An Ultramicroporous Metal–Organic Framework\nfor High Sieving Separation of Propylene from Propane

Abstract

Highly\nselective adsorptive separation of olefin/paraffin through\nporous materials can produce high purity olefins in a much more energy-efficient\nway than the traditional cryogenic distillation. Here we report an\nultramicroporous cobalt gallate metal–organic framework (Co-gallate)\nfor the highly selective sieving separation of propylene/propane at\nambient conditions. This material possesses optimal pore structure\nfor the exact confinement of propylene molecules while excluding the\nslightly large propane molecules, as clearly demonstrated in the neutron\ndiffraction crystal structure of Co-gallate⊃0.38C₃D₆. Its high separation performance has been confirmed\nby the gas sorption isotherms and column breakthrough experiments\nto produce the high purity of propylene (97.7%) with a high dynamic\nseparation productivity of 36.4 cm³ cm^–3 under ambient conditions. The gas adsorption measurement, pore size\ndistribution, and crystallographic and modeling studies comprehensively\nsupport the high sieving C₃H₆/C₃H₈ separation in this MOF material. It is stable under different\nenvironments, providing its potential for the industrial propylene\npurification.