulations to gain insights into the unusual odd-even behavior in diffusion recently observed in experiments. The results are analyzed in a variety of ways including data science to identify key packing differences among n-alkanes.
Recent experiments show that the diffusivities of C8 and C10 n-alkanes in ZIF-8 are higher than those of C7 and C9, respectively. We investigated this unusual ‘odd-even' effect by simulating the adsorption of C7-C14 n-alkanes in ZIF-8 using hybrid Monte Carlo molecular simulations. The resultant adsorption isotherms, guest-host energies, isosteric heats, and chain length distributions are analyzed for trends among the n-alkanes. ZIF-8 cages filled with n-alkanes are characterized using a combination of image processing and data science to quantify the differences in packing that occur with chain length. Results indicate that packing changes drastically from C7 to C8 and from C9 to C10, which is consistent with the diffusion trends previously reported in experiments.Zum Volltext