Adsorption in Reversed Order of C<sub>2</sub> Hydrocarbons on an Ultramicroporous Fluorinated Metal‐Organic Framework
Lingzhi Yang, Liting Yan, Weijing Niu, Yan Feng, Qiuju Fu, Shuo Zhang, Yinhang Zhang, Liangjun Li, Xin Gu, Pengcheng Dai, Dandan Liu, Qingbin Zheng, Xuebo Zhao
Abstract
Abstract Metal‐organic frameworks have been widely studied in the separation of C 2 hydrocarbons, which usually preferentially bind unsaturated hydrocarbons with the order of acetylene (C 2 H 2 )>ethylene (C 2 H 4 )>ethane (C 2 H 6 ). Herein, we report an ultramicroporous fluorinated metal‐organic framework Zn‐FBA (H 2 FBA=4,4′‐(hexafluoroisopropylidene)bis(benzoic acid)), shows a reversed adsorption order characteristic for C 2 hydrocarbons, that the uptake for C 2 hydrocarbons of the framework and the binding affinity between the guest molecule and the framework follows the order C 2 H 6 >C 2 H 4 >C 2 H 2 . Density‐functional theory calculations confirm that the completely reversed adsorption order behavior is attributed to the close van der Waals interactions and multiple cooperative C−H⋅⋅⋅F hydrogen bonds between the framework and C 2 H 6 . Moreover, Zn‐FBA exhibits a high selectivity of about 2.9 for C 2 H 6 over C 2 H 4 at 298 K and 1 bar. The experimental breakthrough studies show that the high‐purity C 2 H 4 can be obtained from C 2 H 6 and C 2 H 4 mixtures in one step.