Wide Temperature Sieving of n‐Butene and iso‐Butene by a Zinc‐Based Coordination Network with Record Separation

Abstract Separating n‐butene and iso‐butene through adsorption represents a viable and energy‐efficient strategy. However, developing porous adsorbents that can effectively discern the subtle differences between these isomers remains a significant challenge. This study demonstrates that a zinc‐based coordination network (CALF‐20) exhibits a slight pore expansion with increasing temperature, creating nanochannels that preferentially adsorb n‐butene over iso‐butene. This unique temperature‐dependent dynamic behavior enables effective sieving of n‐butene from iso‐butene within the temperature range of 273 to 423 K, a phenomenon not previously observed. Notably, CALF‐20 exhibits the highest n‐butene adsorption capacity (2.62 mmol g⁻¹) and the highest selectivity ratio (14.7) among sieving materials reported to date for n‐butene isomers. Modeling calculations show that dynamic factors play a significant role in achieving such high adsorption separation capabilities. At medium temperatures, the initial separation of n‐butene and iso‐butene is achievable, which may provide a foundation for the future design of adsorbents intended to achieve efficient separation of n‐butene/iso‐butene under comparable temperature conditions. In the future, the intricate structure dynamics and enhanced capacity for molecular recognition will offer a new pathway for developing advanced sieving materials.