Introduction

Over thirty-five years ago, Weisz and Frilette coined the term shape selective catalysis to describe the then unexpected intrinsic catalytic activities of synthetic crystalline molecular sieve zeolites. They found that the calcium ion exchanged zeolite A, having “port” sizes of 4 to 5 A selectively cracked straight chain n-paraffins to exclusively straight chain products. Molecular shape selective zeolites have gone from being laboratory curiosities to becoming commercially significant groups of industrial catalysts. More recently shape selective catalysis has extended from the medium pore zeolites to several large pore zeolites, including ZSM-4, zeolite L and zeolite Beta. Over the years, the principles of shape selective catalysis have been comprehensively reviewed by a number of authors. This chapter aims to summarize the impact of shape selective catalysis on the petroleum and petrochemical industries.