Fabricating a Robust Ultramicroporous Metal-Organic Framework for Purifying Natural Gas and Coal Mine Methane.

Purifying methane (CH) from natural gas and coal mine methane (CMM) is of great significance but challenging in the chemical industry. Herein, a robust ultramicroporous metal-organic framework (MOF) is reported, which can be synthesized on a gram scale by stirring under room temperature. Single-component adsorption isotherms of gases (CH, ethane (CH), propane (CH), nitrogen (N)) and breakthrough experiments indicate that the MOF can separate CH efficiently from CH/CH/CH ternary mixture, with super high purity-CH production of 154.7 cm g. Additionally, the MOF shows higher CH capacity than N, resulting in excellent separation performance for the CH/N mixture. Notably, the binding sites of gases can be precisely determined by single-crystal X-ray data, further confirmed by molecular simulation. It is found that there are multiple hydrogen bonds and C─H···π interactions between the gases and the framework. This work offers an excellent candidate material for CH purification with both high capacity and separation efficiency.