The mechanism of shape selectivity is largely dependent on the [pore size and structure] of the catalyst. Reactant molecules with dimensions that fit within the pores can enter and undergo catalysis, while larger molecules are excluded. This can lead to three types of shape selectivity:
1. Reactant Selectivity: Only certain reactants can enter the pores to interact with the active sites. 2. Product Selectivity: The pores may favor the formation of certain products over others. 3. Transition-State Selectivity: The catalyst may stabilize certain transition states, thereby influencing the reaction pathway and product distribution.
