Sorption and Packing of n-Alkane Molecules in ZSM-5⁺

Sorption isotherms have been measured by using a gravimetric balance (Cahn 2000). Detailed sorp-tion/desorption isotherms have been obtained for ethane, propane, n-butane, and n-hexane on H-ZSM-5 (Si/Al = 132). From these sorption studies a sorption model has been proposed to describe n-alkane molecular packing as a function of sorbate loading in the ZSM-5/silicalite-l channel network. The model has been extended to account for the diffusional behavior of those molecules in this channel network in terms of an activated jump process, and comparisons have been made between the results obtained and published data for NMR jump-length dependence upon sorbate loading.