Creating uniform pores for xenon/krypton and acetylene/ethylene separation on a strontium-based metal-organic framework

Industrial separations of xenon/krypton and acetylene/ethylene systems are challenging and energy-intensive processes. Exploring new porous material for their separation is of great significance. We reported here a strontium based thermostable metal-organic framework [Sr-4(TCPE4-)(2)(DMF)(4)(H2O)(4)](n)center dot solvent (1) (TCPE = tetrakis(4-carboxyphenypethylene) with quadrangular pores possess diameter of 3.60 angstrom (type-1 pore). Heating the MOF 1 in vacuum can drive the coordinated solvent molecules away and open the type-2 pores with diameter of 4.40 angstrom. This contributes to xenon and acetylene absorption with Xe/Kr selectivity of 6.93 (Xe/Kr = 20:80) and acetylene/ethylene selectivity of 1.75 (acetylene/ethylene = 1:99). The density functional theory (DFT) calculations revealed the interactions between the MOF skeleton and the absorbed Xe atom.