| Abstract
| - The diffusion of C7 alkanes in the microporous material ITQ-2 has been investigated by molecular dynamicstechniques and the results were compared with those obtained for MCM-22. In MCM-22, differences indiffusivity are observed between the isomers n-heptane and 2-methylhexane, especially in the sinusoidal 10member ring (MR) system. Similar features in the diffusivity are observed in the supercages, and no intercagediffusion has been observed at any of the temperatures of the simulation (ranging from 450 to 650 K), whichwould suggest that a much longer time scale is needed for intercage diffusion to be observed. Intracagediffusion is a temperature-activated process. In ITQ-2 the diffusion in the supercage system has been studiedusing 2-methylhexane as the probe molecule. Important differences appear with respect to MCM-22 becauseof the opening of the supercages giving chalice-type pores. The molecules have a tendency to penetrate intothe chalice, but the subsequent out-diffusion is not restrained by the 10 MR windows interconnecting thesupercages, as these windows, present in MCM-22, do not exist in ITQ-2. This allows the 2-methylhexaneto escape from the 12 MR system more easily than in MCM-22. Possible catalytic applications of ITQ-2 areanalyzed in view of the results.
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