An investigation was made of the minimum-energy positions and short-term self-diffusion of butene isomers in the zeolite structures, TON, MTT, MEL, MFI, FER and HEU. The minimum-energy positions, and the corresponding interaction energies, essentially reflected the steric interaction between the guest molecule and the host zeolite walls. It was shown that, in all structures except TON, trans-2-butene diffused faster than did the other isomers. In all cases except TON and MTT, the diffusion of isobutene could not be followed during a 200ps molecular dynamics run. In zeolite TON, the ratio of isobutene versus linear butene self-diffusion was larger than in the other zeolites. This indicated that, in this structure, diffusion was probably not the rate-limiting process.

Energetics and Diffusion of Butene Isomers in Channel Zeolites from Molecular Dynamics Simulations. Jousse, F., Leherte, L., Vercauteren, D.P.: Journal of Molecular Catalysis A, 1997, 119[1-3], 165-76