| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 75898 | Microporous and Mesoporous Materials | 2009 | 5 Pages |
The diffusional behavior of selected hydrocarbons adsorbed in NaX zeolites were investigated with pulsed magnetic field gradient (PFG) NMR methods in two different ways. First, the exchange time τexchτexch of n -pentane between the interior and the exterior of the zeolite crystals was determined by two-dimensional diffusion exchange spectroscopy. The results were compared to the mean life time τintraτintra as obtained by fast NMR tracer desorption method. Second, the diffusion of a propylene–propane mixture adsorbed in the zeolite was studied by Fourier transform PFG NMR, thus employing the chemical shift of the individual organic constituents as a second dimension for a selective evaluation of the PFG NMR signal decays and the subsequent extraction of corresponding diffusion coefficients. Modifications of NMR pulse sequences necessary for the application of ultra-high pulsed magnetic field gradients of up to ±35Tm-1 in microporous materials are briefly discussed for both kind of experiments.
