Acetylene Separation by a Ca-MOF Containing Accessible Sites of Open Metal Centers and Organic Groups.

Efficient separation of acetylene from a ternary acetylene-containing mixture is an important and vital task in petrochemical industry, which is difficult to achieve using a single material. Herein, a new Ca-based metal-organic framework (MOF) [Ca(dtztp)(DMA)]·2HO () was constructed using the ,-donor ligand 2,5-di(2-tetrazol-5-yl)terephthalic acid and the less-studied alkaline earth Ca ions. The MOF shows a 3D honeycomb framework based on unique metal-carboxylate-azolate rod secondary building units. Owing to the presence of high-density organic hydrogen-bonding acceptors and open metal sites (OMSs), the activated MOF shows high adsorption capacity for CH and selectivity for CH over CO, CH, CH, and CH. Dynamic breakthrough experiments indicated the actual CH separation potential of the MOF from binary (CH-CH and CH-CO) and ternary (CH-CH-CO and CH-CH-CH) mixtures. Simulations revealed that the synergistic interactions between the OMSs and N atoms in MOF and CH molecules play an important role in the separation of CH.