Fan Shu-Cong, Li Yun-Tong, Wang Ying, Wang Jia-Wen, Xue Ying-Ying, Li Hai-Peng, Li Shu-Ni, Zhai Quan-Guo
Key Laboratory of Macromolecular Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, China.
Inorg Chem. 2021 Dec 6;60(23):18473-18482. doi: 10.1021/acs.inorgchem.1c03044. Epub 2021 Nov 19.
Acetylene (CH) purification is of great importance for many chemical synthesis and processes. Metal-organic frameworks (MOFs) are widely used for gas adsorption and separation due to their variable structure and porosity. However, the exploitation of ideal MOF adsorbents for CH keeps a challenging task. Herein, a combination of open metal sites (OMSs) and Lewis basic sites (LBSs) in robust MOFs is demonstrated to effectively promote the CH purification performance. Accordingly, SNNU-37(Fe/Sc), two isostructural MOFs constituted by [FeO(COO)] or [ScO(COO)] trinuclear clusters and amide-functionalized tricarboxylate linkers, were designed with extra-stable 3,6-connected new architectures. Derived from the coexistence of high-density OMSs and LBSs, the CH adsorption amounts of SNNU-37(Fe/Sc) are much higher than those values for CH and CO. Theoretical IAST selectivity values of SNNU-37(Fe) are 2.4 for CH/CH (50/50, v/v) and 9.9 for CH/CO (50/50, v/v) at 298 K and 1 bar, indicating an excellent CH separation ability. Experimental breakthrough curves also revealed that SNNU-37(Fe) could effectively separate CH/CH and CH/CO under ambient conditions. GCMC simulations further indicate that open Fe or Sc sites and amide groups mainly contribute to stronger adsorption sites for CH molecules.
乙炔（CH）的提纯对于许多化学合成和工艺来说至关重要。金属有机框架材料（MOFs）因其结构多变和孔隙率高而被广泛用于气体吸附和分离。然而，开发用于CH的理想MOF吸附剂仍然是一项具有挑战性的任务。在此，我们证明了在坚固的MOFs中开放金属位点（OMSs）和路易斯碱性位点（LBSs）的组合能有效提升CH的提纯性能。因此，SNNU - 37(Fe/Sc)，这两种由[FeO(COO)]或[ScO(COO)]三核簇和酰胺官能化三羧酸连接体构成的同构MOFs，被设计成具有超稳定的3,6连接新结构。源于高密度OMSs和LBSs的共存情况，SNNU - 37(Fe/Sc)对CH的吸附量远高于对CH和CO的值。在298 K和1 bar条件下，SNNU - 37(Fe)对CH/CH（50/50，v/v）的理论IAST选择性值为2.4，对CH/CO（50/50，v/v）为9.9，表明其具有出色的CH分离能力。实验突破曲线还表明，SNNU - 37(Fe)在环境条件下能有效分离CH/CH和CH/CO。GCMC模拟进一步表明，开放的Fe或Sc位点以及酰胺基团主要为CH分子提供了更强的吸附位点。
