Notably, Corma and coworkers developed a flexible pure silica zeolite (ITQ-55) that achieved a kinetic selectivity of ~ 100 for C2H4/C2H6 separation . This selectivity was attributed to the unique pore topology and flexibility of its 8-membered ring (8MR) windows, which provided a precise fit for C2H4, enhancing its diffusion. However, the use of a complex and costly organic structure-directing agent (OSDA) in the synthesis of ITQ-55 limits its feasibility for industrialscale applications.