The effects of steam aging temperature on the properties of an HY zeolite of the type used in FCC preparations

Lewis Acids: From Conventional Homogeneous to Green Homogeneous and Heterogeneous Catalysis

“…688 With respect to the Lewis acidity, this property is associated with the presence of extraframework Al species produced during the zeolite activationdealumination process and any other cation exchange. 689 The extraframework Al species behaving as Lewis acids play an important role in cracking bottoms, but also tend to produce more gases and coke. 690,691 It is remarkable that, while the effect of Lewis acidity (extraframework Al) is clear when cracking vacuum gasoil, there is a controversy about the role played by this type of acid sites when cracking pure hydrocarbons.…”

Influence of FCC catalyst steaming on HDPE pyrolysis product distribution

“…It is known that during steaming, important changes occur on the catalyst composition (dealumination) and structure (surface area). Moreover, both acid site density and the number of strong acid sites in the structure drastically decrease [36]. The effect of these changes over the product distribution obtained in the catalytic pyrolysis of HDPE has been studied.…”

Solid-State Nuclear Magnetic Resonance

“…An important contribution is the demonstration that, at sufficiently high field, 27 Al NMR detects all the aluminum in a zeolite material (20). Reactions of Y zeolite with fluorine or fluoride solutions cause degradation of the material that can be detected with NMR spectroscopy (21,22). Studies with NMR allowed one group to discern the position of the fluoride ion in a siliceous material including tetrapropylammonium fluoride (23).…”