Efficient adsorptive separation of propene over propane through a pillar-layer cobalt-based metal-organic framework

The purification of propene from the propene/propane binary mixture is one of the most important and challenging separation processes in the chemical industry. In this study, a cobalt-based pillar-layer metal-organic framework, Co(AIP)(BPY)(0.5), was synthesized. It exhibited excellent water and moisture stability and efficient C3H6/C3H8 separation performance. At 298 K and 100 kPa, the adsorption capacity of C3H6 was 1.99 mmol/g and the IAST adsorption selectivity was 21, which has exceeded most investigated MOFs adsorbents. The cyclic breakthrough experiments of C3H6/C3H8 binary mixture confirmed its efficient dynamic separation property and excellent recyclability. The molecular simulation showed that the C3H8 molecules with multiple binding sites (CH) were restricted at the middle of the one-dimensional channel. Compared with C3H6, the large steric hindrance of C3H8 caused lower diffusion rate (with a C3H6/C3H8 kinetic selectivity of 29.7, at 303 K) in the narrow pore system of 1, which has been confirmed by the kinetic adsorption experiments.