A robust indium-organic framework with open tubular channels for efficient separation of acetylene

Considering the tremendous applications and purification requirement of acetylene (C2H2), seeking appropriate adsorbents with high capacity and selectivity is a vital task and remains an enduring challenge. Herein, we designed and synthesized a robust three-dimensional (3D) indium-organic framework ([(Me)2NH2][In(L6)0.5(IPA)0.5] dimethylammonium (DMA)2H2O (In-L6-IPA)) featuring two types of one-dimensional (1D) tubular channels. The activated In-L6-IPA displayed high loading for C2H2 (104.4 cm3·g−1, the second highest value among all reported indium-based metal-organic frameworks (MOFs)) and simultaneously selective adsorption for C2H2 over CO2, C2H6, and ethylene (C2H4) at 298 K under 100 kPa. Molecular modelling revealed that the porous wall of In-L6-IPA provides more and stronger multiple interactions for C2H2 than CO2, C2H6, and C2H4 containing C–H⋯π, C–H⋯O, and O⋯π interactions. Breakthrough experiments validated the actual separation ability for various ratios of binary C2H2/C2H4 and C2H2/CO2 mixtures as well as equimolar ternary C2H2/C2H4/CO2 and C2H2/C2H4/C2H6 mixtures with excellent reusability.