Catalytic cycles for hydrocarbon cracking on zeolites

Catalytic cracking of hydrocarbons takes place via elementary reactions such as initiation processes to form carbenium ions, olefin adsorption/desorption steps, isomerization, beta-scission, oligomerization, and hydride ion transfer steps. These elementary steps involving reactive carbenium ion surface intermediates are the essential components of catalytic cracking that lead to various catalytic cycles and their corresponding stoichiometric reactions. This review outlines methods used to quantify reaction kinetics for catalytic cracking and describes how the rates of specific catalytic cycles are controlled by catalyst treatment (e.g., steaming) and process conditions (e.g., conversion and temperature).