Iron catalyst, amorphous surface area

Silica gel cracking catalysts have also been studied. These materials are amorphous and yield no powder diagrams but they do give a very maiked small angle scatter. If the particle distributions obtained from small angle scatter are used to calculate surface areas and these areas are related to the activity, fairly reasonable correlations result. Certain complications concerning these relationships are introduced by various types of treatments applied to the catalysts and by the iron content of commercially deactivated samples. 

When Ae bentonite clays are treated with acids, up to 80% of the aluminum can be extracted from the montmorillonite lattice together with most of the magnesium and iron. No silica is dissolved during the extraction process, but it is probable that some may be peptized to form an active amorphous phase with alumina. This increases the surface area and pore volume of the catalyst. Typical analyses of commercial catalysts shown in Table 5.4 indicate that sulfuric acid was a common activating agent. ... 

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