A metal-carboxylate chains metal-organic framework decorated with N/O binding sites for MTO productions separation

As key building blocks in the chemical industry, ethylene (C 2 H 4 ) and propylene (C 3 H 6 ) are the primary target products of the methanol-to-olefins (MTO) process, which offers a promising alternative to traditional petroleum-based routes for olefin production. The separation of C 2 H 4 and C 3 H 6 constitutes a critical step in this process. Herein, we present a metal-carboxylate chains MOF ( NUM-21 ), possessing suitable pore aperture and the presence of nitrogen/oxygen (N/O) binding sites distributed within the pore channels, which enables the effective capture of C 3 H 6 and direct C 2 H 4 purification from binary C 3 H 6 /C 2 H 4 mixtures. The NUM-21a (activated NUM-21 ) exhibits a significantly higher C 3 H 6 adsorption capacity (54.6 cm 3 g −1 ) compared to C 2 H 4 (42.1 cm 3 g −1 ) at 298 K and 1 bar. Dynamic breakthrough experiments further demonstrated the effective separation of C 3 H 6 /C 2 H 4 mixtures with varying compositions over NUM-21a . Grand Canonical Monte Carlo (GCMC) simulations revealed that C 3 H 6 molecules exhibit stronger interactions with the framework than C 2 H 4 . Moreover, NUM-21 displays excellent recyclability and cycling stability under ambient pressure conditions. This work highlights the significance of rational MOF design for gas separation and offers valuable insights for the efficient separation of MTO products.