Ideal Cage-like Pores for Molecular Sieving of Butane Isomers with High Purity and Record Productivity.

n-C 4 H 10 and iso-C 4 H 10 are both important petrochemical raw materials. Considering the coexistence of the isomers in the production process, it is necessary to achieve their efficient separation through an economical way. However, to obtain high-purity n-C 4 H 10 and iso-C 4 H 10 in one-step separation process, developing iso-C 4 H 10 -exclusion adsorbents with high n-C 4 H 10 adsorption capacity is crucial. Herein, we report a cage-like MOF (SIFSIX-Cu-TPA) with small windows and large cavities which can selectively allow smaller n-C 4 H 10 enter the pore and accommodate a large amount of n-C 4 H 10 simultaneously. Adsorption isotherms reveal that SIFSIX-Cu-TPA not only completely excludes iso-C 4 H 10 in a wide temperature range, but also exhibits a very high n-C 4 H 10 adsorption capacity of 94.2 cm 3  g -1 at 100 kPa and 298 K, which is the highest value among iso-C 4 H 10 -exclusion-type adsorbents. Breakthrough experiments show that SIFSIX-Cu-TPA has excellent n/iso-C 4 H 10 separation performance and can achieve a record-high productivity of iso-C 4 H 10 (3.2 mol kg -1 ) with high purity (>99.95 %) as well as 3.0 mol kg -1 of n-C 4 H 10 (>99 %) in one separation circle. More importantly, SIFSIX-Cu-TPA can realize the efficient separation of butanes at different flow rates, temperatures, as well as under high humid condition, which indicates that SIFSIX-Cu-TPA can be deemed as an ideal platform for industrial butane isomers separation.