Microscopic Analysis of Phase Transition Effects during Benzene Sorption in MFI Type Zeolites
نویسندگان
چکیده
Fig. 1: Silicalite-1 crystal, top: building scheme with 90° rotated subunits, bottom: picture of the x-z-plane in normal optical mode (transmission). 1. Introduction Adsorption of aromatic hydrocarbons in MFI zeolites has been intensively studied due to the importance of ZSM-5 and the aluminium-deficient analogue, Silicalite-1, in catalysis and separation. Applying different macroscopic techniques, e.g. gravimetric sorption isotherms, X-ray diffraction or solid-state NMR, several groups reported not only a phase transition of sorbate molecules under confinement of the zeolite lattice, but also minor changes of the framework structure itself depending on temperature and loading. Microscopic studies of individual crystals by means of interference microscopy (IFM) and IR microscopy (IRM) now reveal deeper insights into the sorption behaviour and phase changes of the aromatic-MFI system.
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