Heterogeneity of acid sites in ZSM-5 zeolites and boralites studied by IRspectroscopy and a catalytic method

Abstract

The conversion of cyclohexanol on acid sites in zeolites and boralites is composed of twosteps: dehydration (to cyclohexene and water) and consecutive reactions of cyclohexene: skeletal isomerization and disproportionation. Our IR and catalytic studies have shown that the dehydration occurs on both strong and weak Brönsted sites. On the other hand, only the strong Brönsted acid sites are required for isomerization and disproportionation. This observation may be used to propose a new method for investigation of heterogeneity of acid sites in zeolites by a simple catalytic test.