New multifunctional probe for testing outer surface activity of zeolites: Application to surface-located platinum clusters and acid sites

Allyl 3,5-di-tert-butylphenyl ether is being developed as a multifunctional probe for testing the outer surface activity of zeolites. Its use is demonstrated by the hydrogenation of the double bond over platinum/H-BEA, in which comparison with various non zeolite-based platinum catalysts enabled the proportion of platinum clusters located on the outer surface to be quantified. The Bronsted acid-catalysed Claisen rearrangement of the probe molecule, followed by the cyclization of the primary product to 4,6-di-tert-butyl-2-methyldihydrobenzofuran illustrates the use of the probe to provide information regarding the outer surface acidity of H-MOR and H-BEA. This test reaction proved also to be useful for the investigation of the effects of various modifications of H-MOR on the outer surface acidity.