Metal confined in metal‐organic framework‐based mixed matrix membranes for efficient butadiene recognition separation

Abstract The efficient separation of butadiene (1,3‐C 4 H 6 ) from C 4 hydrocarbons is a critical step in petrochemical processes. However, the traditional cryogenic distillation suffers from energy‐intensity and serious environmental stress, necessitating the development of alternative technologies for efficient 1,3‐C 4 H 6 separation. Herein, a 1,3‐C 4 H 6 recognition mixed matrix membrane is reported via incorporating metal copper encapsulated a metal‐organic framework (CuBTC@Cu) into elastic poly(dimethylsiloxane) (PDMS). The resulting CuBTC@Cu/PDMS membrane can efficient separate 1,3‐C 4 H 6 from various C 4 hydrocarbons including 1,3‐C 4 H 6 /n‐C 4 H 8 , 1,3‐C 4 H 6 /iso‐C 4 H 8 , 1,3‐C 4 H 6 /n‐C 4 H 10 and 1,3‐C 4 H 6 /iso‐C 4 H 10 , yielding superior selectivity of 5.11, 6.35, 4.78, and 10.30, respectively, with 1,3‐C 4 H 6 permeability of 53240 Barrer. Notably, the appropriate π‐complexation interaction between butadiene molecules and CuBTC@Cu as well as suitable transmission channel size enable the membrane only permeable to 1,3‐C 4 H 6 and block the permeation of other C 4 hydrocarbons, showing a unique 1,3‐C 4 H 6 recognition behavior in membrane separation. The concept of affinity‐relying separation combining molecular sieving would open a new direction for designing gas membranes for efficient light hydrocarbon separations.