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 multifunct ional probe for testing the outer surface activity of zeolites. Its us e is demonstrated by the hydrogenation of the double bond over platinu m/H-BEA, in which comparison with various non zeolite-based platinum c atalysts enabled the proportion of platinum clusters located on the ou ter surface to be quantified. The Bronsted acid-catalysed Claisen rear rangement of the probe molecule, followed by the cyclization of the pr imary product to 4,6-di-tert-butyl-2-methyldihydrobenzofuran illustrat es the use of the probe to provide information regarding the outer sur face acidity of H-MOR and H-BEA. This test reaction proved also to be useful for the investigation of the effects of various modifications o f H-MOR on the outer surface acidity.