In recent years, the adsorptive air separation was established as one of the most important thermal separation processes for the generation of nitrogen and oxygen from air. Both the effects of equilibrium and kinetics can be applied for the separation of nitrogen and oxygen. Nitrogen can be enriched by an equilibrium effect in the adsorbed phase of zeolites, whereas oxygen remains in the gas phase. In contrast to zeolites, oxygen can diffuse much faster into the pores of carbon molecular sieves resulting in a gas phase enriched with nitrogen. In order to exploit this kinetic separation effect in industrial applications, the properties of carbon molecular sieves, e.g., pore aperture, overall pore volume, or release of heat of adsorption are important. Furthermore, research activities are focused on theoretical approaches to describe the kinetic behavior.