Formselektive Katalyse in Zeolithen

Abstract

Shape selective catalysis in zeolites. In recent years, shape selective catalysis has become an important field of heterogeneous catalysis. Shape selectivity can arise if the pore width of the catalyst resembles the dimensions of molecules or transition states involved in the catalytic reaction. Up till now, zeolites are employed almost exclusively as shape selective catalysts. Examples of the different kinds of shape selectivity are given. The classification of Weisz and Csicsery is presented. More recent concepts are discussed. Measures for a control of shape selectivity are outlined. For a routine characterization of shape selective catalysts, certain test reactions are shown to be useful tools; the two most important examples are the determination of the constraint index and the hydroconversion of long chain n‐alkanes.