Types of Catalysts
Commonly used isomerization catalysts include:

Platinum-based catalysts: Such as Pt/Al2O3 (platinum on alumina support), which are typically employed for the isomerization of normal paraffins.
Bifunctional catalysts: Containing both metallic and acidic sites, like platinum combined with zeolites (e.g., Pt/H-USY). The metallic component provides dehydrogenation activity, whereas the acidic sites promote the formation and migration of carbocation intermediates leading to molecular structure rearrangements.
Working Mechanism
Adsorption and Activation: Initially, hydrocarbon molecules are adsorbed onto the catalyst surface where they undergo preliminary activation by a metal center, usually platinum. This may involve partial dehydrogenation reactions to produce corresponding olefins or cyclic compounds.
Protonation and Carbocation Formation: Subsequently, activated hydrocarbons pick up a proton at acidic sites, forming carbocation intermediates. These cations are unstable and tend to undergo structural rearrangements to achieve more stable configurations.
Rearrangement and Isomerization: Through a series of hydrogen shifts, methyl migrations, or skeletal rearrangements, carbocation intermediates evolve into isomers with different branching structures. The key aspect here lies in the mobility and stability of these carbocations.