Sulfated zirconia Subject

Moreover, the accessibility of sites causes discrepancies in the different methods and to measure the acidity of solids. Because several reviews on this subject have been published in recent years,27-29 we will just illustrate this problem with sulfated zirconia (SZ), probably the most studied single catalyst in the last 20 years. 

The conclusion that cubic zirconia yields active catalysts after sulfation finds further proof in the comparison of the properties of ZrOz samples without any alkaline earth metal dope. Table 2 shows that sample lZS-0 prepared by precipitation under neutral conditions and having some cubic phase has much higher activity than purely monoclinic sample 2ZS-0. However, the anion stabilization of the cubic phase does not seem to present any practical interest since catalyst lZS-0 is subjected to a relatively fast deactivation. Its activity after the first isomerization-regeneration cycle is several times lower than its initial... 

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